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1. Action Research in Astronomy and Ecology: The observatory of the night environment in Grenoble

Author

Milli, Julien, Boribon, Merlin, Malbet, Fabien, Deverchere, Philippe, Drillat, Benjamin, Falque, Baptiste, and Colas, Francois

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Physics and Society
Abstract

We present an example of low-carbon research activity carried out by astrophysicists and focused on ecology and environmental protection, with direct impacts on territories and society. This project serves as an illustration of action research for an astrophysics lab in the context of the current ecological crisis., Comment: 4 pages, 3 figures, proceeding of Societe Francaise d'Astronomie et d'Astrophysique (SF2A) 2024

Published
2024

2. The Winchcombe Fireball -- that Lucky Survivor

Author

McMullan, Sarah, Vida, Denis, Devillepoix, Hadrien A. R., Rowe, Jim, Daly, Luke, King, Ashley J., Cupák, Martin, Howie, Robert M., Sansom, Eleanor K., Shober, Patrick, Towner, Martin C., Anderson, Seamus, McFadden, Luke, Horák, Jana, Smedley, Andrew R. D., Joy, Katherine H., Shuttleworth, Alan, Colas, Francois, Zanda, Brigitte, O'Brien, Áine C., McMullan, Ian, Shaw, Clive, Suttle, Adam, Suttle, Martin D., Young, John S., Campbell-Burns, Peter, Kacerek, Richard, Bassom, Richard, Bosley, Steve, Fleet, Richard, Jones, Dave, McIntyre, Mark, James, Nick, Robson, Derek, Dickinson, Paul, Bland, Philip A., and Collins, Gareth S.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

On February 28, 2021, a fireball dropped $\sim0.6$ kg of recovered CM2 carbonaceous chondrite meteorites in South-West England near the town of Winchcombe. We reconstruct the fireball's atmospheric trajectory, light curve, fragmentation behaviour, and pre-atmospheric orbit from optical records contributed by five networks. The progenitor meteoroid was three orders of magnitude less massive ($\sim13$ kg) than any previously observed carbonaceous fall. The Winchcombe meteorite survived entry because it was exposed to a very low peak atmospheric dynamic pressure ($\sim0.6$ MPa) due to a fortuitous combination of entry parameters, notably low velocity (13.9 km/s). A near-catastrophic fragmentation at $\sim0.07$ MPa points to the body's fragility. Low entry speeds which cause low peak dynamic pressures are likely necessary conditions for a small carbonaceous meteoroid to survive atmospheric entry, strongly constraining the radiant direction to the general antapex direction. Orbital integrations show that the meteoroid was injected into the near-Earth region $\sim0.08$ Myr ago and it never had a perihelion distance smaller than $\sim0.7$ AU, while other CM2 meteorites with known orbits approached the Sun closer ($\sim0.5$ AU) and were heated to at least 100 K higher temperatures., Comment: Accepted for publication in MAPS

Published
2023

3. Luminous efficiency based on FRIPON meteors

Author

Drolshagen, Esther, Ott, Theresa, Koschny, Detlef, Drolshagen, Gerhard, Vaubaillon, Jeremie, Colas, Francois, Trigo-Rodriguez, Josep Maria, Zanda, Brigitte, Bouley, Sylvain, Jeanne, Simon, Malgoyre, Adrien, Birlan, Mirel, Vernazza, Pierre, Gardiol, Daniele, Nedelcu, Dan Alin, Rowe, Jim, Forcier, Mathieu, Asensio, Eloy Peña, Lamy, Herve, Ferrière, Ludovic, Barghini, Dario, Carbognani, Albino, Di Martino, Mario, Rasetti, Stefania, Valsecchi, Giovanni Battista, Volpicelli, Cosimo Antonio, Di Carlo, Matteo, Knapic, Cristina, Pratesi, Giovanni, Riva, Walter, Stirpe, Giovanna M., Zorba, Sonia, Hernandez, Olivier, Jehin, Emmanuel, Jobin, Marc, King, Ashley, Sanchez-Lavega, Agustin, Toni, Andrea, and Poppe, Björn

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

In meteor physics the luminous efficiency ${\tau}$ is used to convert the meteor's magnitude to the corresponding meteoroid's mass. However, lack of sufficiently accurate verification methods or adequate laboratory tests leave this parameter to be controversially discussed. In this work meteor/fireball data obtained by the Fireball Recovery and InterPlanetary Observation Network (FRIPON) was used to calculate the masses of the pre-atmospheric meteoroids which could in turn be compared to the meteor brightnesses to assess their luminous efficiencies. For that, deceleration-based formulas for the mass computation were used. We have found ${\tau}$-values, as well as the shape change coefficients, of 294 fireballs with determined masses in the range of $10^{-6}$ kg - $100$ kg. The derived ${\tau}$-values have a median of ${\tau}_{median}$ = 2.17 %. Most of them are on the order of 0.1 % - 10 %. We present how our values were obtained, compare them with data reported in the literature, and discuss several methods. A dependence of ${\tau}$ on the pre-atmospheric velocity of the meteor, $v_e$, is noticeable with a relation of ${\tau}=0.0023 \cdot v_e^{2.3}$. The higher luminous efficiency of fast meteors could be explained by the higher energy released. Fast meteoroids produce additional emission lines that radiate more efficiently in specific wavelengths due to the appearance of the so-called second component of higher temperature. Furthermore, a dependence of ${\tau}$ on the initial meteoroid mass, $M_e$, was found, with negative linear behaviour in log-log space: ${\tau}=0.48 \cdot M_e^{-0.47}$. This implies that the radiation of smaller meteoroids is more efficient.

Published
2020
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4. Size and Shape Constraints of (486958) Arrokoth from Stellar Occultations

