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1. The Future of Planetary Defense in the Era of Advanced Surveys

Author

R. T. Daly, Timothy D. Swindle, Sean E. Marshall, Marco Delbo, A. Wong, T. Grav, Judy Pipher, Sarah Greenstreet, Alan Stern, Amy Mainzer, D. C. Hickson, Kynan H.G. Hughson, Joseph Lazio, Daniel T. Britt, B. Betts, Rosaly M. C. Lopes, Michele T. Bannister, Edgard G. Rivera-Valentín, Mario Juric, Peter Eisenhardt, Sean Carey, Walter M. Harris, James F. Bell, Joseph Masiero, Robert S. McMillan, Maria Gritsevich, Daniel J. Scheeres, Devanshu Jha, M. Bruckner, Alan W. Harris, D. Takir, C. A. Schambeau, F. Marchis, Michael C. Nolan, Flaviane Venditti, Betul Kacar, T. Okada, Yan Fernandez, P. Michel, Patrick A. Taylor, C. McMurtry, Ronald A. Fevig, William F. Bottke, P. Abell, Jennifer E.C. Scully, J. Barnes, Cristina A. Thomas, Maitrayee Bose, D. Cotto-Figueroa, J. Chesley, Anne Virkki, P. W. Chodas, Timothy Spahr, D. Mathias, Brent W. Barbee, Lance A. M. Benner, Michael W. Busch, Shantanu P. Naidu, Carol A. Raymond, Heidi B. Hammel, M. Brozovic, Željko Ivezić, Lynne Jones, E. Christensen, M. Telus, Julie Castillo-Rogez, Dante S. Lauretta, S. Sonnett, Andrew S. Rivkin, Edward L. Wright, J. Dotson, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU]Sciences of the Universe [physics], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2021

2. Particle Size-Frequency Distributions of the OSIRIS-REx Candidate Sample Sites on Asteroid (101955) Bennu

Author

J. D. P. Deshapriya, Bashar Rizk, Erica Jawin, Eric M. Sahr, Jason P. Dworkin, Jennifer Nolau, Daniella DellaGiustina, R. H. Hoover, Kevin J. Walsh, Michael C. Nolan, H. L. Enos, Catherine Elder, Stephanie J. Stewart, Stuart J. Robbins, William V. Boynton, Jacob Padilla, K. N. Burke, Dante S. Lauretta, Maurizio Pajola, Dathon Golish, Peter H. Smith, Hannah C.M. Susorney, Carina Bennett, Edward B. Bierhaus, Harold C. Connolly, Patrick Michel, Jamie Molaro, Timothy J. McCoy, Juliette I. Brodbeck, and Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France

Subjects
Nolan, rubble-pile asteroids, 010504 meteorology & atmospheric sciences, K.J, Science, J.I, et al. Particle particle size-frequency distributions, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Bierhaus, H.C, Walsh, E.B, 01 natural sciences, particle size-frequency distributions, power laws, fragmentation, M, C.A, Impact crater, Sample return mission, Connolly, 0103 physical sciences, Burke, K.N, Boynton, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, M.C, D.N, W.V, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], DellaGiustina, Brodbeck, Sampling (statistics), Geodesy, Sample (graphics), Bennett, Asteroid, [SDU]Sciences of the Universe [physics], Pajola, General Earth and Planetary Sciences, Particle, Jr, Sample collection, Frequency distribution, Geology
Abstract

International audience; We manually mapped particles ranging in longest axis from 0.3 cm to 95 m on (101955) Bennu for the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) asteroid sample return mission. This enabled the mission to identify candidate sample collection sites and shed light on the processes that have shaped the surface of this rubble-pile asteroid. Building on a global survey of particles, we used higher-resolution data from regional observations to calculate particle size-frequency distributions (PSFDs) and assess the viability of four candidate sites for sample collection (presence of unobstructed particles ≤ 2 cm). The four candidate sites have common characteristics: each is situated within a crater with a relative abundance of sampleable material. Their PSFDs, however, indicate that each site has experienced different geologic processing. The PSFD power-law slopes range from −3.0 ± 0.2 to −2.3 ± 0.1 across the four sites, based on images with a 0.01-m pixel scale. These values are consistent with, or shallower than, the global survey measurements. At one site, Osprey, the particle packing density appears to reach geometric saturation. We evaluate the uncertainty in these measurements and discuss their implications for other remotely sensed and mapped particles, and their importance to OSIRIS-REx sampling operations.

