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1. The operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations

Author: C. W. Hergenrother, C. K. Maleszewski, M. C. Nolan, J.-Y. Li, C. Y. Drouet d’Aubigny, F. C. Shelly, E. S. Howell, T. R. Kareta, M. R. M. Izawa, M. A. Barucci, E. B. Bierhaus, H. Campins, S. R. Chesley, B. E. Clark, E. J. Christensen, D. N. DellaGiustina, S. Fornasier, D. R. Golish, C. M. Hartzell, B. Rizk, D. J. Scheeres, P. H. Smith, X.-D. Zou, D. S. Lauretta, and The OSIRIS-REx Team
Subjects: Science
Abstract: Vicinity of small bodies might be dangerous to the spacecrafts and to their instrumentation. Here the authors show the operational environment of asteroid Bennu, validate its photometric phase function and demonstrate the accelerating rotational rate due to YORP effect using the data acquired during the approach phase of OSIRIS-REx mission.
Published: 2019
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2. Hydrogen Abundance and Distribution on (101955) Bennu

Author: A. Praet, M. A. Barucci, B. E. Clark, H. H. Kaplan, A. A. Simon, V. E. Hamilton, J. P. Emery, E. S. Howell, L. F. Lim, X.-D. Zou, J.-Y. Li, D. C. Reuter, F. Merlin, J. D. P. Deshapriya, S. Fornasier, P. H. Hasselmann, G. Poggiali, S. Ferrone, J. R. Brucato, D. Takir, E. Cloutis, H. C. Connolly Jr, M. Fulchignoni, and D. S. Lauretta
Subjects: Astronomy
Abstract: Asteroids were likely a major source of volatiles and water to early Earth. Quantifying the hydration of asteroids is necessary to constrain models of the formation and evolution of the Solar System and the origin of Life on Earth. The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) mission showed that near-Earth asteroid (101955) Bennu contains widespread, abundant hydrated phyllosilicates, indicated by a ubiquitous absorption at ~ 2.7 μm. The objective of this work is to quantify the hydration—that is, the hydrogen content—of phyllosilicates on Bennu's surface and investigate how this hydration varies spatially. We analyse spectral parameters (normalized optical path length, NOPL; effective single-scattering albedo, ESPAT; and Gaussian modeling) computed from the hydrated phyllosilicate absorption band of spatially resolved visible–near-infrared spectra acquired by OVIRS (the OSIRIS-REx Visible and InfraRed Spectrometer). We also computed the same spectral parameters using laboratory-measured spectra of meteorites including CMs, CIs, and the ungrouped C2 Tagish Lake. We estimate the mean hydrogen content of water and hydroxyl groups in hydrated phyllosilicates on Bennu's surface to be 0.71 ± 0.16 wt%. This value is consistent with the hydration range of some aqueously altered meteorites (CMs, C2 Tagish Lake), but not the most aqueously altered group (CIs). The sample collection site of the OSIRIS-REx mission has slightly higher hydrogen content than average. Spatial variations in hydrogen content on Bennu's surface are linked to geomorphology, and may have been partially inherited from its parent body.
Published: 2021
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3. Weak Spectral Features on (101995) Bennu from the OSIRIS-REx Visible and InfraRed Spectrometer

Author: A A Simon, H H Kaplan, E Cloutis, V E Hamilton, C Lantz, D C Reuter, D Trang, S Fornasier, B E Clark, and D S Lauretta
Subjects: Astronomy
Abstract: Context. The NASA Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission has obtained thousands of spectra of asteroid (101955) Bennu with the OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS). Aims. We present a spectral search for minor absorption bands and determine compositional variations on the surface of Bennu. Methods. Reflectance spectra with low and high spatial resolutions were analyzed for evidence of weak absorption bands. Spectra were also divided by a global average spectrum to isolate unique spectral features, and variations in the strongest band depths were mapped on a surface shape model. The global visible to near-IR spectrum of Bennu shows evidence of several weak absorption bands with depths of a few percent. Results. Several observed bands are consistent with phyllosilicates, and their distribution correlates with the stronger 2.74-μm hydration band. A 0.55-μm band is consistent with iron and is deepest in the spectrally reddest areas on Bennu. The presence of hydrated phyllosilicates and iron oxides indicates substantial aqueous alteration in Bennu’s past. Conclusions. Bennu’s spectra are not identical to a limited set of carbonaceous chondrite spectra, possibly due to compositional properties and spatial scale differences; however, returned samples should contain a mixture of common chondrite materials.
Published: 2020
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4. Variations in color and reflectance on the surface of asteroid (101955) Bennu

Author: D. N. DellaGiustina, K. N. Burke, K. J. Walsh, P. H. Smith, D. R. Golish, E. B. Bierhaus, R.-L. Ballouz, T. L. Becker, H. Campins, E. Tatsumi, K. Yumoto, S. Sugita, J. D. Prasanna Deshapriya, E. A. Cloutis, B. E. Clark, A. R. Hendrix, A. Sen, M. M. Al Asad, M. G. Daly, D. M. Applin, C. Avdellidou, M. A. Barucci, K. J. Becker, C. A. Bennett, W. F. Bottke, J. I. Brodbeck, H. C. Connolly Jr, M. Delbo, J. de Leon, C.Y. Drouet d’Aubigny, K. L. Edmundson, S. Fornasier, V. E. Hamilton, P. H. Hasselmann, C. W. Hergenrother, E. S. Howell, E. R. Jawin, H. H. Kaplan, L. Le Corre, L. F. Lim, J.Y. Li, P. Michel, J. L. Molaro, M. C. Nolan, J. Nolau, M. Pajola, A. Parkinson, M. Popescu, N. A. Porter, B. Rizk, J. L. Rizos, A. J. Ryan, B. Rozitis, N. K. Shultz, A. A. Simon, D. Trang, R. B. Van Auken, C. W. V. Wolner, and D. S. Lauretta
Subjects: Astronomy, Lunar And Planetary Science And Exploration
Abstract: Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. Here we present multispectral images (0.44 to 0.89 micrometers) of near-Earth asteroid (101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their reflectance and texture. Space weathering of Bennu surface materials does not simply progress from red to blue (or vice versa). Instead, freshly exposed, redder surfaces initially brighten in the near-ultraviolet region (i.e., become bluer at shorter wavelengths), then brighten in the visible to near-infrared region, leading to Bennu’s moderately blue average color. Craters indicate that the time scale of these color changes is ~105 years. We attribute the reflectance and color variation to a combination of primordial heterogeneity and varying exposure ages.
Published: 2020
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5. Exogenic Basalt on Asteroid (101955) Bennu

Author: D N DellaGiustina, H H Kaplan, A A Simon, W F Bottke, C Avdellidou, M Delbo, R-L Ballouz, D R Golish, K J Walsh, M Popescu, H Campins, M A Barucci, G Poggiali, R T Daly, L Le Corre, V E Hamilton, N Porter, E R Jawin, T J McCoy, H C Connolly Jr, J L Rizos Garcia, E Tatsumi, J de Leon, J Licandro, S Fornasier, M G Daly, M M Al Asad, L Philpott, J Seabrook, O S Barnouin, B E Clark, M C Nolan, E S Howell, R P Binzel, B Rizk, D C Reuter, and D S Lauretta
Subjects: Lunar And Planetary Science And Exploration
Abstract: When rubble-pile asteroid 2008 TC3 impacted Earth on October 7, 2008, the recovered rock fragments indicated that such asteroids can contain exogenic material. However, spacecraft missions to date have only observed exogenous contamination on large, monolithic asteroids that are impervious to collisional disruption. Here we report the presence of meter-scale exogenic boulders on the surface of near-Earth asteroid (101955) Bennu - the 0.5-km, rubble-pile target of the OSIRIS-REx mission which has been spectroscopically linked to the CM carbonaceous chondrite meteorites. Hyperspectral data indicate that the exogenic boulders have the same distinctive pyroxene composition as the howardite-eucrite-diogenite (HED) meteorites that come from (4) Vesta, a 525-km diameter asteroid that has undergone differentiation and extensive igneous processing. Delivery scenarios include the infall of Vesta fragments directly onto Bennu or indirectly onto Bennu’s parent body, where the latter’s disruption created Bennu from a mixture of endogenous and exogenic debris. Our findings demonstrate that rubble-pile asteroids can preserve evidence of inter-asteroid mixing that took place at macroscopic scales well after planetesimal formation ended. Accordingly, the presence of HED-like material on the surface of Bennu provides previously unrecognized constraints on the collisional and dynamical evolution of the inner main belt.
Published: 2020
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6. Phobos and Deimos surface composition: search for spectroscopic analogues

Author: Giovanni Poggiali, M Matsuoka, M A Barucci, J R Brucato, P Beck, S Fornasier, A Doressoundiram, F Merlin, and A Alberini
Subjects: Space and Planetary Science, Astronomy and Astrophysics
Abstract: Phobos and Deimos, the two satellites of Mars, were largely studied in the past using ground-based telescope and spacecraft data, although most of the data were obtained by opportunity observations performed by Mars dedicated orbiters. Despite the data available so far, the main composition of the two moons is not yet fully understood. The possible presence of hydrated minerals along with mafic minerals olivine and pyroxene seems to be the most plausible interpretation, but more investigations are needed. MIRS spectrometer on-board the future JAXA MMX sample return mission will help to unveil the open question on the composition of Phobos and Deimos. In this work, we review past spectroscopic observations of the Martian moons, both from ground observatories and spacecraft data set, aiming at better understanding the constraints in interpreting the Mars satellites composition and at identifying the best spectroscopic analogues. We also present new laboratory measurements on mineral mixing and meteorites to match the satellites spectral behaviour. New measurements were acquired at INAF-Astrophysical Observatory of Arcetri and IPAG laboratories at room conditions exploring different geometries and the results obtained set new constraints for future laboratory measurements. Our preliminary results confirm that the surface of Phobos and Deimos can be associated with samples characterized by a higher presence of dark components (e.g. amorphous carbon) or minerals produced by space weathering (e.g. Fe0 and FeS-bearing materials). Presence of dark component could also be totally responsible for the reduced hydrated band observed on the moons without invoking dehydration or OH-implantation on anhydrous surface.
Published: 2022

7. Volatile exposures on the 67P/Churyumov-Gerasimenko nucleus

Author: S. Fornasier, H. V. Hoang, M. Fulle, E. Quirico, and M. Ciarniello
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the most extensive catalog of exposures of volatiles on the 67P/Churyumov-Gerasimenko nucleus generated from observations acquired with the OSIRIS cameras on board the Rosetta mission. We identified more than 600 volatile exposures on the comet. Bright spots are found isolated on the nucleus or grouped in clusters, usually at the bottom of cliffs, and most of them are small, typically a few square meters or smaller. Several of them are clearly correlated with the cometary activity. We note a number of peculiar exposures of volatiles with negative spectral slope values in the high-resolution post-perihelion images, which we interpret as the presence of large ice grains ($>$ 1000 $μ$m) or local frosts condensation. We observe a clear difference both in the spectral slope and in the area distributions of the bright spots pre- and post-perihelion, with these last having lower average spectral slope values and a smaller size, with a median surface of 0.7 m$^2$, even if the size difference is mainly due to the higher resolution achieved post-perihelion. The minimum duration of the bright spots shows three clusters: an area-independent cluster dominated by short-lifetime frosts; an area-independent cluster with lifetime of 0.5--2 days, probably associated with the seasonal fallout of dehydrated chunks; and an area-dependent cluster with lifetime longer than 2 days consistent with water-driven erosion of the nucleus. Even if numerous bright spots are detected, the total surface of exposed water ice is less than 0.1% of the total 67P nucleus surface, confirming that the 67P surface is dominated by refractory dark terrains, while exposed ice occupies only a tiny fraction. Moreover, the abundance of volatile exposures is six times less in the small lobe than in the big lobe, adding additional evidence to the hypothesis that comet 67P is composed of two distinct bodies., 24 pages, 19 Figures; paper accepted for publication in Astron. and Astrophysics on February 2023
Published: 2023
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8. The unexpected surface of asteroid (101955) Bennu

Author: D. S. Lauretta, D. N. DellaGiustina, C. A. Bennett, D. R. Golish, K. J. Becker, S. S. Balram-Knutson, O. S. Barnouin, T. L. Becker, W. F. Bottke, W. V. Boynton, H. Campins, H. C. Connolly Jr, C. Y. Drouet d’Aubigny, J. P. Dworkin, J. P. Emery, H. L. Enos, V. E. Hamilton, C. W. Hergenrother, E. S. Howell, M. R. M. Izawa, H. H. Kaplan, M. C. Nolan, B. Rizk, H. L. Roper, D. J. Scheeres, P. H. Smith, K. J. Walsh, C. W. V. Wolner, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, L. McGraw, R. Ghent, R. P. Binzel, M. M. Al Asad, C. L. Johnson, L. Philpott, H. C. M. Susorney, E. A. Cloutis, R. D. Hanna, F. Ciceri, A. R. Hildebrand, E.-M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J. R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani, M. K. Crombie, C. Lantz, J. de Leon, J. Licandro, J. L. Rizos Garcia, S. Clemett, K. Thomas-Keprta, S. Van wal, M. Yoshikawa, J. Bellerose, S. Bhaskaran, C. Boyles, S. R. Chesley, C. M. Elder, D. Farnocchia, A. Harbison, B. Kennedy, A. Knight, N. Martinez-Vlasoff, N. Mastrodemos, T. McElrath, W. Owen, R. Park, B. Rush, L. Swanson, Y. Takahashi, D. Velez, K. Yetter, C. Thayer, C. Adam, P. Antreasian, J. Bauman, C. Bryan, B. Carcich, M. Corvin, J. Geeraert, J. Hoffman, J. M. Leonard, E. Lessac-Chenen, A. Levine, J. McAdams, L. McCarthy, D. Nelson, B. Page, J. Pelgrift, E. Sahr, K. Stakkestad, D. Stanbridge, D. Wibben, B. Williams, K. Williams, P. Wolff, P. Hayne, D. Kubitschek, M. A. Barucci, J. D. P. Deshapriya, S. Fornasier, M. Fulchignoni, P. Hasselmann, F. Merlin, A. Praet, E. B. Bierhaus, O. Billett, A. Boggs, B. Buck, S. Carlson-Kelly, J.Cerna, K. Chaffin, E. Church, M. Coltrin, J. Daly, A. Deguzman, R. Dubisher, D. Eckart, D. Ellis, P. Falkenstern, A. Fisher, M. E. Fisher, P. Fleming, K. Fortney, S. Francis, S. Freund, S. Gonzales, P. Haas, A. Hasten, D. Hauf, A. Hilbert, D. Howell, F. Jaen, N. Jayakody, M. Jenkins, K. Johnson, M. Lefevre, H. Ma, C. Mario, K. Martin, C. May, M. McGee, B. Miller, C. Miller, G. Miller, A. Mirfakhrai, E. Muhle, C. Norman, R. Olds, C. Parish, M. Ryle, M. Schmitzer, P. Sherman, M. Skeen, M. Susak, B. Sutter, Q. Tran, C. Welch, R. Witherspoon, J. Wood, J. Zareski, M. Arvizu-Jakubicki, E. Asphaug, E. Audi, R.-L. Ballouz, R. Bandrowski, S. Bendall, H. Bloomenthal, D. Blum, J. Brodbeck, K. N. Burke, M. Chojnacki, A. Colpo, J. Contreras, J. Cutts, D. Dean, B. Diallo, D. Drinnon, K. Drozd, R. Enos, C. Fellows, T. Ferro, M. R. Fisher, G. Fitzgibbon, M. Fitzgibbon, J. Forelli, T. Forrester, I. Galinsky, R. Garcia, A. Gardner, N. Habib, D. Hamara, D. Hammond, K. Hanley, K. Harshman, K. Herzog, D. Hill, C. Hoekenga, S. Hooven, E. Huettner, A. Janakus, J. Jones, T. R. Kareta, J. Kidd, K. Kingsbury, L. Koelbel, J. Kreiner, D. Lambert, C. Lewin, B. Lovelace, M. Loveridge, M. Lujan, C. K. Maleszewski, R. Malhotra, K. Marchese, E. McDonough, N. Mogk, V. Morrison, E. Morton, R. Munoz, J. Nelson, J. Padilla, R. Pennington, A. Polit, N. Ramos, V. Reddy, M. Riehl, S. Salazar, S. R. Schwartz, S. Selznick, N. Shultz, S. Stewart, S. Sutton, T. Swindle, Y. H. Tang, M. Westermann, D. Worden, T. Zega, Z. Zeszut, A. Bjurstrom, L. Bloomquist, C. Dickinson, E. Keates, J. Liang, V. Nifo, A. Taylor, F. Teti, M. Caplinger, H. Bowles, S. Carter, S. Dickenshied, D. Doerres, T. Fisher, W. Hagee, J. Hill, M. Miner, D. Noss, N. Piacentine, M. Smith, A. Toland, P. Wren, M. Bernacki, D. Pino Munoz, S.-i. Watanabe, S. A. Sandford, A. Aqueche, B. Ashman, M. Barker, A. Bartels, K. Berry, B. Bos, R. Burns, A. Calloway, R. Carpenter, N. Castro, R. Cosentino, J. Donaldson, J. Elsila Cook, C. Emr, D. Everett, D. Fennell, K. Fleshman, D. Folta, D. Gallagher, J. Garvin, K. Getzandanner, D. Glavin, S. Hull, K. Hyde, H. Ido, A. Ingegneri, N. Jones, P. Kaotira, L. F. Lim, A. Liounis, C. Lorentson, D. Lorenz, J. Lyzhoft, E. M. Mazarico, R. Mink, W. Moore, M. Moreau, S. Mullen, J. Nagy, G. Neumann, J. Nuth, D. Poland, D. C. Reuter, L. Rhoads, S. Rieger, D. Rowlands, D. Sallitt, A. Scroggins, G. Shaw, A. A. Simon, J. Swenson, P. Vasudeva, M. Wasser, R. Zellar, J. Grossman, G. Johnston, M. Morris, J. Wendel, A. Burton, L. P. Keller, L. Mcnamara, S. Messenger, K. Messenger, A. Nguyen, K. Righter, E. Queen, K. Bellamy, K. Dill, S. Gardner, M. Giuntini, B. Key, J. Kissell, D. Patterson, D. Vaughan, B. Wright, R. W. Gaskell, L. Le Corre, J.-Y. Li, J. L. Molaro, E. E. Palmer, M. A. Siegler, P. Tricarico, J. R. Weirich, X.-D. Zou, T. Ireland, K. Tait, P. Bland, S. Anwar, N. Bojorquez-Murphy, P. R. Christensen, C. W. Haberle, G. Mehall, K. Rios, I. Franchi, B. Rozitis, C. B. Beddingfield, J. Marshall, D. N. Brack, A. S. French, J. W. McMahon, E. R. Jawin, T. J. McCoy, S. Russell, M. Killgore, J. L. Bandfield, B. C. Clark, M. Chodas, M. Lambert, R. A. Masterson, M. G. Daly, J. Freemantle, J. A. Seabrook, K. Craft, R. T. Daly, C. Ernst, R. C. Espiritu, M. Holdridge, M. Jones, A. H. Nair, L. Nguyen, J. Peachey, M. E. Perry, J. Plescia, J. H. Roberts, R. Steele, R. Turner, J. Backer, K. Edmundson, J. Mapel, M. Milazzo, S. Sides, C. Manzoni, B. May, M. Delbo, G. Libourel, P. Michel, A. Ryan, F. Thuillet, and B. Marty
Subjects: Astronomy, Exobiology
Abstract: NASA’S Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft recently arrived at the near-Earth asteroid (101955) Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth1. Bennu is a low-albedo B-type asteroid2 that has been linked to organic-rich hydrated carbonaceous chondrites3. Such meteorites are altered by ejection from their parent body and contaminated by atmospheric entry and terrestrial microbes. Therefore, the primary mission objective is to return a sample of Bennu to Earth that is pristine—that is, not affected by these processes4. The OSIRIS-REx spacecraft carries a sophisticated suite of instruments to characterize Bennu’s global properties, support the selection of a sampling site and document that site at a sub-centimetre scale5,6,7,8,9,10,11. Here we consider early OSIRIS-REx observations of Bennu to understand how the asteroid’s properties compare to pre-encounter expectations and to assess the prospects for sample return. The bulk composition of Bennu appears to be hydrated and volatile-rich, as expected. However, in contrast to pre-encounter modelling of Bennu’s thermal inertia12 and radar polarization ratios13—which indicated a generally smooth surface covered by centimetre-scale particles—resolved imaging reveals an unexpected surficial diversity. The albedo, texture, particle size and roughness are beyond the spacecraft design specifications. On the basis of our pre-encounter knowledge, we developed a sampling strategy to target 50-metre-diameter patches of loose regolith with grain sizes smaller than two centimetres4. We observe only a small number of apparently hazard-free regions, of the order of 5 to 20 metres in extent, the sampling of which poses a substantial challenge to mission success.
Published: 2019
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9. Overview of the search for signs of space weathering on the low-albedo asteroid (101955) Bennu