Author

Buie, Marc W., Porter, Simon B., Tamblyn, Peter, Terrell, Dirk, Parker, Alex Harrison, Baratoux, David, Kaire, Maram, Leiva, Rodrigo, Verbiscer, Anne J., Zangari, Amanda M., Colas, François, Diop, Baïdy Demba, Samaniego, Joseph I., Wasserman, Lawrence H., Benecchi, Susan D., Caspi, Amir, Gwyn, Stephen, Kavelaars, J. J., Uría, Adriana C. Ocampo, Rabassa, Jorge, Skrutskie, M. F., Soto, Alejandro, Tanga, Paolo, Young, Eliot F., Stern, S. Alan, Andersen, Bridget C., Pérez, Mauricio E. Arango, Arredondo, Anicia, Artola, Rodolfo Alfredo, Bâ, Abdoulaye, Ballet, Romuald, Blank, Ted, Bop, Cheikh Tidiane, Bosh, Amanda S., López, Matías Aarón Camino, Carter, Christian M., Castro-Chacón, J. H., Desprez, Alfonso Caycedo, Guerra, Nicolás Caycedo, Conard, Steven J., Dauvergne, Jean-Luc, Dean, Bryan, Dean, Michelle, Desmars, Josselin, Dieng, Abdou Lahat, Dieng, Mame Diarra Bousso, Diouf, Omar, Dorego, Gualbert Séraphin, Dunham, David W., Dunham, Joan, Luca, Hugo A. Durantini, Edwards, Patrick, Erasmus, Nicolas, Faye, Gayane, Faye, Mactar, Ferrario, Lucas Ezequiel, Ferrell, Chelsea L., Finley, Tiffany J., Fraser, Wesley C., Friedli, Alison J., Serna, Julián Galvez, Garcia-Migani, Esteban A., Genade, Anja, Getrost, Kai, Gil-Hutton, Ricardo A., Gimeno, German N., Golub, Eli Joseph, Murillo, Giovanni Francisco González, Grusin, Michael D., Gurovich, Sebastian, Hanna, William H., Henn, Santiago M., Hinton, P. C., Hughes, Paul J., Josephs Jr, John David, Joya, Raul, Kammer, Joshua A., Keeney, Brian A., Keller, John M., Kramer, Emily A., Levine, Stephen E., Lisse, Carey M., Lovell, Amy J., Mackie, Jason A., Makarchuk, Stanislav, Manzano, Luis E., Mbaye, Salma Sylla, Mbaye, Modou, Melia, Raul Roberto, Moreno, Freddy, Moss, Sean K., Ndaiye, Diene, Ndiaye, Mapathe, Nelson, Matthew J., Olkin, Catherine B., Olsen, Aart M., Moreno, Victor Jonathan Ospina, Pasachoff, Jay M., Pereyra, Mariana Belen, Person, Michael J., Pinzón, Giovanni, Pulver, Eduardo Alejandro, Quintero, Edwin A., Regester, Jeffrey R., Resnick, Aaron Caleb, Reyes-Ruiz, Mauricio, Rolfsmeier, Alex D., Ruhland, Trina R., Salmon, Julien, Santos-Sanz, Pablo, Santucho, Marcos Ariel, Niño, Diana Karina Sepúlveda, Sickafoose, Amanda A., Silva, José S., Singer, Kelsi N., Skipper, Joy N., Slivan, Stephen M., Smith, Rose J. C., Spagnotto, Julio C., Stephens, Andrew W., Strabala, Samuel D., Tamayo, Francisco J., Throop, Henry B., Cañas, Andrés David Torres, Toure, Labaly, Traore, Alassane, Tsang, Constantine C. C., Turner, Jake D., Vanegas, Santiago, Venable, Roger, Wilson, John C., Zuluaga, Carlos A., and Zuluaga, Jorge I.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We present the results from four stellar occultations by (486958) Arrokoth, the flyby target of the New Horizons extended mission. Three of the four efforts led to positive detections of the body, and all constrained the presence of rings and other debris, finding none. Twenty-five mobile stations were deployed for 2017 June 3 and augmented by fixed telescopes. There were no positive detections from this effort. The event on 2017 July 10 was observed by SOFIA with one very short chord. Twenty-four deployed stations on 2017 July 17 resulted in five chords that clearly showed a complicated shape consistent with a contact binary with rough dimensions of 20 by 30 km for the overall outline. A visible albedo of 10% was derived from these data. Twenty-two systems were deployed for the fourth event on 2018 Aug 4 and resulted in two chords. The combination of the occultation data and the flyby results provides a significant refinement of the rotation period, now estimated to be 15.9380 $\pm$ 0.0005 hours. The occultation data also provided high-precision astrometric constraints on the position of the object that were crucial for supporting the navigation for the New Horizons flyby. This work demonstrates an effective method for obtaining detailed size and shape information and probing for rings and dust on distant Kuiper Belt objects as well as being an important source of positional data that can aid in spacecraft navigation that is particularly useful for small and distant bodies., Comment: Submitted to Astronomical Journal (revised); 40 pages, 13 figures, 9 tables

Published
2019
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5. A little tour across the wonderful realm of meteor radiometry

Author

Rault, Jean-Louis and Colas, François

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

This paper describes the path strewn with pitfalls encountered during the development of a large dynamic range and very fast radiometer designed to precisely observe the meteor light curves. A small series production of a finalized version of the current prototype should accompany some video cameras from the FRIPON network., Comment: To be published in the Proceedings of the International Meteor Conference, Bollmannsruh, Germany,3 to 6 October 2019

Published
2019

6. A New, Long-Lived, Jupiter Mesoscale Wave Observed at Visible Wavelengths

Author

Simon, Amy A., Hueso, Ricardo, Inurrigarro, Peio, Sanchez-Lavega, Agustin, Morales-Juberias, Raul, Cosentino, Richard, Fletcher, Leigh N., Wong, Michael H., Hsu, Andrew I., de Pater, Imke, Orton, Glenn S., Colas, Francois, Delcroix, Marc, Peach, Damian, and Gomez-Forrellad, Josep-Maria

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Small-scale waves were observed along the boundary between Jupiter's North Equatorial Belt and North Tropical Zone, ~16.5{\deg} N planetographic latitude in Hubble Space Telescope data in 2012 and throughout 2015 to 2018, observable at all wavelengths from the UV to the near IR. At peak visibility, the waves have sufficient contrast (~10%) to be observed from ground-based telescopes. They have a typical wavelength of about 1.2{\deg} (1400 km), variable-length wave trains, and westward phase speeds of a few m/s or less. New analysis of Voyager 2 data shows similar wave trains over at least 300 hours. Some waves appear curved when over cyclones and anticyclones, but most are straight, but tilted, shifting in latitude as they pass vortices. Based on their wavelengths, phase speeds, and faint appearance at high-altitude sensitive passbands, the observed NEB waves are consistent with inertia-gravity waves at the 500-mbar pressure level, though formation altitude is not well constrained. Preliminary General Circulation Model simulations generate inertia-gravity waves from vortices interacting with the environment and can reproduce the observed wavelengths and orientations. Several mechanisms can generate these waves, and all may contribute: geostrophic adjustment of cyclones; cyclone/anticyclone interactions; wind interactions with obstructions or heat pulses from convection; or changing vertical wind shear. However, observations also show that the presence of vortices and/or regions of convection are not sufficient by themselves for wave formation, implying that a change in vertical structure may affect their stability, or that changes in haze properties may affect their visibility., Comment: Astronomical Journal, accepted

Published
2018
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7. Fine-scale observations of the Doppler frequency shifts affecting meteor head radio echoes

Author

Rault, Jean-Louis, Birlan, Mirel, Blanpain, Cyril, Bouley, Sylvain, Caminade, Stéphane, Colas, François, Gattacceca, Jérôme, Jeanne, Simon, Lecubin, Julien, Malgoyre, Adrien, Marmo, Chiara, Vaubaillon, Jérémie, Vernazza, Pierre, and Zanda, Brigitte

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

The French FRIPON (Fireball Recovery and Interplanetary Observation Network) programme relies on a video cameras network associated to radio sensors running in a radar multistatic configuration to observe fireballs and to determine meteoroid accurate orbits and potential meteorites strewnfields. This paper focuses on some peculiar phenomena observed with radio means during the final phase of the meteors flight, Comment: International Meteor Conference 2017

Published
2018

8. Multi-instrumental observations of the 2014 Ursid meteor outburst

Author

Moreno-Ibáñez, Manuel, Trigo-Rodríguez, Josep Ma., Madiedo, José María, Vaubaillon, Jérémie, Williams, Iwan P., Gritsevich, Maria, Morillas, Lorenzo G., Blanch, Estefanía, Pujols, Pep, Colas, François, and Dupouy, Philippe

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

The Ursid meteor shower is an annual shower that usually shows little activity. However, its Zenith Hourly Rate sometimes increases, usually either when its parent comet, 8P/Tuttle, is close to its perihelion or its aphelion. Outbursts when the comet is away from perihelion are not common and outburst when the comet is close to aphelion are extremely rare. The most likely explanation offered to date is based on the orbital mean motion resonances. The study of the aphelion outburst of December 2000 provided a means of testing that hypothesis. A new aphelion outburst was predicted for December 2014. The Spanish Meteor Network in collaboration with the French Fireball Recovery and InterPlanetary Observation Network set up a campaign to monitor this outburst and eventually retrieve orbital data that expands and confirms previous preliminary results and predictions. Despite unfavourable weather conditions over the South of Europe over the relevant time period precise trajectories from multi-station meteor data recorded over Spain were obtained, as well as orbital and radiant information for four Ursid meteors. The membership of these four meteors to the expected dust trails that were to provoke the outburst is discussed, and we characterize the origin of the outburst in the dust trail produced by the comet in the year 1392 A.D., Comment: 12 pages, 6 figures, 7 tables

Published
2017
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10. Genomic Reconstruction of the Successful Establishment of a Feralized Bovine Population on the Subantarctic Island of Amsterdam.