Published
2021

3. Apophis 2029: Decadal Opportunity for the Science of Planetary Defense

Author

William C. Danchi, Patrick Michel, Patrick A. Taylor, James F. Bell, Michael Marsset, Daniel J. Scheeres, Jessica M. Sunshine, Derek C. Richardson, D. Souami, William F. Bottke, Olivier S. Barnouin, J. Souchay, J. V. DeMartini, Yaeji Kim, Mirel Birlan, Terik Daly, Michael C. Nolan, Carol A. Raymond, Masatoshi Hirabayashi, Joshua T.S. Cahill, Humberto Campins, Francesca E. DeMeo, Daniel D. Durda, N. Moskovitz, Joseph A. Nuth, Donald K. Yeomans, Alex Parker, Andy Cheng, M. Brozovic, Richard P. Binzel, Ryan S. Park, Flaviane Venditti, Brent W. Barbee, P. W. Chodas, Anthony Freeman, Kim Reh, Paul Sava, Lucy F. Lim, Anne Virkki, A. C. Boley, Observatoire de Paris, Université Paris sciences et lettres (PSL), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), 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), Namur Center for Complex Systems [Namur] (NaXys), Université de Namur [Namur] (UNamur), Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Comet, Geosynchronous orbit, Potentially hazardous object, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Context (language use), Mars Exploration Program, Astrobiology, Jupiter, Planetary science, 13. Climate action, Asteroid, [SDU]Sciences of the Universe [physics], Environmental science, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; Many advancements in planetary science are achieved by seizing upon the opportunity created by rare natural events (e.g. comet Shoemaker-Levy 9 Jupiter impact; 1994) and by planned physical interactions (e.g. Deep Impact into comet Tempel 1; 2005). A forthcoming opportunity to seize upon a natural physical “experiment” occurs on April 13, 2029 with the unprecedentedly close Earth encounter by the large 340m asteroid (99942) Apophis. On that date, nature is performing the “experiment” of subjecting the physical body of Apophis to Earth’s tidal torques as it approaches to within 31,000 km of Earth’s surface, a distance that is closer than orbiting geosynchronous satellites.A potentially hazardous asteroid (PHA) as large as Apophis encountering Earth this closely (within 0.1 lunar distances) is, on average, a once-per-thousand year event. (In context, Apophis is 7 times larger and 350 times more massive than the Tunguska 1908 impactor; 5000 times more massive than Chelyabinsk 2013.) Because of this event’s incredible rarity, knowledge gained through measurements and outcomes of the Apophis 2029 “natural experiment” are clearly a decadal, if not millennial, opportunity for planetary science. Most specifically, this knowledge opportunity is for the science supporting planetary defense. Further, on April 13, 2029 all of Earth will be watching: Apophis will be visible to the naked eye speeding across the evening sky for an estimated 2 billion people spanning western Europe and northern Africa.In this White Paper we outline our current best understanding, and uncertainties, for scientific advances in the physical study of potentially hazardous asteroids that may be achievable by measuring physical changes of Apophis’ spin, surface structure, and/or shape configuration inresponse to Earth’s tidal torques. If tidal torques themselves, or surface configuration changes induce any measurable seismic vibration signal inside Apophis, a new field of asteroid seismology has the potential to be born. Over six decades of planetary science, seismology has been achieved beyond Earth for only two planetary worlds: Moon and Mars.With this White Paper, we take no position on how to implement specific investigations capable of achieving the science advances offered by the Apophis 2029 opportunity. Instead we advocate that competitive selection of investigations, be they theoretical or observational (ground-based, space-based, or in situ), be executed under the direction of NASA’s Planetary Defense Coordination Office, with a projected and perhaps necessarily augmented budget capable of supporting them. International collaboration is strongly encouraged.Thus, summarizing in four specific points, we urge the framers of the Decadal Survey to:• Recognize the decadal, if not millennial, opportunity for the science of planetary defense presented by the Apophis 2029 once-per-thousand-year “natural experiment.”• Prioritize as a top-level planetary defense science goal modeling and measuring the physical outcome on Apophis exerted by Earth’s tidal torques so as to achieve the greatest possible new insights into the physical nature, including the internal structure, of PHAs.• Recognize that time is of the essence for defining and implementing investigations of physical effects on Apophis, particularly if in situ measurements are to be considered. An Apophis 2029 Science Definition Team may be prescribed.• Recognize that the achievable knowledge of PHAs presented by the Apophis 2029 opportunity could have immeasurable benefits to the future of humanity, in the highly unlikely, but not impossible necessity to mitigate a future impact threat