Author: B.E. Clark, A. Sen, X.-D. Zou, D.N. DellaGiustina, S. Sugita, N. Sakatani, M. Thompson, D. Trang, E. Tatsumi, M.A. Barucci, M. Barker, H. Campins, T. Morota, C. Lantz, A.R. Hendrix, F. Vilas, L. Keller, V.E. Hamilton, K. Kitazato, S. Sasaki, M. Matsuoka, T. Nakamura, A. Praet, S.M. Ferrone, T. Hiroi, H.H. Kaplan, W.F. Bottke, J.-Y. Li, L. Le Corre, J.L. Molaro, R.-L. Ballouz, C.W. Hergenrother, B. Rizk, K.N. Burke, C.A. Bennett, D.R. Golish, E.S. Howell, K. Becker, A.J. Ryan, J.P. Emery, S. Fornasier, A.A. Simon, D.C. Reuter, L.F. Lim, G. Poggiali, P. Michel, M. Delbo, O.S. Barnouin, E.R. Jawin, M. Pajola, L. Riu, T. Okada, J.D.P. Deshapriya, J.R. Brucato, R.P. Binzel, and D.S. Lauretta
Subjects: Space and Planetary Science, Astronomy and Astrophysics
Published: 2023

10. Search for carbon-bearing compounds on low-albedo asteroids

Author: T Hromakina, M A Barucci, I Belskaya, S Fornasier, F Merlin, A Praet, G Poggiali, and M Matsuoka
Subjects: Space and Planetary Science, Astronomy and Astrophysics
Abstract: In this work we aim to investigate the presence of absorption bands around 3.4 μm in the infrared spectra of primitive asteroids. We collected the published reflectance spectra of low-albedo asteroids from the literature and analyzed the 2.4-3.8 μm region using the same techniques. From the initial dataset of 92 asteroids, we restricted our analysis to 42 spectra of low-albedo asteroids with a good signal-to-noise (S/N) ratio and we found the absorption feature around 3.4 μm in the spectra of 16 objects. For objects that are classified by the 3 μm band into the ’rounded’, Ceres-like, and Europa-like groups, the depth of the 3.4 μm feature is strongly correlated with that of the 3 μm band. The majority of objects in our dataset not showing the 3.4 μm absorption band have lower S/N spectra and belong to Ch or Chg classes, while asteroids with a detected 3.4 μm bands mostly belong to C, B, and also P types. Additionally, asteroids with a detected 3.4 μm band tend to have a lower albedo, redder J-K colors, and more neutral U-V colors. We observe that the analyzed objects larger than ∼300 km in diameter show features due to carbon-bearing materials, which could be explained by their higher S/N ratio in our dataset. Finally, we found that the distributions of asteroids showing the 3.4 μm feature appear to be shifted towards larger distances from the Sun compared to those not showing this band.
Published: 2022

11. Spectrophotometric characterization of the Philae landing site and surroundings with the Rosetta/OSIRIS cameras

Author: S. Fornasier, Carsten Güttler, Holger Sierks, Pedro Hasselmann, Eric Quirico, Hong Van Hoang, Cecilia Tubiana, Maria Antonietta Barucci, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Institut Universitaire de France (IUF), and Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, biology, Comet, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Albedo, biology.organism_classification, 01 natural sciences, Regolith, Methods observational, Phase angle (astronomy), 13. Climate action, Space and Planetary Science, 0103 physical sciences, Spectral slope, Water ice, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: We investigate Abydos, the final landing site of the Philae lander after its eventful landing from the Rosetta spacecraft on comet 67P/Churyumov–Gerasimenko on 2014 November 12. Over 1000 OSIRIS-level 3B images were analysed, which cover the 2014 August–2016 September timeframe, with spatial resolution ranging from 7.6 m pixel−1 to approximately 0.06 m pixel−1. We found that the Abydos site is as dark as the global 67P nucleus and spectrally red, with an average albedo of 6.5 per cent at 649 nm and a spectral slope value of about 17 per cent/(100 nm) at 50° phase angle. Similar to the whole nucleus, the Abydos site also shows phase reddening but with lower coefficients than other regions of the comet, which may imply a thinner cover of microscopically rough regolith compared to other areas. Seasonal variations, as already noticed for the whole nucleus, were also observed. We identified some potential morphological changes near the landing site implying a total mass-loss of (4.7–7.0) × 105 kg. Small spots ranging from 0.1 to 27 m2 were observed close to Abydos before and after perihelion. Their estimated water ice abundance reaches 30–40 per cent locally, indicating fresh exposures of volatiles. Their lifetime ranges from a few hours up to three months for two pre-perihelion spots. The Abydos surroundings showed a low level of cometary activity compared to other regions of the nucleus. Only a few jets are reported originating nearby Abydos, including a bright outburst that lasted for about 1 h.
Published: 2020

12. Photometric survey of 55 near-earth asteroids

Author: F. Colas, M. Fulchignoni, Mirel Birlan, E. Dotto, E. Petrescu, D. Perna, A. Sonka, S. Fornasier, T. Hromakina, M. A. Barucci, F. Merlin, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Agroécologie [Dijon], Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Observatorul Astronomic 'Amiral Vasile Urseanu' [Bucharest], Astronomical Observatory 'Admiral Vasile Urseanu', Bucharest Municipal Museum, the NEOROCKS Team, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Near-Earth object, 010504 meteorology & atmospheric sciences, Astronomy, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, asteroids: general, [SHS.HISPHILSO]Humanities and Social Sciences/History, Philosophy and Sociology of Sciences, techniques: photometric, surveys, Space and Planetary Science, 0103 physical sciences, minor planets, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Context. Near-earth objects (NEOs), thanks to their proximity, provide a unique opportunity to investigate asteroids with diameters down to dozens of meters. The study of NEOs is also important because of their potential hazard to the Earth. The investigation of small NEOs is challenging from Earth as they are observable only for a short time following their discovery and can sometimes only be reached again years or decades later. Aims. We aim to derive the visible colors of NEOs and perform an initial taxonomic classification with a main focus on smaller objects and recent discoveries. Methods. Photometric observations were performed using the 1.2 m telescope at the Haute-Provence observatory and the 1.0 m telescope at the Pic du Midi observatory in broadband Johnson-Cousins and Sloan photometric systems. Results. We present new photometric observations for 55 NEOs. Our taxonomic classification shows that almost half (43%) of the objects in our sample are classified as S+Q-complex members, 19% as X-complex, 16% as C-complex, 12% as D-types, and finally 6% and 4% as A- and V-types, respectively. The distribution of the observed objects with H > 19 and H ≤ 19 remains almost the same. However, the majority of the objects in our dataset with D < 500 m belong to the “silicate” group, which is probably a result of an observational bias towards brighter and more accessible objects. “Carbonaceous” objects are predominant among those with a Jovian Tisserand parameter of Tj < 3. These bodies could be dormant or extinct comets. The median values of the absolute magnitude for “carbonaceous” and “silicate” groups are H = 18.10 ± 0.95 and H = 19.50 ± 1.20, whereas the estimated median diameters are D = 1219 ± 729 m and D = 344 ± 226 m, respectively. “Silicate” objects have a much lower median Earth’s minimum orbit intersection distance (MOID) and a somewhat lower orbital inclination in comparison to “carbonaceous” objects. About half of the observed objects are potentially hazardous asteroids and are mostly (almost 65%) represented by “silicate” objects.
Published: 2021

13. Composition of inner main-belt planetesimals

Author: J. Bourdelle de Micas, S. Fornasier, C. Avdellidou, M. Delbo, G. van Belle, P. Ochner, W. Grundy, and N. Moskovitz
Subjects: Space and Planetary Science, Astronomy and Astrophysics
Abstract: Aims. We carried out a spectroscopic survey in order to investigate the composition of 64 asteroids of the inner main belt, which are leftovers of the original planetesimals of our Solar System (we call them inner main belt planetesimals or IMBPs). Following published methods, we identified IMBPs in the inverse size versus semimajor axis (α) space, after the removal of all asteroids belonging to collisional families. Methods. We conducted several ground-based observational campaigns of these IMBPs in the visible range at the 1.82 m Asiago telescope, and in the near-infrared range at the Telescopio Nationale Galileo, the Lowell Discovery Telescope, and the NASA InfraRed Telescope Facility telescopes. As several of the identified planetesimals already have spectra published in the literature, we collected all the available data and focused the telescope time to investigate those never observed before, or to complete the 0.45–2.5 μm range spectrum for those for which there is only partial spectral coverage or data with poor signal-to-noise ratio. In this way, we obtained new spectra for 24 IMBPs. Combining new and literature observations, we present spectra for 60 IMBPs in both the visible and near-infrared range, and 4 IMBPs in the visible only. All spectra were classified following well-established taxonomies. We also characterized their spectral absorption bands – when present –, their spectral slopes, and their mineralogy. In addition, we performed curve matching between astronomical and laboratory spectra in order to identify the closest meteorite analog using the RELAB database. Results. The majority of the IMBPs belong to the S-complex; the latter are best matched with ordinary chondrite meteorites, and their olivine/(olivine and pyroxene) abundance ratio is not correlated with the semi-major axis. This result does not support the hypothesis that this ratio increases with heliocentric distance. Furthermore, ~27% of the IMBPs belong to the C-complex, where Ch/Cgh types dominate, meaning that most of the carbonaceous-rich planetesimals were aqueously altered. These are best fitted by CM2 carbonaceous chondrite meteorites. Finally, the remaining IMBPs (~20%) belong to the X-complex, and have various mineralogies and meteorite matches, while a few are end-member classes, including L-, K-, V-, and D- or T-types. Conclusions. Our spectroscopic investigation of IMBPs confirms that silicate-rich bodies dominated the inner main belt where temperature has permitted the condensation of silicate rocks. However, almost all the spectral types are found, with the notable exception of olivine-rich A-types and Q-type asteroids. Their absence, as well as the absence of the R- and O-types among planetesimals, might be due to the rarity of these types among large asteroids. However, the absence of Q-types among primordial planetesimals is expected, as they have undergone surface rejuvenating processes. Therefore, Q-types have relatively young and less weathered surfaces compared to other types. Our results support the hypothesis of compositional mixing in the early Solar System. In particular, the fact that most of the C-complex planetesimals are aqueous altered, and the presence of three D- or T-type asteroids among them indicate that these bodies migrated from beyond 3 au to their current position.
Published: 2022

14. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

Author: F. Capaccioni, A. Coradini, G. Filacchione, S. Erard, G. Arnold, P. Drossart, M. C. De Sanctis, D. Bockelee-Morvan, M. T. Capria, F. Tosi, C. Leyrat, B. Schmitt, E. Quirico, P. Cerroni, V. Mennella, A. Raponi, M. Ciarniello, T. McCord, L. Moroz, E. Palomba, E. Ammannito, M. A. Barucci, G. Bellucci, J. Benkhoff, J. P. Bibring, A. Blanco, M. Blecka, R. Carlson, U. Carsenty, L. Colangeli, M. Combes, M. Combi, J. Crovisier, T. Encrenaz, C. Federico, U. Fink, S. Fonti, W. H. Ip, P. Irwin, R. Jaumann, E. Kuehrt, Y. Langevin, G. Magni, S. Mottola, V. Orofino, P. Palumbo, G. Piccioni, U. Schade, F. Taylor, D. Tiphene, G. P. Tozzi, P. Beck, N. Biver, L. Bonal, J.-Ph. Combe, D. Despan, E. Flamini, S. Fornasier, A. Frigeri, D. Grassi, M. Gudipati, A. Longobardo, K. Markus, F. Merlin, R. Orosei, G. Rinaldi, K. Stephan, M. Cartacci, A. Cicchetti, S. Giuppi, Y. Hello, F. Henry, S. Jacquinod, R. Noschese, G. Peter, R. Politi, J. M. Reess, and A. Semery
Published: 2015
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15. First light of SOVAG, a spectrograph for visible and near-infrared observation of asteroids

Author: A. Nedelcu, J. Dubois, François Colas, S. Fornasier, Benoit Carry, Pascal Morfin, Mirel Birlan, David Darson, Pierre Vernazza, F. Cochard, D. Perna, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Near-infrared spectroscopy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, First light, 01 natural sciences, law.invention, Telescope, Phase angle (astronomy), Space and Planetary Science, Observatory, Asteroid, law, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Spectrograph, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract: Spectroscopy in the visible and near-infrared has been the main tool for characterising the surface properties of asteroids for decades. For a given target, the two wavelength regimes are usually acquired by different telescopes/instruments, separated by years. They are seldom obtained simultaneously. However, it is not straightforward to combine datasets from different sources because of the spectral reddening linked with phase angle. We present the first-light result of SOVAG (Spectrographe pour l’Observations dans le Visible et infrarouge proche d’Asteroides Geocroiseurs), a new concept of spectrograph for observing both wavelength ranges at the same time. It is compact in design and portable. We developed a prototype of this instrument between 2016 and 2018. In July 2018, we mounted SOVAG on the 1 m-telescope in Pic du Midi observatory (for which it was designed) and conducted its on-sky first light experiment. We present a spectrum of (4) Vesta which demonstrates the reliability of observations and the accuracy of the calibration. Ongoing development will allow us to push observation-limits toward fainter objects.
Published: 2021