Author

Gautier, Mathieu, Micol, Thierry, Camus, Louise, Moazami-Goudarzi, Katayoun, Naves, Michel, Guéret, Elise, Engelen, Stefan, Lemainque, Arnaud, Colas, François, Flori, Laurence, and Druet, Tom

Subjects
GENETIC load, WHOLE genome sequencing, GENETIC variation, NERVOUS system, INBREEDING, CATTLE genetics
Abstract

The feral cattle of the subantarctic island of Amsterdam provide an outstanding case study of a large mammalian population that was established by a handful of founders and thrived within a few generations in a seemingly inhospitable environment. Here, we investigated the genetic history and composition of this population using genotyping and sequencing data. Our inference showed an intense but brief founding bottleneck around the late 19th century and revealed contributions from European taurine and Indian Ocean Zebu in the founder ancestry. Comparative analysis of whole-genome sequences further revealed a moderate reduction in genetic diversity despite high levels of inbreeding. The brief and intense bottleneck was associated with high levels of drift, a flattening of the site frequency spectrum and a slight relaxation of purifying selection on mildly deleterious variants. Unlike some populations that have experienced prolonged reductions in effective population size, we did not observe any significant purging of highly deleterious variants. Interestingly, the population's success in the harsh environment can be attributed to preadaptation from their European taurine ancestry, suggesting no strong bioclimatic challenge, and also contradicting evidence for insular dwarfism. Genome scan for footprints of selection uncovered a majority of candidate genes related to nervous system function, likely reflecting rapid feralization driven by behavioral changes and complex social restructuring. The Amsterdam Island cattle offers valuable insights into rapid population establishment, feralization, and genetic adaptation in challenging environments. It also sheds light on the unique genetic legacies of feral populations, raising ethical questions according to conservation efforts. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Search for companions around Sirius

Author

Bonnet-Bidaud, Jean-Marc, Colas, Francois, and Lecacheux, Jean

Subjects
Astrophysics
Abstract

Since the discovery of Sirius-B about 130 yr ago, there have been several claims of a possible second companion around the brightest star Sirius-A. Such a companion could, in particular, be responsible of the suspected colour change of the star, now strongly suggested from two independent historical sources. We reported here on a new observation of the sky region around Sirius, to search for such a companion, using a coronographic device. By comparison of the new stellar field with a similar image obtained by us $\sim$13 yr ago and using the Sirius proper motion, we are able to eliminate the most obvious companion candidates down to a magnitude m$_v$$\sim$17 in a field from 30 arcsec to 2.5 arcmin of the central star. None of the visible stars appears consistent in magnitude and colours with what expected from current theoretical models and observations of low-mass stars. From the study of the same field, it is also shown that the Sirius companion, consistently reported by observers during the years 1920-1930, is most probably an unrelated m$_g$$\simeq$12 background star, now $\sim$ 1 arcmin away but located precisely on the Sirius proper motion trajectory. The closest apparent conjunction with Sirius was realized in 1937 with a minimum angular distance of 6.9 arcsec, of the same order than the Sirius A-B binary separation. The reported observations do not eliminate the possibility of a second companion but now confined the search to the more central 30 arcsec region around Sirius. In particular, the existence of a long period companion cannot definitively be ruled out since the arbitrary orientation of the orbit can yield an observed projected position on sky inside this more central region., Comment: 6 pages, 4 figures, published in Astronomy and Astrophysics

Published
2000

14. FRIPON grazing fireball event detected by MOROI cameras

Author

Boaca, Ioana Lucia, Gritsevich, Maria, Nedelcu, Alin, Boaca, Tudor, Colas, François, Malgoyre, Adrien, Zanda, Brigitte, and Vernazza, Pierre

Abstract

In this work we present one of the most spectacular fireball events detected by the MOROI (Meteorite Orbits Reconstruction by Optical Imaging) (Nedelcu et al. 2018) part of the FRIPON (Fireball Recovery and Inter Planetary Observation Network) (Colas et al. 2020) all-sky camera network. The meteor was recorded on 3rd of November 2022 at 01:30:03 UT by cameras Bacau (ROBC01), Paulesti (ROPH01) and Obarsia Noua (ROOT01). The ablation phenomenon started at an altitude of 95 km above the sea level and the meteoroid fainted/ left the Earth’s atmosphere at 90.6 km. The fireball event had a duration of 12.22 seconds. We determine the physical parameters of the meteoroid resulting from the luminous trajectory (Gritsevich 2008, 2009, Sansom et al. 2019, Boaca et al. 2022). We compute its mass, its velocity and determine the orbital elements using Meteor Toolkit (Dmitriev et al. 2015). Boaca I., et al. (2022), ApJ, 936, 150.Colas, F., et al. (2020), A&A, 644, A53.Dmitriev, V., et al. (2015), PSS, 117, 223-235.Gritsevich, M. I. (2008), DokPh, 53, 97.Gritsevich, M. (2009), AdSpR, 44, 323.Nedelcu, D. A., et al. (2018), RoAJ, 28, 57.Sansom, E. K., et al. 2019, ApJ, 885, 115.Acknowledgement.The work of IB and AN was partially supported by a grant of the Ministry of National Education and Scientific Research, PNIII-P2-1214/25.10.2021, program no. 36SOL/2021. MG acknowledges the Academy of Finland project no. 325806 (PlanetS)., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

17. Impact of Chlorophyll Shading on the Peruvian Upwelling System

Author

Echevin, Vincent, Hauschildt, Jaard, Colas, François, Thomsen, Soeren, Aumont, Olivier, Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Nucleus for European Modeling of the Ocean (NEMO R&D ), LEFE-GMMC Senox project., Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)

Subjects
[PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]
Abstract

International audience; The influence of chlorophyll shading on ocean dynamics has been usually disregarded in eastern boundary upwelling systems modeling studies in spite of their very high primary productivity. Here, we study how this effect impacts on the Peru upwelling system using a regional mesoscale-resolving physical biogeochemical coupled model. We show that the shading effect leads to a surface cooling of up to 1°C on the shelf due to subsurface cooling of the source waters during their transit toward the shelf. The shading effect leads to a more realistic subsurface stratification, a slowdown of the alongshore currents, and a shoaling of the oxycline. Impacts on the regional model biases show that the shading effect needs to be taken into account in both physical and coupled physical-biogeochemical regional models of upwelling systems.