Published
2021

4. Rotational states and shapes of Ryugu and Bennu: Implications for interior structure and strength

Author

Kevin J. Walsh, Daniel J. Scheeres, Gregory A. Neumann, S. Sugita, Naoyuki Hirata, Patrick Michel, James H. Roberts, Jay W. McMahon, J. R. Weirich, R. T. Daly, Naru Hirata, Robert Gaskell, S. Watanabe, Yun Zhang, Eric Palmer, Michael C. Nolan, Dante S. Lauretta, Mark E. Perry, J. A. Seabrook, Olivier S. Barnouin, M. G. Daly, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Spherical harmonics, Astronomy and Astrophysics, Geometry, Shape model, Rotation, 01 natural sciences, Asteroids, law.invention, Rotational dynamics, Space and Planetary Science, Asteroid, law, Orientation (geometry), 0103 physical sciences, Bennu, Cohesion (geology), Reflection (physics), Surface roughness, Ryugu, Hydrostatic equilibrium, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; Images of asteroids (162173) Ryugu and (101955) Bennu acquired by the Hayabusa2 and OSIRIS-REx missions, respectively, reveal rocky worlds covered in rubble. These two asteroids do not have hydrostatic shapes, indicating that they possess some internal friction and/or cohesion even if they lack tensile strength. Understanding the deviation of the surfaces of these bodies from those of idealized shapes helps constrain the mechanical properties of their interiors. Here, we focus on the feedback between YORP-induced spin-up (in which asymmetric reflection and re-emission of solar radiation from the surface systematically change the rotation rate), long-wavelength topography (which provides a structure to control the orientation), and surface roughness on Ryugu and Bennu. By performing spherical harmonic analyses of the shapes of these two asteroids, we find that although they are superficially similar, they exhibit different long-wavelength topography that implies different internal structures and rotational histories. Bennu's shape and rotation rate require a modest amount of internal strength through some combination of at least 17° of internal friction or a few Pa of cohesion, whereas Ryugu could be nearly strengthless. Bennu's longitudinal ridges make it susceptible to YORP spin-up, consistent with the observed increase in rotation rate that is not seen on Ryugu. These longitudinal ridges also suggest a heterogeneous density structure for Bennu, consistent with gravity data.

Published
2021

5. 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

6. Bennu’s near-Earth lifetime of 1.75 million years inferred from craters on its boulders

Author

M. Al Asad, Olivier S. Barnouin, P. Michel, Jamie Molaro, C. Avdellidou, Carina Bennett, E. B. Bierhaus, Dante S. Lauretta, Michael C. Nolan, Kevin J. Walsh, Harold C. Connolly, Stephen R. Schwartz, Daniella DellaGiustina, C. W. V. Wolner, Bashar Rizk, Marco Delbo, Maurizio Pajola, R. L. Ballouz, Dathon Golish, Erica Jawin, M. G. Daly, David Trang, R. T. Daly, William F. Bottke, Erik Asphaug, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Southwest Research Institute [Boulder] (SwRI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France., Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
education.field_of_study, Multidisciplinary, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Population, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Astrobiology, Impact crater, Asteroid, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Size frequency, Asteroid belt, education, 010303 astronomy & astrophysics, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