16. In search of Bennu analogs: Hapke modeling of meteorite mixtures

Author: S. Fornasier, Beth E. Clark, F. Merlin, M. A. Barucci, P. H. Hasselmann, J. D. P. Deshapriya, V. E. Hamilton, Dante S. Lauretta, D. C. Reuter, A. Praet, Devin L. Schrader, Amy Simon, X. D. Zou, J. Y. Li, Centre d'études et de recherches sur les qualifications (CEREQ), ministère de l'Emploi, cohésion sociale et logement-Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Observatorio Nacional [Rio de Janeiro], Ithaca College, Southwest Research Institute [Boulder] (SwRI), NASA Goddard Space Flight Center (GSFC), Planetary Science Institute [Tucson] (PSI), Université Grenoble Alpes - UFR Arts & Sciences Humaines (UGA UFR ARSH), Université Grenoble Alpes (UGA), LAboratoire de Recherche Historique Rhône-Alpes - UMR5190 (LARHRA), École normale supérieure de Lyon (ENS de Lyon)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Center for Meteorite Studies [Tempe], Arizona State University [Tempe] (ASU), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and École normale supérieure - Lyon (ENS Lyon)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML)
Subjects: Physics, 010504 meteorology & atmospheric sciences, Infrared spectroscopy, Astronomy and Astrophysics, Context (language use), Astrophysics, 01 natural sciences, methods: data analysis, Spectral line, Characterization (materials science), Absorbance, Meteorite, 13. Climate action, Space and Planetary Science, Chondrite, Asteroid, 0103 physical sciences, minor planets, asteroids: individual: (101955) Bennu, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, techniques: spectroscopic, 0105 earth and related environmental sciences
Abstract: Context.The OSIRIS-REx Visible and InfraRed Spectrometer onboard the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer spacecraft obtained many spectra from the surface of the near-Earth asteroid (101955) Bennu, enabling the characterization of this primitive small body. Bennu is spectrally similar to the hydrated carbonaceous chondrites (CCs), but questions remain as to which CCs, or combinations thereof, offer the best analogy to its surface.Aims.We aim to understand in more detail the composition and particle size of Bennu’s surface by refining the relationship between this asteroid and various CC meteorites.Methods.We used published absorbance and reflectance data to identify new optical constants for various CC meteorites measured in the laboratory at different temperatures. We then used the Hapke model to randomly generate 1000 synthetic spectra in order to find the combinations of these potential meteoritic analogs that best reproduce the spectral features of the asteroid.Results.Our investigations suggest that the surface of Bennu, though visibly dominated by boulders and coarse rubble, is covered by small particles (tens to a few hundreds of μm) and that possibly dust or powder covers the larger rocks. We further find that the surface is best modeled using a mixture of heated CM, C2-ungrouped, and, to some extent, CI materials.Conclusions.Bennu is best approximated spectrally by a combination of CC materials and may not fall into an existing CC group.
Published: 2021

17. Author Correction: Shape of (101955) Bennu indicative of a rubble pile with internal stiffness

Author: M. Lefevre, Aaron S. Burton, Carina Bennett, J. A. Mapel, Renu Malhotra, Peter Fleming, J. McAdams, N. Mogk, R. L. Ballouz, P. H. Smith, V. Nifo, C. K. Maleszewski, Timothy D. Swindle, E. Dotto, Stephen R. Schwartz, C. May, J. Bayron, D. Patterson, D. Guevel, Ellen S. Howell, Humberto Campins, J. Kissell, E. Brown, J. Wood, E. Muhle, John Robert Brucato, J. Small, B. Miller, Oleksiy Golubov, R. Pennington, K. Harshman, J. Nelson, Catherine Elder, M. McGee, R. Burns, J. Contreras, S. Hull, D. Kubitschek, D. Noss, Andrew J. Liounis, J. Backer, B. May, G. Fitzgibbon, J. Donaldson, D. Worden, Bashar Rizk, R. Witherspoon, Catherine L. Johnson, Erica Jawin, G. Shaw, A. Aqueche, Dolores H. Hill, D. Folta, S. Ferrone, M. Lujan, Giovanni Poggiali, B. G. Williams, S. Selznick, Melissa A. Morris, K. Rios, Sara S. Russell, D. Lambert, J. Hong, Jeffrey B. Plescia, H. Bloomenthal, D. Drinnon, Olivier S. Barnouin, Derek S. Nelson, Amanda E. Toland, Michael C. Moreau, J. A. Seabrook, K. Dill, A. Mirfakhrai, K. Hyde, J. D. P. Deshapriya, Hannah Kaplan, Timothy P. McElrath, Juliette I. Brodbeck, N. Ramos, S. Stewart, James B. Garvin, Sei-ichiro Watanabe, M. Arvizu-Jakubicki, Jason P. Dworkin, Matthew A. Siegler, Collin Lewin, Masatoshi Hirabayashi, L. Bloomquist, S. Gardner, Keiko Nakamura-Messenger, A. H. Nair, M. Schmitzer, P. Haas, Julie Bellerose, Dolan E. Highsmith, L. Koelbel, C. C. Lorentson, J. Zareski, E. Queen, S. R. Chesley, Philip A. Bland, A. Cheuvront, V. E. Hamilton, Ronald G. Mink, N. Mastrodemos, H. C. Connolly, K. Bellamy, M. Killgore, A. Gardner, Y. Takahashi, M. Lambert, R. C. Espiritu, Z. Zeszut, E. T. Morton, Kevin J. Walsh, Timothy D. Glotch, M. Skeen, Brian Kennedy, Matthew R.M. Izawa, G. Neumann, F. Teti, D. Doerres, A. Hasten, F. Ciceri, D. Howell, A. Deguzman, J. Nagy, D. Vaughan, H. Ma, C. Lantz, D. N. Brack, David K. Hammond, Erwan Mazarico, Leilah K. McCarthy, L. Rhoads, Kathleen L. Craft, C. Welch, Jay W. McMahon, C. L. Parish, D. C. Reuter, M. Giuntini, N. Castro, Clive Dickinson, J. Kreiner, K. Kingsbury, S. Dickenshied, Joseph A. Nuth, Alan R. Hildebrand, Erik Asphaug, H. Ido, Eric M. Sahr, A. Harbison, Arlin E. Bartels, T. Forrester, D. Eckart, R. Bandrowski, Michael K. Barker, Robert Gaskell, J. Wendel, S. Freund, Marc Bernacki, Ryan S. Park, A. Taylor, E. B. Bierhaus, S. Millington-Veloza, J. Stromberg, L. B. Breitenfeld, K. Stakkestad, D. Ellis, Timothy J. McCoy, M. Susak, Richard G. Cosentino, C. Manzoni, Hisayoshi Yurimoto, C. Drouet d'Aubigny, A. Bjurstrom, Masako Yoshikawa, S. Francis, J. Peachey, J. Geeraert, K. Marchese, O. Billett, M. Rascon, F. Jaen, B. Diallo, Martin Miner, Kris J. Becker, E. Mazzotta Epifani, Florian Thuillet, A. Knight, James H. Roberts, Pasquale Tricarico, Edward A. Cloutis, T. Fisher, Dale Stanbridge, A. Colpo, Osiris-Rex Team, S. Gonzales, Q. Tran, M. K. Crombie, John Marshall, N. Bojorquez-Murphy, David Vokrouhlický, Allen W. Lunsford, H. Bowles, K. L. Edmundson, R. A. Masterson, Peter G. Antreasian, N. Gorius, Benjamin Rozitis, D. Pino Muñoz, S. Carlson-Kelly, C. Thayer, J. Elsila Cook, B. C. Clark, N. Piacentine, José C. Aponte, M. Al Asad, M. A. Barucci, D. Blum, P. Falkenstern, Neil Bowles, Matthew Chojnacki, J. M. Leonard, J. Daly, K. Yetter, M. R. Fisher, Jeffrey N. Grossman, A. Boggs, N. Jayakody, Cristina A. Thomas, C.M. Ernst, Namrah Habib, J. N. Kidd, R. J. Steele, Andrew B. Calloway, Andrew Ryan, Kimberly T. Tait, Paul O. Hayne, J. Y. Li, K. L. Berry, William V. Boynton, Yanga R. Fernandez, D. A. Lorenz, M. Wasser, Daniel J. Scheeres, K. Fortney, A. Scroggins, B. Allen, B. Sutter, T. Ferro, Jonathan Joseph, Derek C. Richardson, D. Hoak, Brian Carcich, W. Chang, P. Wren, C. Boyles, Kaj E. Williams, B. Marty, J. Liang, J. Hoffman, A. Harch, Daniel R. Wibben, Jamie Molaro, S. Rieger, R. Enos, C. W. Hergenrother, Stephen R. Sutton, J. Grindlay, E. J. Lessac-Chenen, E. Huettner, C. Norman, P. Sherman, L. Swanson, M. Coltrin, S. Van wal, B. Buck, A. Fisher, Kevin Righter, Brian Rush, David D. Rowlands, Lauren McGraw, A. Levine, K. Drozd, D. Gaudreau, A. Nguyen, S. Sides, M. Chodas, R. Dubisher, B. Ashman, Michael Caplinger, Amy Simon, W. Moore, S. S. Balram-Knutson, R. Carpenter, S. Fornasier, Shogo Tachibana, Russell Turner, Ian A. Franchi, Trevor Ireland, Chloe B. Beddingfield, D. F. Everett, M. Corvin, Lindsay P. Keller, Tammy L. Becker, S. Carter, J. L. Rizos Garcia, Mark E. Perry, E. Keates, Michael C. Nolan, P. Vasudeva, C. Fellows, K. Herzog, Mark A. Jenkins, J. R. Weirich, J. Swenson, D. R. Golish, Davide Farnocchia, Lydia C. Philpott, Rebecca R. Ghent, Hannah C.M. Susorney, S. W. Squyres, Pedro Hasselmann, J. Hill, Thomas J. Zega, B. Key, Marco Delbo, A. S. French, P. Sánchez, A. Hilbert, J. Y. Pelgrift, R. P. Binzel, L. McNamara, Vishnu Reddy, Michael Daly, Scott Messenger, Daniella DellaGiustina, Maurizio Pajola, Charles Brunet, Joshua L. Bandfield, J. Padilla, A. Janakus, M. Moreau, R. Garcia, R. A. Chicoine, P. Michel, P. Kaotira, K. S. Johnson, J. Forelli, G. Miller, K. Martin, I. Galinsky, S. Desjardins, Naru Hirata, Christine Hartzell, M. L. Jones, S. Hooven, D. Velez, R. Munoz, Carolyn M. Ernst, C. Emr, N. Martinez-Vlasoff, S. Bendall, R. Zellar, E. Church, Theodore Kareta, T. Warren, P. Wolff, V. Morrison, C. Bryan, S. Bhaskaran, N. Jones, D. Hauf, Jeremy Bauman, R. T. Daly, R. Olds, M. M. Westermann, D. K. Hamara, E. Audi, G. Johnston, Eric Palmer, Courtney Mario, Daniel P. Glavin, T. Haltigin, J. Cutts, Javier Licandro, Xiao-Duan Zou, H. L. Roper, Gregory A. Neumann, William M. Owen, S. Sugita, Y. H. Tang, Kevin Burke, H. L. Enos, D. Gallagher, William F. Bottke, K. Getzandanner, Philip R. Christensen, C. W. V. Wolner, K. Fleshman, D. Poland, J. P. Emery, M.M. Riehl, D. Fennell, D. Sallitt, A. D. Rogers, M. Fitzgibbon, John H. Jones, S. Mullen, S. Salazar, S. Oliver, A. T. Polit, J. Cerna, A. Praet, Mark E. Holdridge, E. M. Ibrahim, Coralie D. Adam, J. de León, Christopher J. Miller, M. Ryle, J. Lyzhoft, M. Loveridge, C. Hoekenga, Brent J. Bos, S. Anwar, K. Chaffin, Devin L. Schrader, B. Lovelace, Romy D. Hanna, C. D. Adam, G. L. Mehall, K. L. Donaldson Hanna, F. Merlin, B. Wright, Guy Libourel, L. F. Lim, N. Shultz, Dante S. Lauretta, K. Hanley, Beth E. Clark, L. Le Corre, K. Thomas-Keprta, Moses Milazzo, W. Hagee, B. Page, M. Fisher, E. McDonough, D. Trang, S. Clemett, A. Rubi, A. Ingegneri, Scott A. Sandford, D. Dean, J. Freemantle, Michael D. Smith, Christopher W. Haberle, L. Nguyen, M. Fulchignoni, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL), Centre de Mise en Forme des Matériaux (CEMEF), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Rubble, Stiffness, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, [SDU]Sciences of the Universe [physics], engineering, medicine, General Earth and Planetary Sciences, Geotechnical engineering, medicine.symptom, Pile, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience
Published: 2020

18. Pronounced morphological changes in a southern active zone on comet 67P/Churyumov-Gerasimenko

Author: Pedro Hasselmann, Giampiero Naletto, Carsten Güttler, Horst Uwe Keller, Detlef Koschny, Philippe Lamy, J. M. Sunshine, J. D. P. Deshapriya, L. M. Lara, Francesco Marzari, M. De Cecco, S. Fornasier, R. Rodrigo, Holger Sierks, V. Da Deppo, Monica Lazzarin, G. Cremonese, Marco Fulle, Ivano Bertini, Björn Davidsson, Dennis Bodewits, P. J. Gutierrez, Cecilia Tubiana, Stefano Debei, Van H. Hoang, Xian Shi, M. A. Barucci, W-H. Ip, Clement Feller, J.-L. Bertaux, Dominique Bockelée-Morvan, J. J. Lopez-Moreno, Jakob Deller, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institute of Physics [Hanoi], Vietnam Academy of Science and Technology (VAST), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Planetary Science Institute [Tucson] (PSI), University of Trento [Trento], ANR-17-CE31-0004,CLASSY,Composition des surfaces du Système Solaire de bas albédo(2017), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), IMPEC - LATMOS, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA)-European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and California Institute of Technology (CALTECH)-NASA
Subjects: 67P/Churyumov-Gerasimenko - methods, 010504 meteorology & atmospheric sciences, Comet, Individual, Astrophysics, Fault scarp, 01 natural sciences, Indirect evidence, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, High spatial resolution, Comets, Active zone, miscellaneous [methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Miscellaneous, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Geodesy, 13. Climate action, Space and Planetary Science, methods: miscellaneous, Falling (sensation), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Production rate
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., A smooth deposit in the southern Khonsu region has been seen in ESA/Rosetta observations as active during the second half of 2015, when the southern summer coincided with the perihelion passage of 67P/Churyumov-Gerasimenko (67P). Image color sequences acquired by the OSIRIS instrument in the period of January 2015 to July 2016, pre- and post-perihelion, show the occurrence of several small transient events as well as three massive outbursts (-10 to 1500 tons). High spatial resolution images taken one year and a half apart allowed us to track a variety of sources: the formation of cavities that are 1.3-14 m deep, ice-enriched patches, scarp retraction, and a second 50 m-wide boulder. We then estimated their masses and the dust mass of their corresponding plumes and outbursts. In particular, the deformation left by that boulder and its lack of talus may provide evidence for the lifting and subsequent falling back to the surface of large blocks. We calculate that a minimum vapor production rate of 1.4 x 10(24) m(-2) s(-1) is required to lift such an object. The comparison of the masses that are lost in the new cavities to the dust mass of outbursts gives indirect evidence of highly volatile ice pockets underneath. The spectrophotometric analysis and boulder counting also provides evidence for cavities that formed only 30 m apart with different spectral slopes, two long-standing ice patches, and local variations in the boulder-size frequency distribution. All this points to sub-surface ice pockets with different degrees of depth. Finally, the total mass of the morphological changes compared to most recent calculations of the total released mass by activity on 67P is estimated to be between 1.5 and 4.2%. This means that as many as about 25 similar active zones across the nucleus would be enough to sustain the entire cometary activity.© P. H. Hasselmann et al. 2019, P.H.H. would like to thank Alice Bernard for her support. This work was funded by the DIM-ACAV project (Ile-de-France). OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We acknowledge the financial support from the France Agence Nationale de la Recherche (programme Classy, ANR-17-CE31-0004).
Published: 2019