Published
2021

18. Evidence for differentiation of the most primitive small bodies

Author

Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Carry, Benoît, Vernazza, Pierre, Vachier, Frédéric, Neveu, Marc, Berthier, Jérôme, Hanuš, Josef, Ferrais, Marin, Jorda, Laurent, Marsset, Michaël, Viikinkoski, Matti, Bartczak, Przemyslaw, Behrend, Raoul, Benkhaldoun, Zouhair, Birlan, Mirel, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Drouard, Alexis, Dudziński, Grzegorz, Desmars, Josselin, Dumas, Christophe, Ďurech, Josef, Fétick, Romain, Fusco, Thierry, Grice, Jonny, Jehin, Emmanuel, Kaasalainen, Mikko, Kryszczynska, Agnieszka, Lamy, Philippe, Marchis, Franck, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Pajuelo, Myriam, Podlewska-Gaca, Edyta, Rambaux, Nicolas, Santana-Ros, Toni, Storrs, Alexander, Tanga, Paolo, Vigan, Arthur, Warner, Brian, Wieczorek, Mark, Witasse, Olivier, Yang, Bin, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Carry, Benoît, Vernazza, Pierre, Vachier, Frédéric, Neveu, Marc, Berthier, Jérôme, Hanuš, Josef, Ferrais, Marin, Jorda, Laurent, Marsset, Michaël, Viikinkoski, Matti, Bartczak, Przemyslaw, Behrend, Raoul, Benkhaldoun, Zouhair, Birlan, Mirel, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Drouard, Alexis, Dudziński, Grzegorz, Desmars, Josselin, Dumas, Christophe, Ďurech, Josef, Fétick, Romain, Fusco, Thierry, Grice, Jonny, Jehin, Emmanuel, Kaasalainen, Mikko, Kryszczynska, Agnieszka, Lamy, Philippe, Marchis, Franck, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Pajuelo, Myriam, Podlewska-Gaca, Edyta, Rambaux, Nicolas, Santana-Ros, Toni, Storrs, Alexander, Tanga, Paolo, Vigan, Arthur, Warner, Brian, Wieczorek, Mark, Witasse, Olivier, and Yang, Bin

Abstract

Context. Dynamical models of Solar System evolution have suggested that the so-called P- and D-type volatile-rich asteroids formed in the outer Solar System beyond Neptune’s orbit and may be genetically related to the Jupiter Trojans, comets, and small Kuiper belt objects (KBOs). Indeed, the spectral properties of P- and D-type asteroids resemble that of anhydrous cometary dust. Aims. We aim to gain insights into the above classes of bodies by characterizing the internal structure of a large P- and D-type asteroid. Methods. We report high-angular-resolution imaging observations of the P-type asteroid (87) Sylvia with the Very Large Telescope Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument. These images were used to reconstruct the 3D shape of Sylvia. Our images together with those obtained in the past with large ground-based telescopes were used to study the dynamics of its two satellites. We also modeled Sylvia’s thermal evolution. Results. The shape of Sylvia appears flattened and elongated (a/b ~1.45; a/c ~1.84). We derive a volume-equivalent diameter of 271 ± 5 km and a low density of 1378 ± 45 kg m−3. The two satellites orbit Sylvia on circular, equatorial orbits. The oblateness of Sylvia should imply a detectable nodal precession which contrasts with the fully-Keplerian dynamics of its two satellites. This reveals an inhomogeneous internal structure, suggesting that Sylvia is differentiated. Conclusions. Sylvia’s low density and differentiated interior can be explained by partial melting and mass redistribution through water percolation. The outer shell should be composed of material similar to interplanetary dust particles (IDPs) and the core should be similar to aqueously altered IDPs or carbonaceous chondrite meteorites such as the Tagish Lake meteorite. Numerical simulations of the thermal evolution of Sylvia show that for a body of such a size, partial melting was unavoidable due to the decay of long-lived radionuclides. In addit

Published
2021

19. (216) Kleopatra, a low density critically rotating M-type asteroid

Author

Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Marchis, Franck, Jorda, Laurent, Vernazza, Pierre, Brož, Miroslav, Hanuš, Josef, Ferrais, Marin, Vachier, Frédéric, Rambaux, Nicolas, Marsset, Michaël, Viikinkoski, Matti, Jehin, Emmanuel, Benseguane, Selma, Podlewska-Gaca, Edyta, Carry, Benoît, Drouard, Alexis, Fauvaud, S., Birlan, Mirel, Berthier, Jérôme, Bartczak, Przemyslaw, Dumas, Christophe, Dudziński, Grzegorz, Ďurech, Josef, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Fétick, Romain, Fusco, Thierry, Grice, Jonny, Kryszczynska, Agnieszka, Lamy, Philippe, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Pajuelo, Myriam, Santana-Ros, Toni, Tanga, Paolo, Vigan, Arthur, Witasse, Olivier, Yang, Bin, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Marchis, Franck, Jorda, Laurent, Vernazza, Pierre, Brož, Miroslav, Hanuš, Josef, Ferrais, Marin, Vachier, Frédéric, Rambaux, Nicolas, Marsset, Michaël, Viikinkoski, Matti, Jehin, Emmanuel, Benseguane, Selma, Podlewska-Gaca, Edyta, Carry, Benoît, Drouard, Alexis, Fauvaud, S., Birlan, Mirel, Berthier, Jérôme, Bartczak, Przemyslaw, Dumas, Christophe, Dudziński, Grzegorz, Ďurech, Josef, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Fétick, Romain, Fusco, Thierry, Grice, Jonny, Kryszczynska, Agnieszka, Lamy, Philippe, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Pajuelo, Myriam, Santana-Ros, Toni, Tanga, Paolo, Vigan, Arthur, Witasse, Olivier, and Yang, Bin

Abstract

Context. The recent estimates of the 3D shape of the M/Xe-type triple asteroid system (216) Kleopatra indicated a density of ~5 g cm−3, which is by far the highest for a small Solar System body. Such a high density implies a high metal content as well as a low porosity which is not easy to reconcile with its peculiar “dumbbell” shape. Aims. Given the unprecedented angular resolution of the VLT/SPHERE/ZIMPOL camera, here, we aim to constrain the mass (via the characterization of the orbits of the moons) and the shape of (216) Kleopatra with high accuracy, hence its density. Methods. We combined our new VLT/SPHERE observations of (216) Kleopatra recorded during two apparitions in 2017 and 2018 with archival data from the W. M. Keck Observatory, as well as lightcurve, occultation, and delay-Doppler images, to derive a model of its 3D shape using two different algorithms (ADAM, MPCD). Furthermore, an N-body dynamical model allowed us to retrieve the orbital elements of the two moons as explained in the accompanying paper. Results. The shape of (216) Kleopatra is very close to an equilibrium dumbbell figure with two lobes and a thick neck. Its volume equivalent diameter (118.75 ± 1.40) km and mass (2.97 ± 0.32) × 1018 kg (i.e., 56% lower than previously reported) imply a bulk density of (3.38 ± 0.50) g cm−3. Such a low density for a supposedly metal-rich body indicates a substantial porosity within the primary. This porous structure along with its near equilibrium shape is compatible with a formation scenario including a giant impact followed by reaccumulation. (216) Kleopatra’s current rotation period and dumbbell shape imply that it is in a critically rotating state. The low effective gravity along the equator of the body, together with the equatorial orbits of the moons and possibly rubble-pile structure, opens the possibility that the moons formed via mass shedding. Conclusions. (216) Kleopatra is a puzzling multiple system due to the unique characteristics of the pr