An asteroid’s history is determined in large part by its strength against collisions with other objects1,2 (impact strength). Laboratory experiments on centimetre-scale meteorites3 have been extrapolated and buttressed with numerical simulations to derive the impact strength at the asteroid scale4,5. In situ evidence of impacts on boulders on airless planetary bodies has come from Apollo lunar samples6 and images of the asteroid (25143) Itokawa7. It has not yet been possible, however, to assess directly the impact strength, and thus the absolute surface age, of the boulders that constitute the building blocks of a rubble-pile asteroid. Here we report an analysis of the size and depth of craters observed on boulders on the asteroid (101955) Bennu. We show that the impact strength of metre-sized boulders is 0.44 to 1.7 megapascals, which is low compared to that of solid terrestrial materials. We infer that Bennu’s metre-sized boulders record its history of impact by millimetre- to centimetre-scale objects in near-Earth space. We conclude that this population of near-Earth impactors has a size frequency distribution similar to that of metre-scale bolides and originates from the asteroidal population. Our results indicate that Bennu has been dynamically decoupled from the main asteroid belt for 1.75 ± 0.75 million years. Analysis of the size and depth of craters on boulders on the asteroid (101955) Bennu indicates that Bennu has been in near-Earth space for 1.75 ± 0.75 million years.

Published
2020

7. Variations in color and reflectance on the surface of asteroid (101955) Bennu

Author

Kevin J. Walsh, N. Shultz, Jian-Yang Li, L. F. Lim, K. N. Burke, Michael Daly, S. Sugita, Erica Jawin, Juliette I. Brodbeck, Dante S. Lauretta, Daniella DellaGiustina, Kris J. Becker, Tammy L. Becker, Ben Rozitis, Alexis Parkinson, Beth E. Clark, Jennifer Nolau, Carina Bennett, Amanda R. Hendrix, L. Le Corre, P. Michel, Bashar Rizk, C. W. V. Wolner, Pedro Hasselmann, Ronald-Louis Ballouz, Carl Hergenrother, David Trang, Marco Delbo, Sonia Fornasier, N. A. Porter, Eri Tatsumi, Daniel M. Applin, M. A. Barucci, C. Drouet d'Aubigny, Michael C. Nolan, Antara Sen, Maurizio Pajola, C. Avdellidou, Edward A. Cloutis, Koki Yumoto, Ellen S. Howell, J. D. Prasanna Deshapriya, Marcel Popescu, V. E. Hamilton, J. L. Rizos, Hannah Kaplan, Dathon Golish, K. L. Edmundson, Amy Simon, R. B. Van Auken, William F. Bottke, Andrew Ryan, Harold C. Connolly, M. Al Asad, Jamie Molaro, J. D. De Leon, E. B. Bierhaus, P. H. Smith, Humberto Campins, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Southwest Research Institute [Boulder] (SwRI), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Surface (mathematics), Multidisciplinary, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Multispectral image, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, Reflectivity, Texture (geology), Space weathering, Wavelength, Impact crater, 13. Climate action, Asteroid, [SDU]Sciences of the Universe [physics], 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The complex history of Bennu's surface The near-Earth asteroid (101955) Bennu is a carbon-rich body with a rubble pile structure, formed from debris ejected by an impact on a larger parent asteroid. The Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft is designed to collect a sample of Bennu's surface and return it to Earth. After arriving at Bennu, OSIRIS-REx performed a detailed survey of the asteroid and reconnaissance of potential sites for sample collection. Three papers present results from those mission phases. DellaGiustina et al. mapped the optical color and albedo of Bennu's surface and established how they relate to boulders and impact craters, finding complex evolution caused by space weathering processes. Simon et al. analyzed near-infrared spectra, finding evidence for organic and carbonate materials that are widely distributed across the surface but are most concentrated on individual boulders. Kaplan et al. examined more detailed data collected on the primary sample site, called Nightingale. They identified bright veins with a distinct infrared spectrum in some boulders, which they interpreted as being carbonates formed by aqueous alteration on the parent asteroid. Together, these results constrain Bennu's evolution and provide context for the sample collected in October 2020. Science , this issue p. eabc3660 , p. eabc3522 , p. eabc3557