19. The backscattering ratio of comet 67P/Churyumov-Gerasimenko dust coma as seen by OSIRIS onboard Rosetta

Author: Pamela Cambianica, F. La Forgia, Jean-Loup Bertaux, P. J. Gutierrez, Alice Lucchetti, E. Frattin, Alessandra Rotundi, Detlef Koschny, Pedro Hasselmann, Xian Shi, Wing-Huen Ip, Giovanna Rinaldi, Philippe Lamy, Carsten Güttler, Giampiero Naletto, Stefano Mottola, Monica Lazzarin, Marco Fulle, J. J. Lopez Moreno, Sabrina Ferrari, Nafiseh Masoumzadeh, M. A. Barucci, H. U. Keller, D. Guirado, Imre Toth, V. Petropoulou, Gábor L. Kovács, Holger Sierks, Gabriele Cremonese, M. De Cecco, Cesare Barbieri, L. M. Lara, Björn Davidsson, Jakob Deller, Dennis Bodewits, S. Ivanovsky, Francesca Ferri, Cecilia Tubiana, Luca Penasa, Jessica Agarwal, Stefano Debei, Ivano Bertini, Maurizio Pajola, Olga Muñoz, Francesco Marzari, S. Fornasier, Matteo Massironi, F. Moreno, R. Rodrigo, V. Da Deppo, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Ministerio de Educación y Ciencia (España), Swedish National Space Agency, European Space Agency, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], INAF - Osservatorio Astronomico di Padova (OAPD), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Physics [Auburn], Auburn University (AU), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Dipartimento di Geoscienze [Padova], Fulle, M. [0000-0001-8435-5287], Tubiana, C. [0000-0001-8475-9898], Güttler, C. [0000-0003-4277-1738], Pajola, M. [0000-0002-3144-1277], Rinaldi, G. [0000-0002-2968-0455], Naletto, G. [0000-0003-2007-3138], Barucci, M. A. [0000-0002-1345-0890], Bertaux, J. L. [0000-0003-0333-229X], Deller, J. [0000-0001-8341-007X], Fornasier, S. [0000-0001-7678-3310], Penasa, L. [0000-0002-6394-3108], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA), and Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Subjects: 67P/Churyumov-Gerasimenko, Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, photometry, Comet, data analysis, scattering –methods: data analysis – techniques: image processing – techniques: photometric – comets: individual: 67P/Churyumov-Gerasimenko, techniques: image processing, Astrophysics, 01 natural sciences, Photometry (optics), Scattering, techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Churyumov–Gerasimenko, image processing [Techniques], data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], scattering, methods: data analysis, techniques: image processing, techniques: photometric, comets: individual: 67P/Churyumov-Gerasimenko, Phase angle, scattering, photometric [Techniques], comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, biology.organism_classification, methods: data analysis, image processing, 13. Climate action, Space and Planetary Science, Drag, Temporal resolution, Inverse scattering problem, Osiris, individual: 67P [Comets], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Remote sensing observations of dust particles ejected from comets provide important hints on the intimate nature of the materials composing these primitive objects. The measurement of dust coma backscattering ratio, BSR, defined as the ratio of the reflectance at phase angle 0 ◦ and 30 ◦ , helps tuning theoretical models aimed at solving the inverse scattering problem deriving information on the nature of the ejected particles. The Rosetta/OSIRIS camera sampled the coma phase function of comet 67P, with four series acquired at low phase angles from 2015 January to 2016 May. We also added previously published data to our analysis to increase the temporal resolution of our findings. We measured a BSR in the range ∼ [1.7-3.6], broader than the range found in literature from ground-based observations of other comets. We found that during the post-perihelion phase, the BSR is systematically larger than the classical cometary dust values only for nucleocentric distances smaller than ∼ 100 km. We explain this trend in terms of a cloud of chunks orbiting the nucleus at distances < 100 km ejected during perihelion and slowly collapsing on the nucleus over a few months because of the coma gas drag. This also implies that the threshold particle size for the dust phase function to become similar to the nucleus phase function is between 2.5 mm and 0.1 m, taking into account previous Rosetta findings. © 2018 The Author(s)., The support of the national funding agencies of Germany (DLR: Deutschen Zentrums fur Luft-und Raumfahrt), France (CNES: Centre national d' etudes spatiales), Italy (ASI: Agenzia Spaziale Italiana), Spain (MEC: Ministry of Education& Science), Sweden (SNSB: Swedish National Space Board), and the European Space Agency (ESA) Technical Directorate is gratefully acknowledged.
Published: 2019

20. Quantitative analysis of isolated boulder fields on comet 67P/Churyumov-Gerasimenko

Author: Philippe Lamy, G. Cremonese, W.-H. Ip, Pamela Cambianica, Marco Fulle, Sabrina Ferrari, Dennis Bodewits, Matteo Massironi, Alice Lucchetti, Frank Scholten, Jean-Loup Bertaux, P. J. Gutierrez, F. La Forgia, Björn Davidsson, Francesco Marzari, Carsten Güttler, Z. Y. Lin, Jakob Deller, Cecilia Tubiana, Ivano Bertini, Detlef Koschny, M. De Cecco, Monica Lazzarin, M. A. Barucci, Holger Sierks, Emanuele Simioni, H. U. Keller, S. Fornasier, R. Rodrigo, Stefano Debei, L. M. Lara, V. Da Deppo, Xian Shi, Stefano Mottola, J.-B. Vincent, Giampiero Naletto, Luca Penasa, Maurizio Pajola, Imre Tóth, J. J. Lopez-Moreno, Cambianica, P. [https://orcid.org/0000-0002-8091-4915], European Space Agency (ESA), Centre National D'Etudes Spatiales (CNES), Agencia Estatal de Investigación (AEI), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Agenzia Spaziale Italiana (ASI), Swedish National Space Agency (SNSA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Dipartimento di Geoscienze [Padova], Department of Physics [Auburn], Auburn University (AU), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comets, Data analysis, General, Individual, Methods, Population, Comet, Narrow angle, Geometry, Astrophysics, 01 natural sciences, Power law, Fractal, individual: 67P/Churyumov-Gerasimenko [Comets], Power index, 0103 physical sciences, education, data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Comets: individual: 67P/Churyumov-Gerasimenko, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], general [Comets], Astronomy and Astrophysics, methods: data analysis, Comets: general, Space and Planetary Science, Spatial ecology, comets: general – comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis, Sublimation (phase transition), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We provide a detailed quantitative analysis of isolated boulder fields situated in three different regions of comet 67P/Churyumov-Gerasimenko: Imhotep, Hapi, and Hatmehit. This is done to supply a useful method for analyzing the morphology of the boulders and to characterize the regions themselves. Methods. We used OSIRIS Narrow Angle Camera images with a spatial scale smaller than 2 mpx(-1) and analyzed the size-frequency distribution and the cumulative fractional area per boulder population. In addition, we correlated shape parameters, such as circularity and solidity, with both the spatial and the size-frequency distribution of the three populations. Results. We identified 11 811 boulders in the Imhotep, Hapi, and Hatmehit regions. We found that the Hatmehit and Imhotep areas show power indices in the range of -2.3/-2.7. These values could represent a transition between gravitational events caused by thermal weathering and sublimation, and material formed during collapses that has undergone sublimation. The Hapi area is characterized by a lower power index (-1.2/-1.7), suggesting that those boulders have a different origin. They can be the result of material formed during gravitational events and collapses that has undergone continuous fragmentation. We calculated the cumulative fractional area (CFA) in order to investigate how the area is covered by boulders as a function of their sizes. The Hatmehit and Imhotep regions show a CFA that is well fit by a power law. In contrast, the Hapi area does not show the same trend. We analyzed the fractal distributions, finding that the populations seem to be fractal at all dimensions, except for the Hapi distribution, which shows a possible fractal behavior for small dimensions only. Finally, the average values of the shape parameters reveal solid and roundish boulders in all populations we studied.© ESO 2019, OSIRIS was built by a consortium of the Max-Planck Institut fur Sonnensystemforschung, in Guttingen, Germany, CISAS University of Padova, Italy, the Laboratoire de Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC and ESTEC for their work in support of the Rosetta mission. We made use of Arcgis 10.3.1 software together with the Matlab, Java, and ImageJ software to perform our analysis. I thank Frederic Moisy for sharing the box-count work.
Published: 2019

21. On deviations from free-radial outflow in the inner coma of comet 67P/Churyumov–Gerasimenko

Author: Olivier Groussin, Björn Davidsson, Giampiero Naletto, S. Fornasier, Cecilia Tubiana, Horst Uwe Keller, P. L. Lamy, Michael Küppers, J.F. Wu, Hans Rickman, M. A. Barucci, W-H. Ip, Ekkehard Kührt, Stubbe F. Hviid, Selina-Barbara Gerig, L. M. Lara, C. C. Su, Marco Fulle, Nilda Oklay, R. Rodrigo, Monica Lazzarin, Stefano Mottola, Jean-Baptiste Vincent, V. Da Deppo, Laurent Jorda, Jörg Knollenberg, P. J. Gutierrez, Stefano Debei, Frank Scholten, G. Cremonese, M. De Cecco, Holger Sierks, Frank Preusker, J. L. Bertaux, Cesare Barbieri, Jakob Deller, Raphael Marschall, Dennis Bodewits, J. J. Lopez Moreno, Ivano Bertini, Detlef Koschny, Nicolas Thomas, Carsten Güttler, Jessica Agarwal, Imre Tóth, Francesco Marzari, J.-R. Kramm, Swiss National Science Foundation, European Commission, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universität Bern [Bern], Institute of Space Science [Taiwan], Max-Planck-Institut für Sonnensystemforschung (MPS), Max Planck Institute for Solar System Research (MPS), DLR Institute of Planetary Research, German Aerospace Center (DLR), University of Bern (UBERN), International Space Science Institute (ISSI), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Department of Astronomy, University of Maryland, Jet Propulsion Laboratory, California Institute of Technology (JPL), INAF - Osservatorio Astronomico, Via Tiepolo 11, 34014 Trieste, Italy, Graduate Institute of Astronomy, Institute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Science Operations Department, European Space Astronomy Centre/ESA, P.O. Box 78, 28691 Villanueva de la Canada, Madrid, Spain, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics, National Tsing Hua University, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Gottingen, Germany, Department of Physics and Astronomy, University of Padova, Vicolo dell'Osservatorio 3, 35122 Padova, Italy, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Space Research Center, Polish Academy of Sciences (Warsaw), Observatoire de Paris, Université Paris sciences et lettres (PSL), CNR-IFN UOS Padova LUXOR, Università di Trento (UNITN), Instituto de Astrofisica de Andalucia, CSIC (IAA), Dipartimento di Fisica, Università di Padova, Universita degli Studi di Padova, California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Technische Universität Braunschweig [Braunschweig], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)
Subjects: 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Infrared, 67P/Churyumov–Gerasimenko, Astrophysics, Dust, Inner coma, OSIRIS, Rosetta, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Magnetosphere particle motion, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Particle acceleration, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Outflow, Direct simulation Monte Carlo, Astrophysics::Earth and Planetary Astrophysics, Test particle, Impact parameter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed. For commercial reuse, permission must be requested below., The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard the European Space Agency's Rosetta spacecraft acquired images of comet 67P/Churyumov–Gerasimenko (67P) and its surrounding dust coma starting from May 2014 until September 2016. In this paper we present methods and results from analysis of OSIRIS images regarding the dust outflow in the innermost coma of 67P. The aim is to determine the global dust outflow behaviour and place constraints on physical processes affecting particles in the inner coma. We study the coma region right above the nucleus surface, spanning from the nucleus centre out to a distance of about 50 km comet centric distance (approximately 25 average comet radii). We primarily adopt an approach used by Thomas and Keller (1990) to study the dust outflow. We present the effects on azimuthally-averaged values of the dust reflectance of non-radial flow and non-point-source geometry, acceleration of dust particles, sublimation of icy dust particles after ejection from the surface, dust particle fragmentation, optical depth effects and the influence of gravitationally bound particles. All of these physical processes could modify the observed distribution of light scattered by the dust coma. In the image analysis, profiles of azimuthally averaged dust brightness as a function of impact parameter b (azimuthal average, “Ā-curve”) were fitted with a simple function that best fits the shape of our profile curves (f(b;u,v,w,z)=u/b+wb+z). The analytical fit parameters (u, v, w, z), which hold the key information about the dust outflow behaviour, were saved in a comprehensive database. Through statistical analysis of these information, we show that the spatial distribution of dust follows free-radial outflow behaviour (i.e. force-free radial outflow with constant velocity) beyond distances larger than ∼11.9 km from the comet centre, which corresponds to a relative distance of about 6 average comet radii from the comet centre. Hence, we conclude that beyond this distance, and on average, fragmentation and gravitationally bound particles are negligible processes in determining the optically scattered light distribution in the innermost coma. Closer to the nucleus we observe dust outflow behaviour that deviates from free-radial outflow. A comparison of our result profiles with numerical models using a Direct Simulation Monte Carlo (DSMC) approach with dust particle distributions calculated using a test particle approach has been used to demonstrate the influence of a complex shape and particle acceleration on the azimuthal average profiles. We demonstrate that, while other effects such as fragmentation or sublimation of dust particles cannot be ruled out, acceleration of the dust particles and effects arising from the shape of the irregular nucleus (non-point source geometry) are sufficient to explain the observed dust outflow behaviour from image data analysis. As a by-product of this work, we have calculated “Afρ” values for the 1/r regime. We found a peak in the coma activity in terms of Afρ (normalised to a phase angle of 90°) of ∼210 cm 20 days after perihelion. Furthermore, based on simplified models of particle motion within bound orbits, it is shown that limits on the total cross-sectional area of bound particles might be derived through further analysis. An example is given. © 2018 The Authors, The team from the University of Bern is supported through the Swiss National Science Foundation and through the NCCR PlanetS. The project has also received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2. The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.
Published: 2018

22. Models of Rosetta/OSIRIS 67P Dust Coma Phase Function

Author: Giovanna Rinaldi, Jean-Loup Bertaux, Carsten Güttler, Marco Fulle, Xian Shi, Giampiero Naletto, Jessica Agarwal, Stefano Mottola, Dominique Bockelée-Morvan, Olga Muñoz, Holger Sierks, F. Moreno, V. V. Zakharov, Francesco Marzari, M. De Cecco, V. Della Corte, Stavro Ivanovski, E. Frattin, Detlef Koschny, L. M. Lara, Björn Davidsson, Cecilia Tubiana, Wing-Huen Ip, Philippe Lamy, Ivano Bertini, S. Fornasier, H. U. Keller, Ludmilla Kolokolova, Monica Lazzarin, Gabriele Cremonese, J. J. López-Moreno, Alessandra Rotundi, Dennis Bodewits, Stefano Debei, Imre Tóth, D. Guirado, P. J. Gutierrez, Jakob Deller, Zhong-Yi Lin, M. A. Barucci, R. Rodrigo, V. Da Deppo, Polish Academy of Sciences, Ministerio de Economía y Competitividad (España), European Commission, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), National Central University [Taiwan] (NCU), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), and Technische Universität Braunschweig [Braunschweig]
Subjects: methods: numerical, minor planets, asteroids: individual (67P/Churyumov-Gerasimenko), Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Library science, FOS: Physical sciences, 7. Clean energy, 01 natural sciences, 0103 physical sciences, Phase function, asteroids: individual (67P/Churyumov-Gerasimenko), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, asteroids: individual (67P), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Mission operations, numerical [Methods], biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], asteroids: individual (67P Churyumov–Gerasimenko), biology.organism_classification, individual (67P/Churyumov-Gerasimenko) [Minor planets,asteroids], minor planets, Astrophysics::Earth and Planetary Astrophysics, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Minor planets,asteroids: individual (67P/Churyumov-Gerasimenko), Astrophysics - Earth and Planetary Astrophysics
Abstract: The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images. This function shows a deep minimum at phase angles near 100°, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly oriented aggregate particles. We show, however, that an ensemble of oriented elongated particles of a wide variety of aspect ratios, with radii r 10 μm, and whose long axes are perpendicular to the direction of the solar radiation, are capable of reproducing the observed phase function. These particles must be absorbing, with an imaginary part of the refractive index of about 0.1 to match the expected geometric albedo, and with porosity in the 60%-70% range.© 2018. The American Astronomical Society. All rights reserved.., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, in Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire dAstrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politecnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB; grant No. 74/10: 2), and the ESA Technical Directorate is gratefully acknowledged. H.R. was also supported by grant No. 2011/01/B/ST9/05442 of the Polish National Science Center. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC, and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. This work was supported by contracts AYA2015-67152-R and AYA2015-71975-REDT from the Spanish Ministerio de Economia y Competitividad.
Published: 2018

23. A three-dimensional modelling of the layered structure of comet 67P/Churyumov-Gerasimenko

Author: Hans Rickman, Matteo Massironi, J.-R. Kramm, Ivano Bertini, Stubbe F. Hviid, Francesco Marzari, P. J. Gutierrez, M. De Cecco, Emanuele Simioni, Ekkehard Kührt, L. M. Lara, Frank Scholten, Detlef Koschny, Cesare Barbieri, Maurizio Pajola, R. Rodrigo, V. Da Deppo, Jakob Deller, Frank Preusker, S. Fornasier, Monica Lazzarin, Jean-Baptiste Vincent, Giampiero Naletto, Francesca Ferri, Robert Gaskell, Jessica Agarwal, Wing-Huen Ip, J-C. Lee, Laurent Jorda, N. Thomas, M. A. Barucci, Björn Davidsson, Michael Küppers, Alice Lucchetti, M. F. A'Hearn, Clement Feller, Marc Hofmann, Cecilia Tubiana, Olivier Groussin, Stefano Debei, Gabriele Cremonese, Holger Sierks, Marco Fulle, Philippe Lamy, Sabrina Ferrari, J. J. Lopez Moreno, F. La Forgia, Nilda Oklay, Carsten Güttler, E. Frattin, Luca Penasa, J. L. Bertaux, H. U. Keller, Jörg Knollenberg, Xian Shi, Stefano Mottola, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Astronomia [Padova], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NASA Ames Research Center (ARC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Planetary Science Institute [Tucson] (PSI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Università degli Studi di Trento (UNITN), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Earth Sciences [Chung-Li City], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), DLR Institute of Planetary Research, German Aerospace Center (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Universita degli Studi di Padova-Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), and Universität Bern [Bern]
Subjects: 010504 meteorology & atmospheric sciences, Geometry, Concentric, Classification of discontinuities, 01 natural sciences, Layered structure, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Comets: general, Methods: data analysis, Physics, [PHYS]Physics [physics], comets: individual: 67P/Churyumov–Gerasimenko, comets: general, Astronomy and Astrophysics, Dimensional modeling, Ellipsoid, methods: data analysis, Lobe, medicine.anatomical_structure, Space and Planetary Science, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Free parameter
Abstract: International audience; We provide a three-dimensional model of the inner layered structure of comet 67P based on the hypothesis of an extended layering independently wrapping each lobe. A large set of terrace orientations was collected on the latest shape model and then used as a proxy for the local orientation of the surfaces of discontinuity which defines the layers. We modelled the terraces as a family of concentric ellipsoidal shells with fixed axis ratios, producing a model that is completely defined by just eight free parameters. Each lobe of 67P has been modelled independently, and the two sets of parameters have been estimated by means of non-linear optimization of the measured terrace orientations. The proposed model is able to predict the orientation of terraces, the elongation of cliffs, the linear traces observed in the Wosret and Hathor regions and the peculiar alignment of boulder-like features which has been observed in the Hapi region, which appears to be related to the inner layering of the big lobe. Our analysis allowed us to identify a plane of junction between the two lobes, further confirming the independent nature of the lobes. Our layering models differ from the best-fitting topographic ellipsoids of the surface, demonstrating that the terraces are aligned to an internal structure of discontinuities, which is unevenly exposed on the surface, suggesting a complex history of localized material removal from the nucleus.
Published: 2017

24. Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/OSIRIS images: The southern hemisphere (Corrigendum)

Author: Monica Lazzarin, Laurent Jorda, J. B. Vincent, Cesare Barbieri, N. Thomas, Lorenza Giacomini, Olivier Groussin, S. Fornasier, Simone Marchi, B. J. R. Davidsson, A. Gracia-Berná, Antoine Pommerol, G. Cremonese, A. T. Auger, Raphael Marschall, Detlef Koschny, Matteo Massironi, P. J. Gutierrez, Stubbe F. Hviid, Holger Sierks, Cecilia Tubiana, Michael Küppers, F. Scholten, R. Rodrigo, Maurizio Pajola, N. Oklay, Mohamed Ramy El-Maarry, Ivano Bertini, J. J. Lopez Moreno, Géza Kovács, Hans Rickman, M. A. Barucci, W-H. Ip, J.-R. Kramm, Marco Fulle, P. L. Lamy, M. De Cecco, V. Da Deppo, Sebastien Besse, F. Preusker, Carsten Güttler, Giampiero Naletto, Francesco Marzari, H. U. Keller, M. F. A'Hearn, J. L. Bertaux, J.-C. Lee, Dennis Bodewits, Jörg Knollenberg, E. Kuehrt, L. M. Lara, Stefano Debei, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), NASA Ames Research Center (ARC), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), ESA Scientific Support Office, Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Università degli Studi di Trento (UNITN), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), Department of Information Engineering [Padova] (DEI), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Universität Bern [Bern], Universita degli Studi di Padova, European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universita degli Studi di Padova-Universita degli Studi di Padova, Max Planck Institute for Solar System Research (MPS), and California Institute of Technology (CALTECH)-NASA
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, 530 Physics, Comet, 01 natural sciences, Astrobiology, 0103 physical sciences, Rosetta, comets, OSIRIS, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, biology, 520 Astronomy, Planetengeodäsie, Astronomy, Astronomy and Astrophysics, 500 Science, biology.organism_classification, 620 Engineering, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience
Published: 2017

25. 'TNOs are Cool': A survey of the trans-Neptunian region: XII. Thermal light curves of Haumea, 2003 VS 2 and 2003 AZ 84 with Herschel/PACS

Author: Esa Vilenius, Olivier Groussin, Cs. Kiss, J. A. Stansberry, Rene Duffard, J. L. Ortiz, T. Mueller, S. Fornasier, Pedro Lacerda, Audrey Thirouin, Pablo Santos-Sanz, E. Lellouch, Laurent Jorda, European Commission, Ministerio de Industria y Competitividad (España), Junta de Andalucía, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia s/n, 18008, Granada, Spain, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Astrophysics Research Centre, Queen's University Belfast, Max-Planck-Institut für Extraterrestriche Physik (MPE), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Space Telescope Science Institute (STScI), Université Paris Diderot, Sorbonne Paris Cité, Paris, France, Université Paris Diderot - Paris 7 (UPD7), and Lowell Observatory, Flagstaff
Subjects: Solar System, 010504 meteorology & atmospheric sciences, individual: 2003 VS2 [Kuiper belt objects], Population, Dwarf planet, Haumea, Phase (waves), individual: 2003 AZ84 [Kuiper belt objects], Astrophysics, planetary systems [Infrared], 01 natural sciences, Submillimeter: planetary systems, Infrared: planetary systems, planetary systems [Submillimeter], 0103 physical sciences, Thermal, education, 010303 astronomy & astrophysics, Kuiper belt objects: individual: 2003 VS2, 0105 earth and related environmental sciences, Physics, education.field_of_study, individual: Haumea [Kuiper belt objects], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], photometric [Techniques], Astronomy and Astrophysics, Light curve, Space observatory, Kuiper belt objects: individual: Haumea, 13. Climate action, Space and Planetary Science, Kuiper belt objects: individual: 2003 AZ84, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Techniques: photometric
Abstract: Context. Time series observations of the dwarf planet Haumea and the Plutinos 2003 VS and 2003 AZ with Herschel/PACS are presented in this work. Thermal emission of these trans-Neptunian objects (TNOs) were acquired as part of the >TNOs are Cool> Herschel Space Observatory key programme. Aims. We search for the thermal light curves at 100 and 160 μm of Haumea and 2003 AZ, and at 70 and 160 μm for 2003 VS by means of photometric analysis of the PACS data. The goal of this work is to use these thermal light curves to obtain physical and thermophysical properties of these icy Solar System bodies. Methods. When a thermal light curve is detected, it is possible to derive or constrain the object thermal inertia, phase integral and/or surface roughness with thermophysical modeling. Results. Haumea's thermal light curve is clearly detected at 100 and 160 μm. The effect of the reported dark spot is apparent at 100 μm. Different thermophysical models were applied to these light curves, varying the thermophysical properties of the surface within and outside the spot. Although no model gives a perfect fit to the thermal observations, results imply an extremely low thermal inertia (0.73) for Haumea's surface. We note that the dark spot region appears to be only weakly different from the rest of the object, with modest changes in thermal inertia and/or phase integral. The thermal light curve of 2003 VS is not firmly detected at 70 μm and at 160 μm but a thermal inertia of (2 ± 0.5) MKS can be derived from these data. The thermal light curve of 2003 AZ is not firmly detected at 100 μm. We apply a thermophysical model to the mean thermal fluxes and to all the Herschel/PACS and Spitzer/MIPS thermal data of 2003 AZ, obtaining a close to pole-on orientation as the most likely for this TNO. Conclusions. For the three TNOs, the thermal inertias derived from light curve analyses or from the thermophysical analysis of the mean thermal fluxes confirm the generally small or very small surface thermal inertias of the TNO population, which is consistent with a statistical mean value Γ = 2.5 ± 0.5 MKS.© ESO, 2017., The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 687378. P. Santos-Sanz and J. L. Ortiz would like to acknowledge financial support by the Spanish grant AYA-2014-56637-C2-1-P and the Proyecto de Excelencia de la Junta de Andalucia J.A. 2012-FQM1776. C. Kiss acknowledges financial support from NKFIH grant GINOP-2.3.2-15-2016-00003. E. Vilenius was supported by the German DLR project number 50 OR 1108. R. Duffard acknowledges financial support from the MINECO for his Ramon y Cajal Contract.
Published: 2017

26. Surface evolution of the Anhur region on comet 67P/Churyumov-Gerasimenko from high-resolution OSIRIS images

Author: R. Rodrigo, M. De Cecco, Stefano Debei, P. J. Gutierrez, Ivano Bertini, J. M. Sunshine, P. L. Lamy, Detlef Koschny, S. Fornasier, Xian Shi, Laurent Jorda, G. Cremonese, J. B. Vincent, Marco Fulle, Imre Tóth, Maurizio Pajola, M. L. Lara, J. L. Bertaux, Sabrina Ferrari, C. Güttler, V. Da Deppo, Dennis Bodewits, M. A. Barucci, W-H. Ip, Jakob Deller, Holger Sierks, Clement Feller, Stefano Mottola, Monica Lazzarin, Alice Lucchetti, Cecilia Tubiana, J. J. Lopez Moreno, B. J. R. Davidsson, Horst Uwe Keller, Giampiero Naletto, Francesco Marzari, Pedro Hasselmann, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di Padova, University of Trento [Trento], Dipartimento di Geoscienze [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), California Institute of Technology (CALTECH)-NASA, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA), Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE31-0004,CLASSY,Composition des surfaces du Système Solaire de bas albédo(2017), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, Asteroiden und Kometen, photometry, 010504 meteorology & atmospheric sciences, Comet, observational [methods], Data analysis, Narrow angle, High resolution, Individual, rosetta mission, Equinox, Photometric, imaging spectroscopy, Fault scarp, 01 natural sciences, photometric [techniques], techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, data analysis [methods], Methods, comets, Observational, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], biology, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy, Astronomy and Astrophysics, imaging spectroscopy [techniques], biology.organism_classification, methods: data analysis, Techniques, techniques: imaging spectroscopy, 13. Climate action, Space and Planetary Science, Radiance, Comets, Imaging spectroscopy, methods: observational, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., The southern hemisphere of comet 67P/Churyumov-Gerasimenko (67P) became observable by the Rosetta mission in March 2015, a few months before cometary southern vernal equinox. The Anhur region in the southern part of the comet's larger lobe was found to be highly eroded, enriched in volatiles, and highly active. Aims. We analyze high-resolution images of the Anhur region pre- and post-perihelion acquired by the OSIRIS imaging system on board the Rosetta mission. The Narrow Angle Camera is particularly useful for studying the evolution in Anhur in terms of morphological changes and color variations. Methods. Radiance factor images processed by the OSIRIS pipeline were coregistered, reprojected onto the 3D shape model of the comet, and corrected for the illumination conditions. Results. We find a number of morphological changes in the Anhur region that are related to formation of new scarps; removal of dust coatings; localized resurfacing in some areas, including boulders displacements; and vanishing structures, which implies localized mass loss that we estimate to be higher than 50 million kg. The strongest changes took place in and nearby the Anhur canyon-like structure, where significant dust cover was removed, an entire structure vanished, and many boulders were rearranged. All such changes are potentially associated with one of the most intense outbursts registered by Rosetta during its observations, which occurred one day before perihelion passage. Moreover, in the niche at the foot of a new observed scarp, we also see evidence of water ice exposure that persisted for at least six months. The abundance of water ice, evaluated from a linear mixing model, is relatively high (>20%). Our results confirm that the Anhur region is volatile-rich and probably is the area on 67P with the most pristine exposures near perihelion.© S. Fornasier et al. 2019, OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Goettingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. SF acknowledges the financial support from the France Agence Nationale de la Recherche (programme Classy, ANR-17-CE31-0004). The authors thank Dr. E. Howell for her comments and suggestions which helped us to improve this article.
Published: 2019

27. The dust environment of comet 67P/Churyumov-Gerasimenko from Rosetta OSIRIS/GIADA and VLT observations in the 4.5 to 2.9 AU heliocentric distance range inbound

Author: M. F. A'Hearn, Sebastien Besse, Horst Uwe Keller, M. De Cecco, Alan Fitzsimmons, Emmanuel Jehin, Stefano Debei, Giampiero Naletto, Olivier Hainaut, R. Rodrigo, Francesco Marzari, Carsten Guettler, Géza Kovács, Dennis Bodewits, Olivier Groussin, J. Agarwal, Wing-Huen Ip, Laurent Jorda, Hans Rickman, Detlef Koschny, G. P. Tozzi, N. Oklay, L. M. Lara, V. Della Corte, Colin Snodgrass, F. Moreno, Nicolas Thomas, Jörg Knollenberg, Maurizio Pajola, P. Gutiérrez Marqués, Stubbe F. Hviid, G. Cremonese, Sara Faggi, J. J. Lopez Moreno, Francesca Ferri, B. J. R. Davidsson, E. Kuehrt, J. L. Bertaux, V. Da Deppo, Stefano Mottola, S. Fornasier, J.-R. Kramm, Holger Sierks, J. B. Vincent, Cecilia Tubiana, Monica Lazzarin, Ivano Bertini, P. L. Lamy, Marco Fulle, Cesare Barbieri, P. J. Gutierrez, Michael Kueppers, C. Opitom, M. A. Barucci, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), European Southern Observatory (ESO), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Gauss Professor Akademie der Wissenschaften zu Göttingen, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science, National Central University, Operations Department (ESAC), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), INAF - Osservatorio Astrofisico di Arcetri (OAA), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, ITA, USA, GBR, FRA, DEU, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], Consiglio Nazionale delle Ricerche [Roma] (CNR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Monte Carlo method, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Coma (optics), Astrophysics, 01 natural sciences, Photometry, Methods: data analysis, 0103 physical sciences, Range (statistics), Comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Physics, comets: individual: 67P/Churyumov-Gerasimenko / methods: data analysis / techniques: photometric, Very Large Telescope, Spacecraft, biology, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Mass ratio, biology.organism_classification, 13. Climate action, Space and Planetary Science, astro-ph.EP, Techniques: photometric, Osiris, business, Astrophysics - Earth and Planetary Astrophysics
Abstract: The ESA Rosetta spacecraft, currently orbiting around comet 67P, has already provided in situ measurements of the dust grain properties from several instruments, particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution. To constrain the dust grain properties, we take Rosetta OSIRIS and GIADA results into account, and combine OSIRIS data during the approach phase (from late April to early June 2014) with a large data set of ground-based images that were acquired with the ESO Very Large Telescope (VLT) from February to November 2014. A Monte Carlo dust tail code has been applied to retrieve the dust parameters. Key properties of the grains (density, velocity, and size distribution) were obtained from Rosetta observations: these parameters were used as input of the code to considerably reduce the number of free parameters. In this way, the overall dust mass-loss rate and its dependence on the heliocentric distance could be obtained accurately. The dust parameters derived from the inner coma measurements by OSIRIS and GIADA and from distant imaging using VLT data are consistent, except for the power index of the size-distribution function, which is $\alpha$=--3, instead of $\alpha$=--2, for grains smaller than 1 mm. This is possibly linked to the presence of fluffy aggregates in the coma. The onset of cometary activity occurs at approximately 4.3 au, with a dust production rate of 0.5 kg/s, increasing up to 15 kg/s at 2.9 au. This implies a dust-to-gas mass ratio varying between 3.8 and 6.5 for the best-fit model when combined with water-production rates from the MIRO experiment., Comment: Accepted by Astronomy and Astrophysics (January 17th, 2016)
Published: 2016

28. Observations and analysis of a curved jet in the coma of comet 67P/Churyumov-Gerasimenko

Author: Jörg Knollenberg, Monica Lazzarin, M. F. A'Hearn, Michael Küppers, Jong-Shinn Wu, J.-C. Lee, Ivano Bertini, M. A. Barucci, Wing-Huen Ip, Laurent Jorda, L. M. Lara, P. L. Lamy, Horst Uwe Keller, G. Cremonese, Agata Rozek, Cesare Barbieri, Maurizio Pajola, Nicolas Thomas, J. J. Lopez-Moreno, C. C. Su, J.-R. Kramm, S. Debet, M. De Cecco, Cecilia Tubiana, Giampiero Naletto, F. La Forgia, S. Fornasier, Ekkehard Kührt, Stefano Mottola, I. L. Lai, Francesco Marzari, J. Agarwal, Detlef Koschny, Zhong-Yi Lin, Stubbe F. Hviid, C. Güttler, V. Da Deppo, Géza Kovács, Stephen C. Lowry, R. Rodrigo, Hans Rickman, Marco Fulle, P. J. Gutierrez, Olivier Groussin, Dennis Bodewits, Harald Michalik, J. L. Bertaux, B. J. R. Davidsson, Holger Sierks, N. Oklay, J. B. Vincent, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institute of Space Science [Taiwan], Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Department of Atmospheric Sciences [Taoyuan City], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Department of Information Engineering, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), National funding agencies of Germany (DLR), France (CNES), Italy (Agenzia Spaziale Italiana), Spain (Ministerio de Educación, Cultura y Deporte), Sweden (Swedish National Space Board), ESA, Ministry of Science and Technology of Taiwan, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA), Universität Bern [Bern], Ministerio de Educación, Cultura y Deporte (España), Swedish National Space Board, European Space Agency, Agenzia Spaziale Italiana, Centre National D'Etudes Spatiales (France), German Centre for Air and Space Travel, National Science and Technology Development Agency (Thailand), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, Gravity (chemistry), 010504 meteorology & atmospheric sciences, Terminal velocity, 530 Physics, Comet, Equator, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Coma (optics), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, medicine, comets, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Jet (fluid), Astronomy and Astrophysics, Space and Planetary Science, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, 620 Engineering, medicine.anatomical_structure, Drag, Astrophysics::Earth and Planetary Astrophysics, Nucleus, Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims. We analyze the physical properties and dynamical origin of a curved jet of comet 67P/Churyumov-Gerasimenko that was observed repeatedly in several nucleus rotations starting on May 30 and persisting until early August, 2015. Methods. We simulated the motion of dust grains ejected from the nucleus surface under the influence of the gravity and viscous drag effect of the expanding gas flow from the rotating nucleus. Results. The formation of the curved jet is a combination of the size of the dust particles (∼0.1-1 mm) and the location of the source region near the nucleus equator. This enhances the spiral feature of the collimated dust stream after the dust is accelerated to a terminal speed on the order of m s. © ESO, 2016., The support of the national funding agencies of Germany (Deutschen Zentrums fur Luft- und Raumfahrt), France (Centre National d'Etudes Spatiales), Italy (Agenzia Spaziale Italiana), Spain (Ministerio de Educacion, Cultura y Deporte), Sweden (Swedish National Space Board; grant no. 74/10:2), and the ESA Technical Directorate is gratefully acknowledged. This work was also supported by grant number NSC 102-2112-M-008-013-MY3 and MOST 104-2119-M-008-024 from the Ministry of Science and Technology of Taiwan. We are indebted to the whole Rosetta mission team, Science Ground Segment, and Rosetta Mission Operation Control for their hard work making this mission possible.
Published: 2016