Published
2021

20. FRIPON: a worldwide network to track incoming meteoroids

Author

Marsset, Michaël, Brož, Miroslav, Castillo-Rogez, Julie, Hanuš, Josef, Viikinkoski, Matti, Ševeček, Pavel, Marchis, Franck, Podlewska-Gaca, Edyta, Asphaug, Erik, Bartczak, Przemyslaw, Berthier, Jérôme, Cipriani, Fabrice, Dudziński, Grzegorz, Dumas, Christophe, Ďurech, Josef, Ferrais, Marin, Fétick, Romain, Fusco, Thierry, Kaasalainen, Mikko, Kryszczynska, Agnieszka, Lamy, Philippe, Le Coroller, Hervé, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Richardson, Derek, Santana-Ros, Toni, Vachier, Frédéric, Vigan, Arthur, Witasse, Olivier, Yang, Bin, Colas, François, Zanda, B., Bouley, S., Jeanne, S., Malgoyre, A., Birlan, Mirel, Blanpain, C., Gattacceca, J., Jorda, Laurent, Lecubin, J., Marmo, C., Rault, J., Vaubaillon, J., Vernazza, Pierre, Yohia, C., Gardiol, D., Nedelcu, A., Poppe, B., Rowe, J., Forcier, M., Trigo-Rodriguez, J., Lamy, H., Behrend, R., Ferrière, L., Barghini, D., Buzzoni, A., Carbognani, A., Di Carlo, M., Di Martino, M., Knapic, C., Londero, E., Pratesi, G., Rasetti, S., Riva, W., Stirpe, G., Valsecchi, G., Volpicelli, C., Zorba, S., Coward, D., Drolshagen, E., Drolshagen, G., Hernandez, O., Jehin, Emmanuel, Jobin, M., King, A., Nitschelm, C., Ott, T., Sanchez-Lavega, A., Toni, A., Abraham, P., Affaticati, F., Albani, M., Andreis, A., Andrieu, T., Anghel, S., Antaluca, E., Antier, K., Appéré, T., Armand, A., Ascione, G., Audureau, Y., Auxepaules, G., Avoscan, T., Baba Aissa, D., Bacci, P., Bǎdescu, O., Baldini, R., Baldo, R., Balestrero, A., Baratoux, D., Barbotin, E., Bardy, M., Basso, S., Bautista, O., Bayle, L., Beck, P., Bellitto, R., Belluso, R., Benna, C., Benammi, M., Beneteau, E., Benkhaldoun, Z., Bergamini, P., Bernardi, F., Bertaina, M., Bessin, P., Betti, L., Bettonvil, F., Bihel, D., Birnbaum, C., Blagoi, O., Blouri, E., Boacă, I., Boatǎ, R., Bobiet, B., Bonino, R., Boros, K., Bouchet, E., Borgeot, V., Bouchez, E., Boust, D., Boudon, V., Bouman, T., Bourget, P., Brandenburg, S., Bramond, Ph., Braun, E., Bussi, A., Cacault, P., Caillier, B., Calegaro, A., Camargo, J., Caminade, S., Campana, A., Campbell-Burns, P., Canal-Domingo, R., Carell, O., Carreau, S., Cascone, E., Cattaneo, C., Cauhape, P., Cavier, P., Celestin, S., Cellino, A., Champenois, M., Chennaoui Aoudjehane, H., Chevrier, S., Cholvy, P., Chomier, L., Christou, A., Cricchio, D., Coadou, P., Cocaign, J., Cochard, F., Cointin, S., Colombi, E., Colque Saavedra, J., Corp, L., Costa, M., Costard, F., COTTIER, M., Cournoyer, P., Coustal, E., Cremonese, G., Cristea, O., Cuzon, J., D’Agostino, G., Daiffallah, K., Dǎnescu, C., Dardon, A., Dasse, T., Davadan, C., Debs, V., Defaix, J., Deleflie, F., D’Elia, M., De Luca, P., De Maria, P., Deverchère, P., Devillepoix, H., Dias, A., Di Dato, A., Di Luca, R., Dominici, F., Drouard, Alexis, Dumont, J., Dupouy, P., Duvignac, L., Egal, A., Erasmus, N., Esseiva, N., Ebel, A., Eisengarten, B., Federici, F., Feral, S., Ferrant, G., Ferreol, E., Finitzer, P., Foucault, A., Francois, P., Frîncu, M., Froger, J., Gaborit, F., Gagliarducci, V., Galard, J., Gardavot, A., Garmier, M., Garnung, M., Gautier, B., Gendre, B., Gerard, D., Gerardi, A., Godet, J., Grandchamps, A., Grouiez, B., Groult, S., Guidetti, D., Giuli, G., Hello, Y., Henry, X., Herbreteau, G., Herpin, M., Hewins, P., Hillairet, J., Horak, J., Hueso, R., Huet, E., Huet, S., Hyaumé, F., Interrante, G., Isselin, Y., Jeangeorges, Y., Janeux, P., Jeanneret, P., Jobse, K., Jouin, S., Jouvard, J., Joy, K., Julien, J., Kacerek, R., Kaire, M., Kempf, M., Koschny, D., Krier, C., Kwon, M., Lacassagne, L., Lachat, D., Lagain, A., Laisné, E., Lanchares, V., Laskar, J., Lazzarin, M., Leblanc, M., Lebreton, J., Lecomte, J., Le Dû, P., LELONG, F., Lera, S., Leoni, J., Le-Pichon, A., Le-Poupon, P., Leroy, A., Leto, G., Levansuu, A., Lewin, E., Lienard, A., Licchelli, D., LOCATELLI, H., Loehle, S., Loizeau, D., Luciani, L., Maignan, M., Manca, F., Mancuso, S., Mandon, E., Mangold, N., Mannucci, F., Maquet, L., Marant, D., Marchal, Y., Marin, J., Martin-Brisset, J., Martin, D., Mathieu, D., Maury, A., Mespoulet, N., Meyer, F., Meyer, J., Meza, E., Moggi Cecchi, V., Moiroud, J., Millan, M., Montesarchio, M., Misiano, A., Molinari, E., Molau, S., Monari, J., Monflier, B., Monkos, A., Montemaggi, M., Monti, G., Moreau, R., Morin, J., Mourgues, R., Mousis, O., Nablanc, C., Nastasi, A., Niacşu, L., Notez, P., Ory, M., Pace, E., Paganelli, M., Pagola, A., Pajuelo, M., Palacián, J., Pallier, G., Paraschiv, P., Pardini, R., Pavone, M., Pavy, G., Payen, G., Pegoraro, A., Peña-Asensio, E., Perez, L., Pérez-Hoyos, S., Perlerin, V., Peyrot, A., Peth, F., Pic, V., Pietronave, S., Pilger, C., Piquel, M., Pisanu, T., Poppe, M., Portois, L., Prezeau, J., Pugno, N., Quantin, C., Quitté, G., Rambaux, Nicolas, Ravier, E., Repetti, U., Ribas, S., Richard, C., Richard, D., RIGONI, M., Rivet, J., Rizzi, N., Rochain, S., Rojas, J.F., Romeo, M., Rotaru, M., Rotger, M., Rougier, P., Rousselot, P., Rousset, J., Rousseu, D., Rubiera, O., Rudawska, R., Rudelle, J., Ruguet, J.P., Russo, P., Sales, S., Sauzereau, O., Salvati, F., Schieffer, M., Schreiner, D., Scribano, Y., Selvestrel, D., Serra, R., Shengold, L., Shuttleworth, A., Smareglia, R., Sohy, S., Soldi, M., Stanga, R., Steinhausser, A., Strafella, F., Sylla Mbaye, S., Smedley, A., Tagger, M., Tanga, Paolo, Taricco, C., Teng, J., Tercu, J., Thizy, O., Thomas, J., Tombelli, M., Trangosi, R., Tregon, B., Trivero, P., Tukkers, A., Turcu, V., Umbriaco, G., Unda-Sanzana, E., Vairetti, R., Valenzuela, M., Valente, G., Varennes, G., Vauclair, S., Vergne, J., Verlinden, M., Vidal-Alaiz, M., Vieira-Martins, R., Viel, A., Vîntdevarǎ, D., Vinogradoff, V., Volpini, P., Wendling, M., Wilhelm, P., Wohlgemuth, K., Yanguas, P., Zagarella, R., Zollo, A., l'Observatoire de Paris, Muséum national d'Histoire naturelle (France), Université Paris-Saclay, OSU Institut Pythéas, Istituto Nazionale di Astrofisica, Fondazione Cassa di Risparmio di Torino, Fondazione De Mari Savona, Diputación Foral de Bizkaia, Ministry of Research and Innovation (Romania), Museu de Astronomia e Ciências Afins (Brazil), Labex ESEP, Sorbonne Université, Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa. InaMat - Institute for Advanced Materials, Universidad Pública de Navarra. Departamento de Estadística, Informática y Matemáticas, Nafarroako Unibertsitate Publikoa. Estatistika, Informatika eta Matematika Saila, 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), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), 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), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Laboratoire de paléontologie, évolution, paléoécosystèmes, paléoprimatologie (PALEVOPRIM ), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL), Diagnostic des Plasmas Hors Equilibres (DPHE), Institut national universitaire Champollion [Albi] (INUC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Architecture et Logiciels pour Systèmes Embarqués sur Puce (ALSOC), LIP6, Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), 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), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géosciences - Le Mans (LPG - Le Mans), Laboratoire de Planétologie et Géosciences [UMR_C 6112] (LPG), Université d'Angers (UA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Université d'Angers (UA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Université de Technologie de Belfort-Montbeliard (UTBM)-Université de Bourgogne (UB)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT), Lumière, nanomatériaux et nanotechnologies (L2n), Institut Charles Delaunay (ICD), Université de Technologie de Troyes (UTT)-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Troyes (UTT)-Centre National de la Recherche Scientifique (CNRS), 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), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Colas, F., Zanda, B., Bouley, S., Jeanne, S., Malgoyre, A., Birlan, M., Blanpain, C., Gattacceca, J., Jorda, L., Lecubin, J., Marmo, C., Rault, J. L., Vaubaillon, J., Vernazza, P., Yohia, C., Gardiol, D., Nedelcu, A., Poppe, B., Rowe, J., Forcier, M., Koschny, D., Trigo-Rodriguez, J. M., Lamy, H., Behrend, R., Ferriere, L., Barghini, D., Buzzoni, A., Carbognani, A., Di Carlo, M., Di Martino, M., Knapic, C., Londero, E., Pratesi, G., Rasetti, S., Riva, W., Stirpe, G. M., Valsecchi, G. B., Volpicelli, C. A., Zorba, S., Coward, D., Drolshagen, E., Drolshagen, G., Hernandez, O., Jehin, E., Jobin, M., King, A., Nitschelm, C., Ott, T., Sanchez-Lavega, A., Toni, A., Abraham, P., Affaticati, F., Albani, M., Andreis, A., Andrieu, T., Anghel, S., Antaluca, E., Antier, K., Appere, T., Armand, A., Ascione, G., Audureau, Y., Auxepaules, G., Avoscan, T., Baba Aissa, D., Bacci, P., Badescu, O., Baldini, R., Baldo, R., Balestrero, A., Baratoux, D., Barbotin, E., Bardy, M., Basso, S., Bautista, O., Bayle, L. D., Beck, P., Bellitto, R., Belluso, R., Benna, C., Benammi, M., Beneteau, E., Benkhaldoun, Z., Bergamini, P., Bernardi, F., Bertaina, M. E., Bessin, P., Betti, L., Bettonvil, F., Bihel, D., Birnbaum, C., Blagoi, O., Blouri, E., Boaca, I., Boata, R., Bobiet, B., Bonino, R., Boros, K., Bouchet, E., Borgeot, V., Bouchez, E., Boust, D., Boudon, V., Bouman, T., Bourget, P., Brandenburg, S., Bramond, P., Braun, E., Bussi, A., Cacault, P., Caillier, B., Calegaro, A., Camargo, J., Caminade, S., Campana, A. P. C., Campbell-Burns, P., Canal-Domingo, R., Carell, O., Carreau, S., Cascone, E., Cattaneo, C., Cauhape, P., Cavier, P., Celestin, S., Cellino, A., Champenois, M., Chennaoui Aoudjehane, H., Chevrier, S., Cholvy, P., Chomier, L., Christou, A., Cricchio, D., Coadou, P., Cocaign, J. Y., Cochard, F., Cointin, S., Colombi, E., Colque Saavedra, J. P., Corp, L., Costa, M., Costard, F., Cottier, M., Cournoyer, P., Coustal, E., Cremonese, G., Cristea, O., Cuzon, J. C., D'Agostino, G., Daiffallah, K., Danescu, C., Dardon, A., Dasse, T., Davadan, C., Debs, V., Defaix, J. P., Deleflie, F., D'Elia, M., De Luca, P., De Maria, P., Deverchere, P., Devillepoix, H., Dias, A., Di Dato, A., Di Luca, R., Dominici, F. M., Drouard, A., Dumont, J. L., Dupouy, P., Duvignac, L., Egal, A., Erasmus, N., Esseiva, N., Ebel, A., Eisengarten, B., Federici, F., Feral, S., Ferrant, G., Ferreol, E., Finitzer, P., Foucault, A., Francois, P., Frincu, M., Froger, J. L., Gaborit, F., Gagliarducci, V., Galard, J., Gardavot, A., Garmier, M., Garnung, M., Gautier, B., Gendre, B., Gerard, D., Gerardi, A., Godet, J. P., Grandchamps, A., Grouiez, B., Groult, S., Guidetti, D., Giuli, G., Hello, Y., Henry, X., Herbreteau, G., Herpin, M., Hewins, P., Hillairet, J. J., Horak, J., Hueso, R., Huet, E., Huet, S., Hyaume, F., Interrante, G., Isselin, Y., Jeangeorges, Y., Janeux, P., Jeanneret, P., Jobse, K., Jouin, S., Jouvard, J. M., Joy, K., Julien, J. F., Kacerek, R., Kaire, M., Kempf, M., Krier, C., Kwon, M. K., Lacassagne, L., Lachat, D., Lagain, A., Laisne, E., Lanchares, V., Laskar, J., Lazzarin, M., Leblanc, M., Lebreton, J. P., Lecomte, J., Le Du, P., Lelong, F., Lera, S., Leoni, J. F., Le-Pichon, A., Le-Poupon, P., Leroy, A., Leto, G., Levansuu, A., Lewin, E., Lienard, A., Licchelli, D., Locatelli, H., Loehle, S., Loizeau, D., Luciani, L., Maignan, M., Manca, F., Mancuso, S., Mandon, E., Mangold, N., Mannucci, F., Maquet, L., Marant, D., Marchal, Y., Marin, J. L., Martin-Brisset, J. C., Martin, D., Mathieu, D., Maury, A., Mespoulet, N., Meyer, F., Meyer, J. Y., Meza, E., Moggi Cecchi, V., Moiroud, J. J., Millan, M., Montesarchio, M., Misiano, A., Molinari, E., Molau, S., Monari, J., Monflier, B., Monkos, A., Montemaggi, M., Monti, G., Moreau, R., Morin, J., Mourgues, R., Mousis, O., Nablanc, C., Nastasi, A., Niacsu, L., Notez, P., Ory, M., Pace, E., Paganelli, M. A., Pagola, A., Pajuelo, M., Palacian, J. F., Pallier, G., Paraschiv, P., Pardini, R., Pavone, M., Pavy, G., Payen, G., Pegoraro, A., Pena-Asensio, E., Perez, L., Perez-Hoyos, S., Perlerin, V., Peyrot, A., Peth, F., Pic, V., Pietronave, S., Pilger, C., Piquel, M., Pisanu, T., Poppe, M., Portois, L., Prezeau, J. F., Pugno, N., Quantin, C., Quitte, G., Rambaux, N., Ravier, E., Repetti, U., Ribas, S., Richard, C., Richard, D., Rigoni, M., Rivet, J. P., Rizzi, N., Rochain, S., Rojas, J. F., Romeo, M., Rotaru, M., Rotger, M., Rougier, P., Rousselot, P., Rousset, J., Rousseu, D., Rubiera, O., Rudawska, R., Rudelle, J., Ruguet, J. P., Russo, P., Sales, S., Sauzereau, O., Salvati, F., Schieffer, M., Schreiner, D., Scribano, Y., Selvestrel, D., Serra, R., Shengold, L., Shuttleworth, A., Smareglia, R., Sohy, S., Soldi, M., Stanga, R., Steinhausser, A., Strafella, F., Sylla Mbaye, S., Smedley, A. R. D., Tagger, M., Tanga, P., Taricco, C., Teng, J. P., Tercu, J. O., Thizy, O., Thomas, J. P., Tombelli, M., Trangosi, R., Tregon, B., Trivero, P., Tukkers, A., Turcu, V., Umbriaco, G., Unda-Sanzana, E., Vairetti, R., Valenzuela, M., Valente, G., Varennes, G., Vauclair, S., Vergne, J., Verlinden, M., Vidal-Alaiz, M., Vieira-Martins, R., Viel, A., Vintdevara, D. C., Vinogradoff, V., Volpini, P., Wendling, M., Wilhelm, P., Wohlgemuth, K., Yanguas, P., Zagarella, R., Zollo, A., Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa. INAMAT2 - Institute for Advanced Materials and Mathematics, Ferrière, L., Appéré, T., Bǎdescu, O., Boacă, I., Boatǎ, R., Bramond, Ph., D’Agostino, G., Dǎnescu, C., D’Elia, M., Deverchère, P., Frîncu, M., Hyaumé, F., Laisné, E., Le Dû, P., Niacşu, L., Palacián, J. F., Peña-Asensio, E., Pérez-Hoyos, S., Quitté, G., Rojas, J.F., Ruguet, J.P., Vîntdevarǎ, D. C., Research unit Medical Physics, and Damage and Repair in Cancer Development and Cancer Treatment (DARE)