Published
2020

8. Exogenic basalt on asteroid (101955) Bennu

Author

Javier Licandro, Erica Jawin, M. Al Asad, J. A. Seabrook, Michael C. Nolan, M. A. Barucci, Kevin J. Walsh, Lydia C. Philpott, G. Poggiali, Timothy J. McCoy, R. P. Binzel, Marco Delbo, C. Avdellidou, Dante S. Lauretta, Marcel Popescu, J. L. Rizos Garcia, D. C. Reuter, Ellen S. Howell, Daniella DellaGiustina, Humberto Campins, Bashar Rizk, William F. Bottke, Hannah Kaplan, Amy Simon, Harold C. Connolly, Eri Tatsumi, V. E. Hamilton, M. G. Daly, Olivier S. Barnouin, Beth E. Clark, L. Le Corre, N. A. Porter, J. de León, Ronald-Louis Ballouz, R. T. Daly, Dathon Golish, Sonia Fornasier, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and ANR-18-CE31-0014,ORIGINS,A la recherche des planétésimaux de notre système solaire(2018)

Subjects
Basalt, Planetesimal, 010504 meteorology & atmospheric sciences, Astronomy and Astrophysics, 01 natural sciences, Parent body, Astrobiology, Igneous rock, Planetary science, Meteorite, 13. Climate action, Asteroid, [SDU]Sciences of the Universe [physics], Carbonaceous chondrite, 0103 physical sciences, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

When rubble-pile asteroid 2008 TC3 impacted Earth on 7 October 2008, the recovered rock fragments indicated that such asteroids can contain exogenic material1,2. However, spacecraft missions to date have only observed exogenous contamination on large, monolithic asteroids that are impervious to collisional disruption3,4. Here, we report the presence of metre-scale exogenic boulders on the surface of near-Earth asteroid (101955) Bennu—the 0.5-km-diameter, rubble-pile target of the OSIRIS-REx mission5 that has been spectroscopically linked to the CM carbonaceous chondrite meteorites6. 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 processing7–9. 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. Six bright boulders of exotic material on near-Earth asteroid (101955) Bennu stand out from the average asteroidal surface. This unexpected record of impactors offers clues to the formation history of Bennu.

Published
2020

9. Meteoroid Impacts as a Source of Bennu's Particle Ejection Events

Author

David Vokrouhlický, Stephen R. Schwartz, Michael C. Nolan, Jamie Molaro, William F. Bottke, A. Moorhead, Dante S. Lauretta, Carl Hergenrother, Harold C. Connolly, Kevin J. Walsh, Patrick Michel, Southwest Research Institute [Boulder] (SwRI), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), and University of Arizona

Subjects
010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Noon, ejecta, 01 natural sciences, Astrobiology, Planetary Sciences: Solar System Objects, Impact crater, Geochemistry and Petrology, Impact Phenomena, Cratering, Comets, OSIRIS‐REx, Earth and Planetary Sciences (miscellaneous), impacts, meteoroids, Ejecta, Planetary Sciences: Solid Surface Planets, Research Articles, 0105 earth and related environmental sciences, Meteoroid, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Impact Phenomena, Dust, Debris, Asteroids, Surfaces, Exploration of the Activity of Asteroid (101955) Bennu, Tectonophysics, Geophysics, Atmosphere of the Moon, 13. Climate action, Space and Planetary Science, Asteroid, [SDU]Sciences of the Universe [physics], Local time, Comets: Dust Tails and Trails, Bennu, Planetary Sciences: Comets and Small Bodies, Other, Natural Hazards, Geology, Research Article
Abstract

Asteroid (101955) Bennu, a near‐Earth object with a primitive carbonaceous chondrite‐like composition, was observed by the Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer (OSIRIS‐REx) spacecraft to undergo multiple particle ejection events near perihelion between December 2018 and February 2019. The three largest events observed during this period, which all occurred 3.5 to 6 hr after local noon, placed numerous particles, Key Points Meteoroids derived from comets strike Bennu near perihelion once every 2 weeks on average with an impact kinetic energy >7,000 JThey can explain the particle sizes (