29. CHANGES in the PHYSICAL ENVIRONMENT of the INNER COMA of 67P/CHURYUMOV-GERASIMENKO with DECREASING HELIOCENTRIC DISTANCE

Author: Imre Tóth, E. Kuehrt, P. J. Gutierrez, Ivano Bertini, Detlef Koschny, F. La Forgia, J.-R. Kramm, Steve Boudreault, S. Fornasier, Nicolas Thomas, J. J. Lopez-Moreno, Giampiero Naletto, Cecilia Tubiana, Francesco Marzari, Hans Rickman, Carsten Guettler, Olivier Groussin, M. A. Barucci, L. M. Lara, Monica Lazzarin, R. Rodrigo, Michael F. A'Hearn, Cesare Barbieri, A. Giquel, Michael Kueppers, Jörg Knollenberg, Colin Snodgrass, Zhong-Yi Lin, Marco Fulle, Stefano Debei, N. Oklay, Stubbe F. Hviid, P. Lamy, B. J. R. Davidsson, Géza Kovács, V. DaDeppo, J. L. Bertaux, H. U. Keller, Holger Sierks, Wing-Huen Ip, Laurent Jorda, Dennis Bodewits, G. Cremonese, M. De Cecco, Xian Shi, J. B. Vincent, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Gauss Professor Akademie der Wissenschaften zu Göttingen, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universita degli Studi di Padova-Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], ITA, USA, GBR, FRA, DEU, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: 010504 meteorology & atmospheric sciences, atomic processes, comets: individual (67P/Churyumov-Gerasimenko), molecular processes, plasmas, radiation mechanisms: non-thermal, techniques: image processing, 530 Physics, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Coma (optics), Electron, Astrophysics, Spatial distribution, 01 natural sciences, comets: individual: 67P/Churyumov--Gerasimenko, 0103 physical sciences, Emission spectrum, comets, 10. No inequality, 010303 astronomy & astrophysics, Electron ionization, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Plume, Space and Planetary Science, 13. Climate action, Excitation, Astrophysics - Earth and Planetary Astrophysics
Abstract: The Wide Angle Camera of the OSIRIS instrument on board the Rosetta spacecraft is equipped with several narrowband filters that are centered on the emission lines and bands of various fragment species. These are used to determine the evolution of the production and spatial distribution of the gas in the inner coma of comet 67P with time and heliocentric distance, here between 2.6 - 1.3 AU pre-perihelion. Our observations indicate that the emission observed in the OH, OI, CN, NH, and NH2 filters is mostly produced by dissociative electron impact excitation of different parent species. We conclude that CO2 rather than H2O is a significant source of the [OI] 630 nm emission. A strong plume-like feature observed in the in CN and [OI] filters is present throughout our observations. This plume is not present in OH emission and indicates a local enhancement of the CO2/H2O ratio by as much as a factor of 3. We observed a sudden decrease in intensity levels after March 2015, which we attribute to decreased electron temperatures in the first kilometers above the nucleus surface., 6 figures, 6 tables
Published: 2016

30. Are fractured cliffs the source of cometary dust jets? Insights from OSIRIS/Rosetta at 67P/Churyumov-Gerasimenko

Author: Frank Scholten, M. De Cecco, Imre Tóth, H. U. Keller, M. F. A'Hearn, M. A. Barucci, Ivano Bertini, Detlef Koschny, Nicolas Thomas, Michael Küppers, R. Rodrigo, Xian Shi, J. L. Bertaux, Stephen C. Lowry, J. B. Vincent, P. L. Lamy, Stefano Mottola, C. Güttler, X. Hu, L. M. Lara, V. Da Deppo, Holger Sierks, Marco Fulle, S. Fornasier, Wing-Huen Ip, Maurizio Pajola, Laurent Jorda, Géza Kovács, Matteo Massironi, Mohamed Ramy El-Maarry, Dennis Bodewits, F. Moreno, G. Cremonese, P. J. Gutierrez, Stubbe F. Hviid, Hans Rickman, Marc Hofmann, Francesco Marzari, Ekkehard Kührt, Giampiero Naletto, Stefano Debei, Cesare Barbieri, Zhong-Yi Lin, Olivier Groussin, Jörg Knollenberg, F. Preusker, P. Gutiérrez-Marquez, J.-R. Kramm, Sebastien Besse, Cecilia Tubiana, J. J. Lopez Moreno, B. J. R. Davidsson, S. Höfner, N. Oklay, Monica Lazzarin, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Gauss Professor Akademie der Wissenschaften zu Göttingen, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Mechatronics, Optics and Mechanical Engineering Informatics (MOMEI), Budapest University of Technology and Economics [Budapest] (BME), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Department of Information Engineering [Padova] (DEI), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), European Space Agency, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Swedish National Space Agency, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], High resolution, comets: general / comets: individual: 67P/Churyumov-Gerasimenko, 01 natural sciences, Observational evidence, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Northern Hemisphere, Astronomy, general [Comets], biology.organism_classification, 13. Climate action, Osiris, Geology
Abstract: Context. Dust jets (i.e., fuzzy collimated streams of cometary material arising from the nucleus) have been observed in situ on all comets since the Giotto mission flew by comet 1P/Halley in 1986, and yet their formation mechanism remains unknown. Several solutions have been proposed involving either specific properties of the active areas or the local topography to create and focus the gas and dust flows. While the nucleus morphology seems to be responsible for the larger features, high resolution imagery has shown that broad streams are composed of many smaller jets (a few meters wide) that connect directly to the nucleus surface. Aims. We monitored these jets at high resolution and over several months to understand what the physical processes are that drive their formation and how this affects the surface. Methods. Using many images of the same areas with different viewing angles, we performed a 3-dimensional reconstruction of collimated jets and linked them precisely to their sources on the nucleus. Results. We show here observational evidence that the northern hemisphere jets of comet 67P/Churyumov-Gerasimenko arise from areas with sharp topographic changes and describe the physical processes involved. We propose a model in which active cliffs are the main source of jet-like features and therefore of the regions eroding the fastest on comets. We suggest that this is a common mechanism taking place on all comets., Astronomy and Astrophysics 587 (2016)##EDP Sciences##The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MINECO), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2016
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31. A mini outburst from the nightside of comet 67P/Churyumov-Gerasimenko observed by the OSIRIS camera on Rosetta

Author: Frank Preusker, Hans Rickman, J. J. Lopez Moreno, Holger Sierks, Carsten Güttler, Michael Küppers, Cesare Barbieri, J.-R. Kramm, Giampiero Naletto, M. A. Barucci, W-H. Ip, Nilda Oklay, J. B. Vincent, Stefano Mottola, V. Da Deppo, Ivano Bertini, P. L. Lamy, Zhong-Yi Lin, Francesco Marzari, Michael F. A'Hearn, Stefano Debei, Detlef Koschny, Nicolas Thomas, B. J. R. Davidsson, Cecilia Tubiana, Monica Lazzarin, Stubbe F. Hviid, J. L. Bertaux, P. J. Gutiérrez, Dennis Bodewits, S. Fornasier, Frank Scholten, Ekkehard Kührt, L. M. Lara, Maurizio Pajola, Olivier Groussin, Marco Fulle, Horst Uwe Keller, Jörg Knollenberg, Rafael Rodrigo, M. De Cecco, Laurent Jorda, G. Cremonese, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], Università degli Studi di Trento (UNITN), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Ministerio de Educación y Ciencia (España), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA)-European Space Agency (ESA), and Universität Bern [Bern]
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet dust, Astrophysics::High Energy Astrophysical Phenomena, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Power law, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: numerical, Astronomy and Astrophysics, Space and Planetary Science, comets: general / comets: individual: 67P/Churyumov-Gerasimenko / methods: numerical, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Range (particle radiation), Jet (fluid), numerical [Methods], Planetengeodäsie, Astronomy, general [Comets], 13. Climate action, Particle-size distribution, Radiance, Astrophysics::Earth and Planetary Astrophysics, Event (particle physics)
Abstract: Context. On 12 March 2015 the OSIRIS WAC camera onboard the ESA Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko observed a small outburst originating from the Imhotep region at the foot of the big lobe of the comet. These measurements are unique since it was the first time that the initial phase of a transient outburst event could be directly observed. Aims. We investigate the evolution of the dust jet in order to derive clues about the outburst source mechanism and the ejected dust particles, in particular the dust mass, dust-to-gas ratio and the particle size distribution. Methods. Analysis of the images and of the observation geometry using comet shape models in combination with gasdynamic modeling of the transient dust jet were the main tools used in this study. Synthetic images were computed for comparison with the observations. Results. Analysis of the geometry revealed that the source region was not illuminated until 1.5 h after the event implying true nightside activity was observed. The outburst lasted for less than one hour and the average dust production rate during the initial four minutes was of the order of 1 kg/s. During this time the outburst dust production rate was approximately constant, no sign for an initial explosion could be detected. For dust grains between 0.01-1 mm a power law size distribution characterized by an index of about 2.6 provides the best fit to the observed radiance profiles. The dust-to-gas ratio of the outburst jet is in the range 0.6-1.8. © 2016 ESO., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB; Grant No. 74/10:2), and the ESA Technical Directorate is gratefully acknowledged. H. Rickman was also supported by Grant No. 2011/01/B/ST9/05442 of the Polish National Science Center.
Published: 2016
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32. Search for Steins’ surface inhomogeneities from OSIRIS Rosetta images

Author: Stubbe F. Hviid, Sara Magrin, Cesare Barbieri, S. Fornasier, Simone Marchi, Holger Sierks, M. Fulchignoni, Antonella Barucci, Monica Lazzarin, Laurent Jorda, U. Keller, C. Leyrat, Irina Belskaya, Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Surface (mathematics), 010504 meteorology & atmospheric sciences, Astrophysics, Osiris, 01 natural sciences, Latitude, Polyhedron, Optics, 0103 physical sciences, Rosetta mission, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], biology, business.industry, Astronomy and Astrophysics, biology.organism_classification, asteroid surface composition, Wavelength, Space and Planetary Science, Asteroid, Content (measure theory), Longitude, business
Abstract: International audience; We investigate the possible presence of heterogeneous surface features on asteroid (2867) Steins, using the G-mode multivariate statistical method (Coradini et al., 1977) applied to Rosetta/OSIRIS images. We analyze both NAC and WAC images obtained near around the closest approach that occurred on September 5th, 2008, through different filters centered on wavelengths ranging from 295 to 986 nm. The shape of Steins is modeled as a polyhedron of almost 58 000 facets. Photometric corrections were performed using Hapke's (2002) model to compensate for the variable illuminations conditions at the surface. The G-mode classification method was performed on all visible and illuminated facets, i.e. in a region limited to [-50 degrees,+60 degrees] in latitude and [-40 degrees,+90 degrees] in longitude, that represents almost 30% of the total surface. The analyzed set of facets does not show any significant difference in the reflected light content, suggesting no surface inhomogeneities larger than 4% at the 95% confidence level. (C) 2010 Elsevier Ltd. All rights reserved.
Published: 2010

33. Iqueye, a single photon-counting photometer applied to the ESO new technology telescope

Author: P. Zoccarato, Filippo Messina, Giampiero Naletto, Pietro Bolli, Claudio Pernechele, Fabrizio Tamburini, Simone Marchi, Ivan Capraro, Sergio Billotta, Cesare Barbieri, Enrico Verroi, C. Germanà, Da Deppo, Giovanni Bonanno, G. Anzolin, Massimiliano Belluso, A. Di Paola, C. Facchinetti, S. Fornasier, T. Occhipinti, Enrico Giro, Mirco Zaccariotto, Luca Zampieri, Università degli Studi di Padova = University of Padua (Unipd), INAF-Osservatorio Astronomico di Roma (INAF-OAR), Italian Space Agency, Institute of Photonic, Universitat Politecnica de Catalunya (ICFO), INAF-Osservatorio Astrofisico di Catania (INAF-OACt), INAF-Osservatorio Astronomico di Cagliari, CNR-INFM Luxor, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and INAF-Osservatorio Astronomico di Padova
Subjects: Physics, Aperture, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Context (language use), Photometer, New Technology Telescope, Photon counting, law.invention, Telescope, Optical pulsar, Optics, Single-photon avalanche diode, Space and Planetary Science, law, Astrophysics::Earth and Planetary Astrophysics, photometers, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Remote sensing
Abstract: International audience; Context: A new extremely high speed photon-counting photometer, Iqueye, has been installed and tested at the New Technology Telescope, in La Silla. Aims: This instrument is the second prototype of a ``quantum'' photometer being developed for future Extremely Large Telescopes of 30-50 m aperture. Methods: Iqueye divides the telescope aperture into four portions, each feeding a single photon avalanche diode. The counts from the four channels are collected by a time-to-digital converter board, where each photon is appropriately time-tagged. Owing to a rubidium oscillator and a GPS receiver, an absolute rms timing accuracy better than 0.5 ns during one-hour observations is achieved. The system can sustain a count rate of up to 8 MHz uninterruptedly for an entire night of observation. Results: During five nights of observations, the system performed smoothly, and the observations of optical pulsar calibration targets provided excellent results.
Published: 2009

34. Visible spectroscopy of the new ESO large programme on trans-Neptunian objects and Centaurs: final results

Author: Francesca E. DeMeo, F. Merlin, C. de Bergh, D. Perna, M. A. Barucci, A. Guilbert, A. Delsanti, E. Dotto, Alain Doressoundiram, A. Alvarez-Candal, S. Fornasier, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory, Department of Astronomy, University of Maryland, and INAF-Osservatorio Astronomico di Roma (INAF-OAR)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Orbital elements, Physics, education.field_of_study, Population, FOS: Physical sciences, Astronomy and Astrophysics, Orbital eccentricity, Astrophysics, Spectral line, Orbital inclination, Space and Planetary Science, Absorption band, Spectral slope, Astrophysics::Earth and Planetary Astrophysics, Trans-Neptunian object, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], education, Astrophysics - Earth and Planetary Astrophysics
Abstract: A second large programme (LP) for the physical studies of TNOs and Centaurs, started at ESO Cerro Paranal on October 2006 to obtain high-quality data, has recently been concluded. In this paper we present the spectra of these pristine bodies obtained in the visible range during the last two semesters of the LP. We investigate the spectral behaviour of the TNOs and Centaurs observed, and we analyse the spectral slopes distribution of the full data set coming from this LP and from the literature. We computed the spectral slope for each observed object, and searched for possible weak absorption features. A statistical analysis was performed on a total sample of 73 TNOs and Centaurs to look for possible correlations between dynamical classes, orbital parameters, and spectral gradient. We obtained new spectra for 28 bodies, 15 of which were observed for the first time. All the new presented spectra are featureless, including 2003 AZ84, for which a faint and broad absorption band possibly attributed to hydrated silicates on its surface has been reported. The data confirm a wide variety of spectral behaviours, with neutral--grey to very red gradients. An analysis of the spectral slopes available from this LP and in the literature for a total sample of 73 Centaurs and TNOs shows that there is a lack of very red objects in the classical population. We present the results of the statistical analysis of the spectral slope distribution versus orbital parameters. In particular, we confirm a strong anticorrelation between spectral slope and orbital inclination for the classical population. A strong correlation is also found between the spectral slope and orbital eccentricity for resonant TNOs, with objects having higher spectral slope values with increasing eccentricity., 11 pages, 9 figures
Published: 2009

35. ESO large program about transneptunian objects: surface variations on (47171) 1999 TC36

Author: F. Merlin, G. P. Tozzi, S. Fornasier, A. Delsanti, M. A. Barucci, Silvia Protopapa, A. Alvarez-Candal, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA)
Subjects: Physics, Scattering, Astronomy and Astrophysics, Tholin, Astrophysics, Reflectivity, Spectral line, symbols.namesake, Atmospheric radiative transfer codes, Space and Planetary Science, Radiative transfer, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Visible spectrum
Abstract: International audience; Aims: We investigate the surface composition of the Plutino (47171) 1999 TC{36}. Methods: We completed near-infrared photometric and spectroscopic observations of (47171) 1999 TC{36} with the adaptive optics instrument NACO at the ESO VLT during 12 October 2006, and present these data with ISAAC and SINFONI spectroscopic observations carried out about one month later on 9 November 2006 and 8 November 2006, respectively. The ISAAC and SINFONI spectroscopic observations were combined with a visible spectrum obtained by FORS1 on 9 November 2006. Composition and properties of the compounds present on the surface of the target are investigated by applying a Hapke radiative transfer model to the measured spectra and to previously published observations. Results: We present the relative reflectance spectrum of (47171) 1999 TC{36} in the wavelength range (0.37-2.33) mum. An intimate mixture of Triton tholin, Titan tholin, serpentine, and Triton tholin diluted in water ice represents the best-fit model description of the measured spectrum. Any significant differences from the published spectra of (47171) 1999 TC{36} taken on 2001 and 2003 could be due to surface heterogeneity.
Published: 2009