Subjects
DYNAMICS, [INFO.INFO-AR]Computer Science [cs]/Hardware Architecture [cs.AR], Meteors, Computer science, Radio receiver, [INFO.INFO-DM]Computer Science [cs]/Discrete Mathematics [cs.DM], Surveys, 010502 geochemistry & geophysics, Track (rail transport), 01 natural sciences, Meteorites, meteors, meteoroids, law.invention, Planets and planetary system, [INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing, Methods: observational, law, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], meteoroids, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Observational methods, Earth and Planetary Astrophysics (astro-ph.EP), meteoroids -surveys -methods: observational -interplanetary medium, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], ORIGIN, [INFO.INFO-AO]Computer Science [cs]/Computer Arithmetic, meteorites, meteors, meteoroids – surveys – methods: observational – interplanetary medium, Meteoroids, RECOVERY, ORBIT, Meteorite, Fully automated, Interplanetary medium, [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], Astrophysics - Instrumentation and Methods for Astrophysics, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, FLUX, Real-time computing, fripon, [INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS], FOS: Physical sciences, Context (language use), CAMERA, [INFO.INFO-SE]Computer Science [cs]/Software Engineering [cs.SE], [SPI.AUTO]Engineering Sciences [physics]/Automatic, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 0103 physical sciences, FIREBALL NETWORK, observational [Methods], meteors, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Meteoroid, INNISFREE METEORITE, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Astronomy and Astrophysics, METEORITE FALL, Meteorites, meteors, meteoroid, Camera network, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Interplanetary spaceflight, meteroids tracking, meteoroids - surveys - methods: observational, SYSTEM, Astrophysics - Earth and Planetary Astrophysics, Meteorites
Abstract

Context. Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile - hence precious - meteorites must be recovered rapidly to avoid their alteration. Aims. The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receivers and covers an area of about 1.5 × 10km. Methods. The FRIPON network, fully operational since 2018, has been monitoring meteoroid entries since 2016, thereby allowing the characterization of their dynamical and physical properties. In addition, the level of automation of the network makes it possible to trigger a meteorite recovery campaign only a few hours after it reaches the surface of the Earth. Recovery campaigns are only organized for meteorites with final masses estimated of at least 500 g, which is about one event per year in France. No recovery campaign is organized in the case of smaller final masses on the order of 50 to 100 g, which happens about three times a year; instead, the information is delivered to the local media so that it can reach the inhabitants living in the vicinity of the fall. Results. Nearly 4000 meteoroids have been detected so far and characterized by FRIPON. The distribution of their orbits appears to be bimodal, with a cometary population and a main belt population. Sporadic meteors amount to about 55% of all meteors. A first estimate of the absolute meteoroid flux (mag < -5; meteoroid size ≥∼1 cm) amounts to 1250/yr/10km. This value is compatible with previous estimates. Finally, the first meteorite was recovered in Italy (Cavezzo, January 2020) thanks to the PRISMA network, a component of the FRIPON science project., FRIPON was initiated by funding from ANR (grant N.13- BS05-0009-03), carried by the Paris Observatory, Muséum National d’Histoire Naturelle, Paris-Saclay University and Institut Pythéas (LAM-CEREGE). VigieCiel was part of the 65 Millions d’Observateurs project, carried by the Muséum National d’Histoire Naturelle and funded by the French Investissements d’Avenir program. FRIPON data are hosted and processed at Institut Pythéas SIP (Service Informatique Pythéas), and a mirror is hosted at IMCCE (Institut de Mécanique Céleste et de Calcul des Éphémérides / Paris Observatory) with the help of IDOC (https://idoc.ias.u-psud.fr) (Integrated Data and Operation Center), supported by CNRS and CNES. PRISMA is the Italian Network for Systematic surveillance of Meteors and Atmosphere. It is a collaboration initiated and coordinated by the Italian National Institute for Astrophysics (INAF) that counts members among research institutes, associations and schools (http://www.prisma.inaf.it). PRISMA was partially funded by 2016 and 2020 Research and Education grants from Fondazione Cassa di Risparmio di Torino and by a 2016 grant from Fondazione Agostino De Mari (Savona). FRIPON-Bilbao is supported by a grant from Diputacion Foral Bizkaia (DFB/BFA). FRIPONMOROI was supported by a grant of the Romanian Ministery of Research and Innovation, CCCDI - UEFISCDI, project number PN-III-P1-1.2-PCCDI2017-0226/16PCCDI/2018 , within PNCDI III. Rio de Janeiro camera is hosted and partially maintained by MAST (Museum of Astronomy and Related Sciences)/MCTIC. The Meteorix project acknowledges supports from labex ESEP (Exploration Spatiale des Environnements Planétaires), DIM-ACAV+ Région Île-de-France, Janus CNES, IDEX Sorbonne Universités and Sorbonne Université.