Published
2020

10. Lightcurve, Color and Phase Function Photometry of the OSIRIS-REx Target Asteroid (101955) Bennu

Author

Daniel J. Scheeres, Michael C. Nolan, Richard P. Binzel, M. A. Barucci, Daniela Lazzaro, Javier Licandro, Christian Drouet d'Aubigny, Carl Hergenrother, Dante S. Lauretta, E. C. Beshore, Edward A. Cloutis, Beth E. Clark, Humberto Campins, Bashar Rizk, Noemi Pinilla-Alonso, Patrick Michel, Economics, University of Hull, 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), Department of Geography [Winnipeg], University of Winnipeg, 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), De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Flight Dynamics and Control (University of Michigan), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Instituto de Astrofisica de Canarias (IAC), and Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, ICARUS, Rotation period, [PHYS]Physics [physics], Near-Earth object, 010504 meteorology & atmospheric sciences, biology, Synodic day, Astronomy, Astronomy and Astrophysics, biology.organism_classification, 01 natural sciences, Photometry (optics), Space and Planetary Science, Asteroid, 0103 physical sciences, Phase function, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The NASA OSIRIS-REx mission will retrieve a sample of the carbonaceous near-Earth Asteroid (101955) Bennu and return it to Earth in 2023. Photometry in the Eight Color Asteroid Survey (ECAS) filter system and Johnson–Cousins V and R filters were conducted during the two most recent apparitions in 2005/2006 and 2011/2012. Lightcurve observations over the nights of September 14–17, 2005 yielded a synodic rotation period of 4.2905 ± 0.0065 h, which is consistent with the results of Nolan et al. (2013). ECAS color measurements made during the same nights confirm the B-type classification of Clark et al. (Clark, B.E., Binzel, R.P., Howell, E.S., Cloutis, E.A., Ockert-Bell, M., Christensen, P., Barucci, M.A., DeMeo, F., Lauretta, D.S., Connolly, H., Soderberg, A., Hergenrother, C., Lim, L., Emery, J., Mueller, M. [2011]. Icarus 216, 462–475). A search for the 0.7 μm hydration feature using the method of Vilas (Vilas, F. [1994]. Icarus 111, 456–467) did not reveal its presence. Photometry was obtained over a range of phase angles from 15° to 96° between 2005 and 2012. The resulting phase function slope of 0.040 magnitudes per degree is consistent with the phase slopes of other low albedo near-Earth asteroids (Belskaya, I.N., Shevchenko, V.G. [2000]. Icarus 147, 94–105).