36. AquEYE, a single photon counting photometer for astronomy

Author: Enrico Giro, Fernando Pedichini, Fabrizio Tamburini, A. Di Paola, Luca Zampieri, Cesare Barbieri, Enrico Verroi, Pietro Bolli, Mirco Zaccariotto, Claudio Pernechele, V. Da Deppo, P. Zoccarato, Filippo Messina, T. Occhipinti, Simone Marchi, Giovanni Bonanno, Sergio Billotta, Mauro D'Onofrio, C. Facchinetti, Ivan Capraro, Giampiero Naletto, G. Anzolin, Massimiliano Belluso, and S. Fornasier
Subjects: Physics, Photon, Physics::Instrumentation and Detectors, business.industry, Aperture, Detector, Photometer, Avalanche photodiode, Atomic and Molecular Physics, and Optics, Photon counting, law.invention, Telescope, Optics, Rubidium standard, law, Optoelectronics, business
Abstract: This paper describes the results obtained so far with AquEYE, a single photon counting, fixed aperture photometer for the Asiago 182 cm telescope. AquEYE has been conceived as a prototype of a truly 'quantum' photometer for future Extremely Large Telescopes of 30-50 m aperture. This prototype is characterized by four independent channels equipped with single photon avalanche diodes (SPADs) as detectors. The counts from the four channels are acquired by a TDC board which has a nominal 25 ps time tagging capability. Taking into account the 35 ps jitter in the SPAD itself, the overall precision of the time tags is of the order of 50 ps. The internal oscillator is locked to an external rubidium clock; a GPS pulse per second is collected by the TDC itself to obtain a UTC reference. The maximum photon count rate which the present system can sustain is 12 MHz.
Published: 2009

37. Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta

Author: F, Capaccioni, A, Coradini, G, Filacchione, S, Erard, G, Arnold, P, Drossart, M C, De Sanctis, D, Bockelee-Morvan, M T, Capria, F, Tosi, C, Leyrat, B, Schmitt, E, Quirico, P, Cerroni, V, Mennella, A, Raponi, M, Ciarniello, T, McCord, L, Moroz, E, Palomba, E, Ammannito, M A, Barucci, G, Bellucci, J, Benkhoff, J P, Bibring, A, Blanco, M, Blecka, R, Carlson, U, Carsenty, L, Colangeli, M, Combes, M, Combi, J, Crovisier, T, Encrenaz, C, Federico, U, Fink, S, Fonti, W H, Ip, P, Irwin, R, Jaumann, E, Kuehrt, Y, Langevin, G, Magni, S, Mottola, V, Orofino, P, Palumbo, G, Piccioni, U, Schade, F, Taylor, D, Tiphene, G P, Tozzi, P, Beck, N, Biver, L, Bonal, J-Ph, Combe, D, Despan, E, Flamini, S, Fornasier, A, Frigeri, D, Grassi, M, Gudipati, A, Longobardo, K, Markus, F, Merlin, R, Orosei, G, Rinaldi, K, Stephan, M, Cartacci, A, Cicchetti, S, Giuppi, Y, Hello, F, Henry, S, Jacquinod, R, Noschese, G, Peter, R, Politi, J M, Reess, and A, Semery
Abstract: The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.
Published: 2015

38. Comet 67P/Churyumov-Gerasimenko: Constraints on its origin from OSIRIS observations

Author: H. Rickman, S. Marchi, M. F. A’Hearn, C. Barbieri, M. R. El-Maarry, C. Güttler, W.-H. Ip, H. U. Keller, P. Lamy, F. Marzari, M. Massironi, G. Naletto, M. Pajola, H. Sierks, D. Koschny, R. Rodrigo, M. A. Barucci, J.-L. Bertaux, I. Bertini, G. Cremonese, V. Da Deppo, S. Debei, M. De Cecco, S. Fornasier, M. Fulle, O. Groussin, P. J. Gutiérrez, S. F. Hviid, L. Jorda, J. Knollenberg, J.-R. Kramm, E. Kührt, M. Küppers, L. M. Lara, M. Lazzarin, J. J. Lopez Moreno, H. Michalik, L. Sabau, N. Thomas, J.-B. Vincent, K.-P. Wenzel, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Geoscienze [Padova], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Industrial Engineering [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Università degli Studi di Trento (UNITN), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Institut für Datentechnik und Kommunikationsnetze, Instituto Nacional de Técnica Aeroespacial (INTA), ITA, USA, GBR, FRA, DEU, ESP, Università degli Studi di Padova = University of Padua (Unipd), Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: 67P/Churyumov-Gerasimenko, Solar System, Planetesimal, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Contact binary, Astrophysics, Parent body, medicine, collisional evolution, comets, planetesimals, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, Accretion (astrophysics), medicine.anatomical_structure, Comet 67P/Churyumov-Gerasimenko, 13. Climate action, Formation and evolution of the Solar System, Nucleus, Astrophysics - Earth and Planetary Astrophysics
Abstract: One of the main aims of the ESA Rosetta mission is to study the origin of the solar system by exploring comet 67P/Churyumov-Gerasimenko at close range. In this paper we discuss the origin and evolution of comet 67P/Churyumov-Gerasimenko in relation to that of comets in general and in the framework of current solar system formation models. We use data from the OSIRIS scientific cameras as basic constraints. In particular, we discuss the overall bi-lobate shape and the presence of key geological features, such as layers and fractures. We also treat the problem of collisional evolution of comet nuclei by a particle-in-a-box calculation for an estimate of the probability of survival for 67P/Churyumov-Gerasimenko during the early epochs of the solar system. We argue that the two lobes of the 67P/Churyumov-Gerasimenko nucleus are derived from two distinct objects that have formed a contact binary via a gentle merger. The lobes are separate bodies, though sufficiently similar to have formed in the same environment. An estimate of the collisional rate in the primordial, trans-planetary disk shows that most comets of similar size to 67P/Churyumov-Gerasimenko are likely collisional fragments, although survival of primordial planetesimals cannot be excluded. A collisional origin of the contact binary is suggested, and the low bulk density of the aggregate and abundance of volatile species show that a very gentle merger must have occurred. We thus consider two main scenarios: the primordial accretion of planetesimals, and the re-accretion of fragments after an energetic impact onto a larger parent body. We point to the primordial signatures exhibited by 67P/Churyumov-Gerasimenko and other comet nuclei as critical tests of the collisional evolution., Comment: Accepted, to appear on Astronomy & Astrophysics
Published: 2015

39. Is Sedna another Triton?

Author: Dale P. Cruikshank, François Poulet, C. M. Dalle Ore, M. A. Barucci, Elisabetta Dotto, C. de Bergh, F. Merlin, S. Fornasier, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), SETI Institute, NASA Ames Research Center, Moffett Field, INAF-Osservatorio Astronomico di Roma (INAF-OAR), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Search for Extraterrestrial Intelligence Institute (SETI), and Università degli Studi di Padova = University of Padua (Unipd)
Subjects: Physics, Photometry (optics), Very Large Telescope, Space and Planetary Science, Infrared, Observatory, Astronomy, Astronomy and Astrophysics, Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy
Abstract: International audience; 90377 Sedna is, so far, the largest and most distant trans-neptunian object. It was observed at visible and near-infrared wavelengths using simultaneously two 8.2 m telescopes at the Very Large Telescope of the European Southern Observatory. The spectrum of Sedna suggests the presence on its surface of different ices (total abundance >50%). Its surface composition is different from that determined for other trans-neptunian objects, and apparently resembles that of Triton, particularly in terms of the possible presence of nitrogen and methane ices.
Published: 2005

40. Low delta-V near-Earth asteroids: A survey of suitable targets for space missions

Author: S. Ieva (1, 2, E. Dotto (1), D. Perna (2), M. A. Barucci (2), F. Bernardi (4), S. Fornasier (2, F. De Luise (6), E. Perozzi (7, 8, A. Rossi (10), J. R. Brucato (11), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), and INAF - Osservatorio Astrofisico di Arcetri (OAA)
Subjects: asteroids, spectroscopy, Solar System, 010504 meteorology & atmospheric sciences, astrobiology, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Astrobiology, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Ordinary chondrite, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Near-Earth object, Astronomy and Astrophysics, Delta-v (physics), Space and Planetary Science, Asteroid, Extraterrestrial life, minor planets, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: In the last decades Near-Earth Objects (NEOs) have become very important targets to study, since they can give us clues to the formation, evolution and composition of the Solar System. In addition, they may represent either a threat to humankind, or a repository of extraterrestrial resources for suitable space-borne missions. Within this framework, the choice of next-generation mission targets and the characterisation of a potential threat to our planet deserve special attention. To date, only a small part of the 11,000 discovered NEOs have been physically characterised. From ground and space-based observations one can determine some basic physical properties of these objects using visible and infrared spectroscopy. We present data for 13 objects observed with different telescopes around the world (NASA-IRTF, ESO-NTT, TNG) in the 0.4 - 2.5 um spectral range, within the NEOSURFACE survey (http://www.oa-roma.inaf.it/planet/NEOSurface.html). Objects are chosen from among the more accessible for a rendez-vous mission. All of them are characterised by a delta-V (the change in velocity needed for transferring a spacecraft from low-Earth orbit to rendez-vous with NEOs) lower than 10.5 km/s, well below the Solar System escape velocity (12.3 km/s). We taxonomically classify 9 of these objects for the first time. 11 objects belong to the S-complex taxonomy; the other 2 belong to the C-complex. We constrain the surface composition of these objects by comparing their spectra with meteorites from the RELAB database. We also compute olivine and pyroxene mineralogy for asteroids with a clear evidence of pyroxene bands. Mineralogy confirms the similarity with the already found H, L or LL ordinary chondrite analogues., 9 pages, 7 figures, to be published in A&A Minor changes by language editor
Published: 2014

41. 'TNOs are Cool': A survey of the trans-Neptunian region. XI. A Herschel-PACS view of 16 Centaurs

Author: T. G. Mueller, Cs. Kiss, Esa Vilenius, Nuno Peixinho, E. Lellouch, Noemi Pinilla-Alonso, Michael Mueller, J. L. Ortiz, A. Delsanti, J. A. Stansberry, A. Pal, David Trilling, Pablo Santos-Sanz, S. Fornasier, Rene Duffard, Michael Mommert, Instituto de Astrofisica de Andalucia, CSIC (IAA), Max-Planck-Institut fur extraterrestrische Physik, Postfach 1312, Giessenbachstr., 85741, Garching, Germany, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Konkoly Thege 15-17, 1121, Budapest, Hungary, SRON Netherlands Institute for Space Research, Space Telescope Science Institute (STScI), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Unidad de Astronomia, Facultad de Ciencias Basicas, Universidad de Antofagasta, and Department of Physics and Astronomy, Northern Arizona University, Flagstaff
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Mean diameter, Physics, Orbital elements, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Centaur, Photometry (optics), 13. Climate action, Space and Planetary Science, astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, Monochromatic color, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, Data reduction
Abstract: Centaurs are the transitional population between trans-Neptunian objects (TNOs) and Jupiter-family comets. For this reason it is possible to access the smaller ones, which is more difficult to do with the TNO population. The goal of this work is to characterize a set of 16 Centaurs in terms of their size, albedo, and thermal properties. We study the correlations, for a more extended sample obtained from the literature, of diameter, albedo, orbital parameters, and spectral slopes. We performed three-band photometric observations using Herschel-PACS and used a consistent method for the data reduction and aperture photometry of this sample to obtain monochromatic flux densities at 70, 100, and 160 $��$m. Additionally, we used Spitzer-MIPS flux densities at 24 and 70 $��$m when available. We also included in our Centaur sample scattered disk objects (SDOs), a dynamical family of TNOS, using results previously published by our team, and some Centaurs observed only with the Spitzer/MIPS instrument. We have determined new radiometric sizes and albedos of 16 Centaurs. The first conclusion is that the albedos of Centaur objects are not correlated with their orbital parameters. Similarly, there is no correlation between diameter and orbital parameters. Most of the objects in our sample are dark (pv < 7%) and most of them are small (D < 120km). However, there is no correlation between albedo and diameter, in particular for the group of the small objects as albedo values are homogeneously distributed between 4 to 16%. The correlation with the color of the objects showed that red objects are all small (mean diameter 65 km), while the gray ones span a wide range of sizes (mean diameter 120 km). Moreover, the gray objects tend to be darker, with a mean albedo of 5.6%, compared with a mean of 8.5% (ranging from 5 to 15%) for the red objects., 16 pages, 7 figures. accepted at A&A. in press
Published: 2014

42. Spectroscopic comparison of aqueous altered asteroids with CM2 carbonaceous chondrite meteorites

Author: Monica Lazzarin, M. A. Barucci, Cesare Barbieri, and S. Fornasier
Subjects: Aqueous altered asteroids, Carbonaceous Chondrite meteorites, spectroscopy, Physics, Solar System, Aqueous solution, Meteoroid, General Physics and Astronomy, Astronomy, Astrophysics, Astrobiology, Meteorite, Chondrite, Asteroid, Carbonaceous chondrite, Spectroscopy
Abstract: In the last year we have started a spectroscopic investigation of asteroids located in the region of the main- belt between about 2.2 and 3.6 AU. The aim of this work is to study the aqueous alteration process which acted in that zone, dominated by low albedo C{type asteroids, and to compare the spectra of these hydrous objects with those of CM2 carbonaceous chondrite meteorites. In fact, the spectra of these meteorites reveal features probably due to aqueous altered materials on their surfaces. The study of the aqueous alteration process can give important information on the chemical and thermal evo- lution of the earliest Solar System. More that 65% of the investigated objects have re- vealed features suggesting the presence of hydrous mate- rials. The comparison of the spectra of the hydrated aster- oids obtained to date with those of several CM2 carbona- ceous chondrite meteorites seems to indicate that aqueous altered asteroids could be the parents of CM2 meteorites. The data have been obtained during several observa- tional runs at the Asiago Observatory with the 1.8 m tele- scope and at ESO{LaSilla with the 1.5 m telescope.
Published: 1999

43. Detection of exposed H2O ice on the nucleus of comet 67P/Churyumov-Gerasimenko

Author: Ivano Bertini, Ekkehard Kührt, Michael Küppers, Cesare Barbieri, Monica Lazzarin, P. L. Lamy, S. Fornasier, Gianrico Filacchione, Bernard Schmitt, Antoine Pommerol, Laurent Jorda, J. D. P. Deshapriya, Matteo Massironi, Gabriele Arnold, Holger Sierks, Dominique Bockelée-Morvan, Stubbe F. Hviid, C. Güttler, S. Fonti, F. Merlin, C. Leyrat, Cecilia Tubiana, J. B. Vincent, V. Da Deppo, A. Guilbert-Lepoutre, J.-R. Kramm, Marco Fulle, Mauro Ciarniello, Mohamed Ramy El-Maarry, Olivier Groussin, Detlef Koschny, Hans Rickman, F. Mancarella, L. M. Lara, Nicolas Thomas, M. T. Capria, N. Oklay, M. A. Barucci, W-H. Ip, Stéphane Erard, Maurizio Pajola, Priscilla Cerroni, G. Cremonese, Clement Feller, D. Perna, Andrea Raponi, Eric Quirico, J. J. Lopez Moreno, C. de Sanctis, Stefano Mottola, P. Drossart, B. J. R. Davidsson, Batiste Rousseau, Ernesto Palomba, R. Rodrigo, M. F. A'Hearn, J. L. Bertaux, Horst Uwe Keller, Pedro Hasselmann, Jörg Knollenberg, Marcello Fulchignoni, David Kappel, Fabrizio Capaccioni, Federico Tosi, Giampiero Naletto, Francesco Marzari, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Department of Information Engineering [Padova] (DEI), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Physics [Lecce], Università del Salento [Lecce], INAF - Osservatorio Astronomico di Trieste (OAT), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), NASA Ames Research Center (ARC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Ministerio de Economía y Competitividad (España), European Space Agency, Swedish National Space Agency, Agenzia Spaziale Italiana, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Sonnensystemforschung (MPS), Universität Bern [Bern], Universita degli Studi di Padova, European Space Agency (ESA), Polska Akademia Nauk (PAN), Technische Universität Braunschweig [Braunschweig], IMPEC - LATMOS, European Space Agency (ESA)-European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH)-NASA, Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), ITA, USA, FRA, DEU, ESP, TWN, NLD, POL, SWE, and CHE
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Context (language use), 01 natural sciences, Spectral line, Photometry, individual: 67P/Churyumov-Gerasimenko [Comets], Methods: data analysis, 0103 physical sciences, Comets, medicine, image processing [Techniques], data analysis [Methods], Techniques: imaging spectroscopy, 010303 astronomy & astrophysics, Spectroscopy, 0105 earth and related environmental sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Physics, biology, Pixel, Spots, Techniques: photometric, imaging spectroscopy [Techniques], photometric [Techniques], Astronomy, Astronomy and Astrophysics, comets: individual: 67P/Churyumov-Gerasimenko – techniques: imaging spectroscopy – techniques: photometric – techniques: image processing – methods: data analysis, biology.organism_classification, comets: individual: 67P/Churyumov-Gerasimenko / techniques: imaging spectroscopy / techniques: photometric / techniques: image processing / methods: data analysis, medicine.anatomical_structure, Space and Planetary Science, Absorption band, Osiris, Nucleus
Abstract: [Context] Since the orbital insertion of the Rosetta spacecraft, comet 67P/Churyumov-Gerasimenko (67P) has been mapped by OSIRIS camera and VIRTIS spectro-imager, producing a huge quantity of images and spectra of the comet's nucleus., [Aims] The aim of this work is to search for the presence of HO on the nucleus which, in general, appears very dark and rich in dehydrated organic material. After selecting images of the bright spots which could be good candidates to search for HO ice, taken at high resolution by OSIRIS, we check for spectral cubes of the selected coordinates to identify these spots observed by VIRTIS., [Methods] The selected OSIRIS images were processed with the OSIRIS standard pipeline and corrected for the illumination conditions for each pixel using the Lommel-Seeliger disk law. The spots with higher I/F were selected and then analysed spectrophotometrically and compared with the surrounding area. We selected 13 spots as good targets to be analysed by VIRTIS to search for the 2 μm absorption band of water ice in the VIRTIS spectral cubes., [Results] Out of the 13 selected bright spots, eight of them present positive HO ice detection on the VIRTIS data. A spectral analysis was performed and the approximate temperature of each spot was computed. The HO ice content was confirmed by modeling the spectra with mixing (areal and intimate) of HO ice and dark terrain, using Hapke's radiative transfer modeling. We also present a detailed analysis of the detected spots., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2016