Published
2013

11. EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign

Author

Michael Küppers, Edith Hadamcik, Paolo Tanga, Z. Getu, J. Pittichova, Luke D. Keller, Dinesh Shenoy, M. Sato, David E. Harker, Damian J. Christian, Ray W. Russell, Terry Herter, Scott J. Wolk, Zhong-Yi Lin, Lucas Paganini, Steven B. Charnley, P. B. Nowajewski, Jérémie Boissier, J. A. Adams, R. Ligustri, B. Hausler, John K. Harmon, Urban Frisk, Michael J. Mumma, Geronimo L. Villanueva, N. Howes, Erika L. Gibb, G. Sostero, Hector Canovas, Ronald J. Vervack, Anny Chantal Levasseur-Regourd, H. L. Nordh, S. Lundin, Iain Coulson, S. F. Velichko, Jean-Baptiste Vincent, Bart Vandenbussche, Diego Rodríguez, Stefan Immler, D. A. García-Hernández, Paul Hartogh, Yunhee Choi, Lawrence H. Wasserman, T. Karlsson, S. Sosseini, W. Borghini, Terry J. Jones, Y. L. Chuang, Carey M. Lisse, C. Perrella, Y. L. Radeva, M. Hashimoto, H. Lu, Damien Hutsemekers, P. A. Yanamandra-Fischer, Åke Hjalmarson, Jacqueline V. Keane, Seiji Sugita, Matthew M. Knight, J. M. Bai, J. C. Shi, Amy J. Lovell, Takafumi Ootsubo, Stephen T. Holland, P. Chiang, Dennis Bodewits, H. Y. Hsiao, M. Yamaguchi, Cecilia Tubiana, R. A. Guillermo, Donald K. Yeomans, Henry A. Kobulnicky, Jacques Crovisier, Manuela Lippi, Karen Magee-Sauer, Naruhisa Takato, M. de Juan Ovelar, D. K. Sahu, M. Wang, Eric E. Becklin, Julie Ziffer PhD, Michael A. DiSanti, Odin Team, B. Li, Boncho P. Bonev, J. Skvarc, William T. Reach, Michael S. P. Kelley, Tony L. Farnham, Adam J. McKay, Paul R. Weissman, Stefanie N. Milam, Daisuke Kinoshita, William M. Jackson, L. Barrera, Nalin H. Samarasinha, R. Trabatti, Michaël Gillon, L. M. Lara, James M. Bauer, Mario Daniel Melita, Ludmilla Kolokolova, J. Lacruz, Slawomira Szutowicz, Dominik R. G. Schleicher, Michael L. Sitko, Pierre Colom, Jean Manfroid, E. Bryssinck, Pierre Magain, H. G. Floren, G. Sarid, A. K. Sen, Patrick A. Taylor, Colin Snodgrass, Yi-Jehng Kuan, Nicolas Biver, D. Castellano, E. Guido, F. P. Velichko, M. J. Vidal-Nunez, Bruce Swinyard, J. S. Yao, J. Watanabe, William D. Vacca, Charles E. Woodward, Marc W. Buie, M. Facchini, Mitsuhiko Honda, Javier Licandro, J. Vaubaillion, Ellen S. Howell, G. P. Tozzi, G. Milani, Jan T. Kleyna, Miriam Rengel, Yoshiharu Shinnaka, Olivier Hainaut, Wen Ping Chen, H. Mikuz, John Robert Brucato, Sarah Sonnett, Edward W. Schwieterman, C. Vinante, M. Battelino, Sona Hosseini, Karen J. Meech, G. Galli, Dariusz C. Lis, Hermann Böhnhardt, Konrad Dennerl, Anita L. Cochran, E. Mazzotta Epifani, S. V. Jeffers, Timm Riesen, K. Dewahl, Yanga R. Fernandez, Dominique Bockelée-Morvan, R. Furusho, Emmanuel Jehin, T. Yamashita, Hideyo Kawakita, Michiel Rodenhuis, Michael F. A'Hearn, W. B. Landsman, H. H. Hsieh, M. de Val-Borro, Diane H. Wooden, N. Dello Russo, Tetsuharu Fuse, M. Kreiny, P. Bacci, Walter M. Harris, H. M. Kaluna, Bhuwan C. Bhatt, Raphael Moreno, Alain Lecacheux, Harold A. Weaver, Bin Yang, A. Gersch, T. Zenn, M. Nicolini, Takuya Fujiyoshi, Michiel Min, Stephen C. Lowry, Aage Sandqvist, B. E. A. Mueller, Josep M. Trigo-Rodríguez, Nikolai Kiselev, H. Kobayashi, E. Prosperi, H. B. Hammel, Michael C. Nolan, A. Sánchez Caso, Michael R. Combi, Anthony J. Remijan, Haibin Zhao, Institute for Astronomy [Honolulu], University of Hawai‘i [Mānoa] (UHM), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Department of Astronomy [Ithaca], Cornell University [New York], Centro Astronomico di Libbiano, Associazione Astrofili Alta Valdera, Yunnan Astronomical Observatory, Chinese Academy of Sciences [Beijing] (CAS), Universidad Metropolitana de Ciencias de la Educación (UMCE), Swedish Space Corporation (SSC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Stratospheric Observatory for Infrared Astronomy, Universities Space Research Association (USRA), Indian Institute of Astrophysics (IIA), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, NASA Goddard Space Flight Center (GSFC), McDonald Observatory, University of Texas at Austin [Austin], Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Institut de Ciencies de l'Espai [Barcelona] (ICE-CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), 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), 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), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), Université Nice Sophia Antipolis (... - 2019) (UNS), 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), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, and 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)

Subjects
Rotation period, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Ciencias Físicas, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, 7. Clean energy, Astrobiology, Photometry (optics), Spitzer Space Telescope, Comet nucleus, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Cosmic dust, Physics, Astronomy, Astronomy and Astrophysics, Light curve, Misiones espaciales, Astronomía, Space and Planetary Science, Cometas, Objetos transnetptunianos, Halo, sense organs, CIENCIAS NATURALES Y EXACTAS
Abstract

Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ∼16.4 hr. Starting in 2010 August the period changed from 16.6 hr to near 19 hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO2-driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production. Fil: Meech, K. J.. Institute for Astronomy; Estados Unidos Fil: A’Hearn, M. F.. University of Maryland; Estados Unidos Fil: Adams, J. A.. Cornell University; Estados Unidos Fil: Bacci, P.. Centro Astronomico di Libbiano; Italia Fil: Bai, J.. Chinese Academy of Sciences; China Fil: Barrera, L.. Universidad Metropolitana de Ciencias de la Educacion; Chile Fil: Battelino, M.. Swedish Space Corporation; Suecia Fil: Bauer, J. M.. Jet Propulsion Laboratory; Estados Unidos Fil: Becklin, E.. Stratospheric Observatory for Infrared Astronomy; Estados Unidos Fil: Bhatt, B.. Indian Institute of Astrophysics; India Fil: Biver, N.. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia Fil: Bockelee Morvan, D.. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia Fil: Bodewits, D.. University of Maryland; Estados Unidos Fil: Bohnhardt, H.. Gobierno de la Republica Federal de Alemania. Max Planck Institut Fur Astrophysik; Alemania Fil: Boissier, J.. Inst. di Radioastronomia; Italia Fil: Bonev, B. P.. Catholic University of America; Estados Unidos Fil: Borghini, W.. Osservatorio Astronomico Naturalistico di Casasco; Italia Fil: Brucato, J. R.. Osservatorio Astrofisico di Arcetri; Italia Fil: Bryssinck, E.. Brixiis Observatory; Bélgica Fil: Buie. M. W.. Southwest Research Institute; Estados Unidos Fil: Canovas, H.. Utrecht University; Países Bajos Fil: Castellano, D.. Unione Astrofili Italiani; Italia Fil: Charnley, S. B.. National Aeronautics And Space Administration; Estados Unidos Fil: Chen, W. P.. National Taiwan Normal University; Corea del Sur Fil: Chiang, P.. Korea Astronomy and Space Science Institute; Corea del Sur Fil: Choi, Y. J.. Korea Astronomy and Space Science Institute; Corea del Sur Fil: Christian, D. J.. California State University; Estados Unidos Fil: Chuang, Y. L.. National Taiwan Normal University; Corea del Sur Fil: Cochran, A. L.. University of Texas; Estados Unidos Fil: Melita, Mario Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina

Published
2011

12. IS THERE A NORTH-SOUTH DIVIDE IN SELF-EMPLOYMENT IN ENGLAND?

Author

Michael A. Nolan, Felix R. FitzRoy, Andrew Burke, School of Management, Cranfield University, Economics, University of St Andrews [Scotland], and University of Hull

Subjects
Employment Research, Economics, Raumplanung und Regionalforschung, Decomposition analysis, 0502 economics and business, ddc:330, Sociology, Social Sciences & Humanities, 050207 economics, ddc:710, Arbeitsmarkt- und Berufsforschung, General Environmental Science, Job creation, Landscaping and area planning, Städtebau, Raumplanung, Landschaftsgestaltung, 05 social sciences, Area Development Planning, Regional Research, General Social Sciences, Wirtschaft, Economy, Regional variation, Regional studies, 8. Economic growth, Demographic economics, 050203 business & management, Self-employment, North–South divide
Abstract

Burke A. E., Fitzroy F. R. and Nolan M. A. Is there a North–South divide in self-employment in England?, Regional Studies. Using decomposition analysis, the paper investigates why Northern England has fewer but higher performing self-employed individuals than the South. It is found that the causes are mainly structural differences rather than regional variation in individual characteristics. There are more self-employed individuals in the South, but on average they create fewer jobs. Post-compulsory education has a strong negative effect on the probability of self-employment in the South, probably due to better employment opportunities there, but little influence in the North. Education has some positive effects on job creation by entrepreneurs in both regions. Aggregate studies might thus give misleading results. Burke A. E., Fitzroy F. R. et Nolan M. A. Est-il une fracture de Nord Sud en ce qui concerne les emplois independants en Angleterre?, Regional Studies. Se pliant sur une analyse par decompositio...

Published
2009

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