44. Polarimetry of trans-Neptunian objects (136472) Makemake and (90482) Orcus

Author: Karri Muinonen, M. A. Barucci, S. Fornasier, Yu. G. Shkuratov, Stefano Bagnulo, G. P. Tozzi, Irina Belskaya, A. Stinson, Institute of Astronomy [Kharkiv], V.N. Karazin Kharkiv National University (KhNU), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Armagh Observatory [Armagh], INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), and Finnish Geodetic Institute (FGI)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, biology, Thin layer, Dwarf planet, Polarimetry, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, biology.organism_classification, 01 natural sciences, Pluto, Space and Planetary Science, 0103 physical sciences, Surface structure, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Eris, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: Context. We study the surface properties of transneptunian populations of Solar-system bodies. Aims. We investigate the surface characteristics of the dwarf planet (136472) Makemake and the resonant object (90482) Orcus. Methods. Using the FORS2 instrument of the ESO-VLT we have carried out linear polarisation measurements of Makemake and Orcus. Results. Polarisation of Orcus is similar to that of smaller size objects. The polarimetric properties of Makemake are very close to those of Eris and Pluto. We have not found any significant differences in the polarisation properties of objects from different dynamical classes. However, there are significant differences in polarisation of large and smaller size objects, and between large TNOs with water-ice and methane-ice dominated surfaces. Conclusions. We confirm the different types of polarisation phase behavior for the largest and smaller size TNOs. To explain subtle surface polarisation of Pluto, Makemake and Eris we assume that their surfaces are covered by a thin layer of hoarfrost masking the surface structure.
Published: 2012

45. TNOs are cool: A survey of the trans-Neptunian region. V. Physical characterization of 18 Plutinos using Herschel-PACS observations

Author: E. Lellouch, Miriam Rengel, Rene Duffard, Alan W. Harris, A. Delsanti, Michael Mommert, Cs. Kiss, A. Pál, Nuno Peixinho, J. L. Ortiz, Esa Vilenius, Florence Henry, T. G. Mueller, Audrey Thirouin, S. Fornasier, Paul Hartogh, Silvia Protopapa, John Stansberry, N. Szalai, Pablo Santos-Sanz, Michael Mueller, DLR Institute of Planetary Research, German Aerospace Center (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Extraterrestrische Physik (MPE), Observatorio de Coimbra, Universidade de Coimbra [Coimbra], Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Monte Carlo method, FOS: Physical sciences, Scale (descriptive set theory), Astrophysics, 01 natural sciences, Power law, Spearman's rank correlation coefficient, Photometry (optics), techniques: photometric, 0103 physical sciences, Range (statistics), infrared: planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Albedo, 13. Climate action, Space and Planetary Science, Kuiper belt: general, methods: observational, Astrophysics - Earth and Planetary Astrophysics, Data reduction
Abstract: We present Herschel PACS photometry of 18 Plutinos and determine sizes and albedos for these objects using thermal modeling. We analyze our results for correlations, draw conclusions on the Plutino size distribution, and compare to earlier results. Flux densities are derived from PACS mini scan-maps using specialized data reduction and photometry methods. In order to improve the quality of our results, we combine our PACS data with existing Spitzer MIPS data where possible, and refine existing absolute magnitudes for the targets. The physical characterization of our sample is done using a thermal model. Uncertainties of the physical parameters are derived using customized Monte Carlo methods. The correlation analysis is performed using a bootstrap Spearman rank analysis. We find the sizes of our Plutinos to range from 150 to 730 km and geometric albedos to vary between 0.04 and 0.28. The average albedo of the sample is 0.08 \pm 0.03, which is comparable to the mean albedo of Centaurs, Jupiter Family comets and other Trans-Neptunian Objects. We were able to calibrate the Plutino size scale for the first time and find the cumulative Plutino size distribution to be best fit using a cumulative power law with q = 2 at sizes ranging from 120-400 km and q = 3 at larger sizes. We revise the bulk density of 1999 TC36 and find a density of 0.64 (+0.15/-0.11) g cm-3. On the basis of a modified Spearman rank analysis technique our Plutino sample appears to be biased with respect to object size but unbiased with respect to albedo. Furthermore, we find biases based on geometrical aspects and color in our sample. There is qualitative evidence that icy Plutinos have higher albedos than the average of the sample., Comment: 18 pages, 8 figures, 8 tables, accepted for publication in A&A
Published: 2012

46. The properties of asteroid (2867) Steins from Spitzer Space Telescope observations and OSIRIS shape reconstruction

Author: Laurent Jorda, Philippe Lamy, S. Fornasier, Olivier Groussin, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Infrared, Comet, Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, Spitzer Space Telescope, 13. Climate action, Space and Planetary Science, Planet, Asteroid, 0103 physical sciences, Emissivity, Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; Aims. We report on the thermal properties and composition of asteroid (2867) Steins derived from an analysis of new Spitzer Space Telescope (SST) observations performed in March 2008, in addition to previously published SST observations performed in November 2005. Methods. We consider the three-dimensional shape model and photometric properties derived from OSIRIS images obtained during the flyby of the Rosetta spacecraft in September 2008, which we combine with a thermal model to properly interpret the observed SST thermal light curve and spectral energy distributions. Results. We obtain a thermal inertia of 100 +/- 50 J K(-1) m(-2) s(-1/2) and a beaming factor (roughness) in the range 0.7-1.0. We confirm that the infrared emissivity of Steins is consistent with an enstatite composition. The November 2005 SST thermal light curve is most reliably interpreted by assuming inhomogeneities in the thermal properties of the surface, with two different regions of slightly different roughness, as observed on other small bodies, such as the nucleus of comet 9P/Tempel 1. Our results emphasize that the shape model is important to an accurate determination of the thermal inertia and roughness. Finally, we present temperature maps of Steins, as seen by Rosetta during its flyby, and discuss the interpretation of the observations performed by the VIRTIS and MIRO instruments.
Published: 2011

47. Images of Asteroid 21 Lutetia: A Remnant Planetesimal from the Early Solar System

Author: H. Sierks, P. Lamy, C. Barbieri, D. Koschny, H. Rickman, R. Rodrigo, M.F. A'Hearn, F. Angrilli, M.A. Barucci, J.-L. Bertaux, I. Bertini, S. Besse, B. Carry, G. Cremonese, V. Da Deppo, B. Davidsson, S. Debei, M. De Cecco, J. De Leon, F. Ferri, and S. Fornasier
Subjects: CHONDRITES, IMPACT, POROSITY, MORPHOLOGY, ROSETTA
Abstract: Images obtained by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras onboard the Rosetta spacecraft reveal that asteroid 21 Lutetia has a complex geology and one of the highest asteroid densities measured so far, 3.4 +/- 0.3 grams per cubic centimeter. The north pole region is covered by a thick layer of regolith, which is seen to flow in major landslides associated with albedo variation. Its geologically complex surface, ancient surface age, and high density suggest that Lutetia is most likely a primordial planetesimal. This contrasts with smaller asteroids visited by previous spacecraft, which are probably shattered bodies, fragments of larger parents, or reaccumulated rubble piles.
Published: 2011

48. A collision in 2009 as the origin of the debris trail of asteroid P/2010 A2

Author: C. Snodgrass, C. Tubiana, J.-B. Vincent, H. Sierks, S. Hviid, R. Moissl, H. Boehnhardt, C. Barbieri, D. Koschny, P. Lamy, H. Rickman, R. Rodrigo, B. Carry, S.C. Lowry, R.J.M. Laird, P.R. Weissman, A. Fitzsimmons, S. Marchi, the OSIRIS team ( M. A'Hearn, F. Angrilli, A. Barucci, J.-L. Bertaux, G. Cremonese, V. Da Deppo, B. Davidsson, S. Debei, M. De Cecco, S. Fornasier, M. Fulle, O. Groussin, P. Gutiérrez, W.-H. Ip, L. Jorda, H. U. Keller, J. Knollenberg, J. R Kramm, E. Kuehrt, M. Kueppers, L. M. Lara, M. Lazzarin, J. López, F. Marzari, H. Michalik, G. Naletto, L. Sabau, N. Thomas, K.-P. Wenzel), Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, media_common.quotation_subject, FOS: Physical sciences, asteroidi, 01 natural sciences, comet, 0103 physical sciences, Rosetta mission, Eccentricity (behavior), Osiris images, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), Multidisciplinary, asteroid, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy, Collision, Debris, Asteroid P/2010 A2, Orbit, Planetary science, Asteroid, Asteroid belt, Geology, Astrophysics - Earth and Planetary Astrophysics, collision
Abstract: The peculiar object P/2010 A2 was discovered by the LINEAR near-Earth asteroid survey in January 2010 and given a cometary designation due to the presence of a trail of material, although there was no central condensation or coma. The appearance of this object, in an asteroidal orbit (small eccentricity and inclination) in the inner main asteroid belt attracted attention as a potential new member of the recently recognized class of 'Main Belt Comets' (MBCs). If confirmed, this new object would greatly expand the range in heliocentric distance over which MBCs are found. Here we present observations taken from the unique viewing geometry provided by ESA's Rosetta spacecraft, far from the Earth, that demonstrate that the trail is due to a single event rather than a period of cometary activity, in agreement with independent results from the Hubble Space Telescope (HST). The trail is made up of relatively large particles of millimetre to centimetre size that remain close to the parent asteroid. The shape of the trail can be explained by an initial impact ejecting large clumps of debris that disintegrated and dispersed almost immediately. We determine that this was an asteroid collision that occurred around February 10, 2009., Comment: Published in Nature on 14/10/2010. 25 pages, includes supplementary material
Published: 2010

49. Puzzling asteroid 21 Lutetia: our knowledge prior to the Rosetta fly-by

Author: I. N. Belskaya, S. Fornasier, Yu. N. Krugly, V. G. Shevchenko, N. M. Gaftonyuk, M. A. Barucci, M. Fulchignoni, R. Gil-Hutton, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institute of Astronomy, Kharkiv National University, Université Paris Cité (UPCité), Crimean Astrophysical Observatory (CrAO), and Complejo Astronómico El Leoncito (CASLEO)
Subjects: Absolute magnitude, Materials science, 010504 meteorology & atmospheric sciences, Ciencias Físicas, FOS: Physical sciences, Astrophysics, 01 natural sciences, Photometry, purl.org/becyt/ford/1 [https], Impact crater, Chondrite, 0103 physical sciences, Polarimetry, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Minor planets, Astronomy and Astrophysics, purl.org/becyt/ford/1.3 [https], Phase curve, Polarization (waves), Regolith, Asteroids, Astronomía, Meteorite, 13. Climate action, Space and Planetary Science, Asteroid, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], CIENCIAS NATURALES Y EXACTAS, Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims. A wide observational campaign was carried out in 2004–2009 that aimed to complete the ground-based investigation of Lutetia prior to the Rosetta fly-by in July 2010. Methods. We obtained BVRI photometric and V-band polarimetric measurements over a wide range of phase angles, and visible and infrared spectra in the 0.4–2.4 μm range. We analyze them with previously published data to retrieve information about Lutetia's surface properties. Results. Values of lightcurve amplitudes, absolute magnitude, opposition effect, phase coefficient, and BVRI colors of Lutetia surface seen at near pole-on aspect are determined. We define more precisely parameters of polarization phase curve and show their distinct deviation from any other moderate-albedo asteroid. An indication of possible variations in both polarization and spectral data across the asteroid surface are found. To explain features found by different techniques, we propose that (i) Lutetia has a non-convex shape, probably due to a large crater, and heterogeneous surface properties probably related to surface morphology; (ii) at least part of the surface is covered by a fine-grained regolith of particle size smaller than 20 μm; (iii) the closest meteorite analogues of Lutetia's surface composition are particular types of carbonaceous chondrites, or Lutetia has specific surface composition that is not representative among studied meteorites. Fil: Belskaya, I. N.. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia. Kharkiv Karazin National University; Ucrania Fil: Fornasier, S.. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia. Université Paris Diderot - Paris 7; Francia Fil: Krugly, Yu N.. Kharkiv Karazin National University; Ucrania Fil: Shevchenko, V. G.. Kharkiv Karazin National University; Ucrania Fil: Gaftonyuk, N. M.. Crimean Astrophysical Observatory; Ucrania Fil: Barucci, M. A.. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia Fil: Fulchignoni, M.. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia. Université Paris Diderot - Paris 7; Francia Fil: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentina
Published: 2010

50. 'TNOs are Cool': A survey of the trans-Neptunian region. I. Results from the Herschel science demonstration phase (SDP)

Author: B. M. Swinyard, Miriam Rengel, L. M. Lara, T. G. Mueller, Paul Hartogh, S. Fornasier, R. Moreno, Nicolas Thomas, Esa Vilenius, Olivier Hainaut, Daniel Hestroffer, Jonathan Horner, Pablo Santos-Sanz, E. Dotto, John Stansberry, David Trilling, A. Delsanti, M. R. Kidger, P. J. Gutierrez, Tanya Lim, Rene Duffard, Alain Doressoundiram, J. Crovisier, Michael Mueller, Florence Henry, Michael Mommert, Pedro Lacerda, Cs. Kiss, Olivier Groussin, Audrey Thirouin, Alan W. Harris, Silvia Protopapa, Antonella Barucci, J. L. Ortiz, E. Lellouch, Max-Planck-Institut für Extraterrestriche Physik (MPE), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Arizona (UoA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics and Astronomy, Durham University, Queen's University [Belfast] (QUB), Space Science and Technology Department, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon UK, Department of Physics and Astronomy, Northern Arizona University, Flagstaff, INAF-Osservatorio Astronomico di Roma (INAF-OAR), European Southern Observatory (ESO), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Herschel Science Center, ESAC/ESA, University of Bern (UBERN), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Probabilités et Modèles Aléatoires (LPMA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Sonnensystemforschung (MPS), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Color temperature, 01 natural sciences, 0103 physical sciences, Thermal, Range (statistics), Kuiper belt: general / methods: observational / techniques: photometric / instrumentation: photometers / infrared: planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Debris disk, Mode (statistics), Astronomy and Astrophysics, Centaur, Albedo, Astrophysics - Astrophysics of Galaxies, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The goal of the Herschel Open Time Key programme "TNOs are Cool!" is to derive the physical and thermal properties for a large sample of Centaurs and trans-Neptunian objects (TNOs), including resonant, classical, detached and scattered disk objects. We present results for seven targets either observed in PACS point-source, or in mini scan-map mode. Spitzer-MIPS observations were included for three objects. The sizes of these targets range from 100 km to almost 1000 km, five have low geometric albedos below 10%, (145480) 2005 TB190 has a higher albedo above 15%. Classical thermal models driven by an intermediate beaming factor of $\eta$=1.2 or $\eta$-values adjusted to the observed colour temperature fit the multi-band observations well in most cases. More sophisticated thermophysical models give very similar diameter and albedo values for thermal inertias in the range 0-25 Jm-2s-0.5K-1, consistent with very low heat conductivities at temperatures far away from the Sun. The early experience with observing and model strategies will allow us to derive physical and thermal properties for our complete Herschel TNO sample of 140 targets as a benchmark for understanding the solar system debris disk, and extra-solar ones as well., Comment: 5 pages, 2 figures, accepted for publication in the A&A Herschel Special Issue
Published: 2010

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