Published
2020

21. Impact of ocean-atmosphere current feedback on the ocean mesoscale activity: regional variations, and sensitivity to model resolution

Author

Jullien, Swen, Masson, Sébastien, Oerder, Véra, Samson, Guillaume, Colas, François, Renault, Lionel, Jullien, Swen, Masson, Sébastien, Oerder, Véra, Samson, Guillaume, Colas, François, and Renault, Lionel

Abstract

Ocean mesoscale eddies are characterized by rotating-like and meandering currents that imprint the low-level atmosphere. Such a current feedback (CFB) has been shown to induce a sink of energy from the ocean to the atmosphere, and consequently to damp the eddy kinetic energy (EKE), with an apparent regional disparity. In a context of increasing model resolution, the importance of this feedback, and its dependence on oceanic and atmospheric models resolution arise. Using a hierarchy of quasi-global coupled models with spatial resolutions varying from ¼° to 1/12°, the present study shows that the CFB induces a negative wind work at scales ranging from 100 to 1000 km, and a subsequent damping of the mesoscale activity by ∼30% on average, independently of the model resolution. Regional variations of this damping range from ∼20% in very rich-eddying regions to ∼40% in poor-eddying regions. This regional modulation is associated to a different balance between the sink of energy by eddy wind work, and the source of EKE by ocean intrinsic instabilities. The efficiency of the CFB is also shown to be a function of the surface wind magnitude: the larger the wind, the larger the sink of energy. The CFB impact is thus related to both wind and EKE. Its correct representation requires both an ocean model that resolves the mesoscale field adequately, and an atmospheric model resolution that matches the ocean effective resolution and allows a realistic representation of wind patterns. These results are crucial for including adequately mesoscale ocean-atmosphere interactions in coupled general circulation models, and have strong implications in climate research.

Published
2020
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22. Volume uncertainty of (7) Iris shape models from disc-resolved images

Author

Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Dudziński, Grzegorz, Podlewska-Gaca, Edyta, Bartczak, Przemyslaw, Benseguane, Selma, Ferrais, Marin, Jorda, Laurent, Hanuš, Josef, Vernazza, Pierre, Rambaux, Nicolas, Carry, Benoît, Marchis, Franck, Marsset, Michaël, Viikinkoski, Matti, Brož, Miroslav, Fetick, Romain, Drouard, Alexis, Fusco, Thierry, Birlan, Mirel, Jehin, Emmanuel, Berthier, Jérôme, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Dumas, Christophe, Kryszczynska, Agnieszka, Lamy, Philippe, Le Coroller, Hervé, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Santana-Ros, Toni, Tanga, Paolo, Vachier, Frédéric, Vigan, Arthur, Witasse, Olivier, Yang, Bin, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Dudziński, Grzegorz, Podlewska-Gaca, Edyta, Bartczak, Przemyslaw, Benseguane, Selma, Ferrais, Marin, Jorda, Laurent, Hanuš, Josef, Vernazza, Pierre, Rambaux, Nicolas, Carry, Benoît, Marchis, Franck, Marsset, Michaël, Viikinkoski, Matti, Brož, Miroslav, Fetick, Romain, Drouard, Alexis, Fusco, Thierry, Birlan, Mirel, Jehin, Emmanuel, Berthier, Jérôme, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Dumas, Christophe, Kryszczynska, Agnieszka, Lamy, Philippe, Le Coroller, Hervé, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Santana-Ros, Toni, Tanga, Paolo, Vachier, Frédéric, Vigan, Arthur, Witasse, Olivier, and Yang, Bin

Abstract

High angular resolution disc-resolved images of (7) Iris collected by VLT/SPHERE instrument are allowed for the detailed shape modelling of this large asteroid revealing its surface features. If (7) Iris did not suffer any events catastrophic enough to disrupt the body (which is very likely) by studying its topography, we might get insights into the early Solar system’s collisional history. When it comes to internal structure and composition, thoroughly assessing the volume and density uncertainties is necessary. In this work, we propose a method of uncertainty calculation of asteroid shape models based on light curve and adaptive optics (AO) images. We apply this method on four models of (7) Iris produced from independent Shaping Asteroids using Genetic Evolution and All-Data Asteroid Modelling inversion techniques and multiresolution photoclinometry by deformation. Obtained diameter uncertainties stem from both the observations from which the models were scaled and the models themselves. We show that despite the availability of high-resolution AO images, the volume and density of (7) Iris have substantial error bars that were underestimated in the previous studies.

Published
2020

23. The large trans-Neptunian object 2002 TC302 from combined stellar occultation, photometry, and astrometry data

Author

Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante. Instituto Universitario de Investigación Informática, Ortiz Moreno, José Luis, Santos Sanz, Pablo, Sicardy, B., Benedetti-Rossi, G., Duffard, René, Morales Palomino, Nicolás, Braga-Ribas, F., Fernández-Valenzuela, Estela, Nascimbeni, V., Nardiello, D., Carbognani, A., Buzzi, Luca, Aletti, A., Bacci, P., Maestripieri, M., Mazzei, L., Mikuz, H., Skvarc, J., Ciabattari, F., Lavalade, F., Scarfi, G., Mari, J.M., Conjat, M., Sposetti, S., Bachini, M., Succi, G., Mancini, F., Alighieri, M., Dal Canto, E., Masucci, M., Vara-Lubiano, M., Gutiérrez, P.J., Desmars, Josselin, Lecacheux, J., Vieira-Martins, R., Camargo, J.I.B., Assafin, M., Colas, François, Beisker, W., Behrend, Raoul, Mueller, T.G., Meza, E., Gomes-Junior, A.R., Roques, F., Vachier, Frédéric, Mottola, S., Hellmich, S., Campo Bagatin, Adriano, Alvarez-Candal, Alvaro, Cikota, S., Cikota, A., Christille, J.M., Pál, András, Kiss, C., Pribulla, T., Komžík, R., Madiedo, J.M., Charmandaris, V., Alikakos, J., Szakáts, Róbert, Farkas, Anikó, Varga-Verebélyi, E., Marton, G., Marciniak, Anna, Bartczak, Przemyslaw, Butkiewicz-Bąk, Magdalena, Dudziński, Grzegorz, Alí-Lagoa, Víctor, Gazeas, K., Paschalis, N., Tsamis, V., Guirado, J.C., Peris, V., Iglesias-Marzoa, R., Schnabel, C., Manzano, F., Navarro, A., Perelló, C., Vecchione, A., Noschese, A., Morrone, L., Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante. Instituto Universitario de Investigación Informática, Ortiz Moreno, José Luis, Santos Sanz, Pablo, Sicardy, B., Benedetti-Rossi, G., Duffard, René, Morales Palomino, Nicolás, Braga-Ribas, F., Fernández-Valenzuela, Estela, Nascimbeni, V., Nardiello, D., Carbognani, A., Buzzi, Luca, Aletti, A., Bacci, P., Maestripieri, M., Mazzei, L., Mikuz, H., Skvarc, J., Ciabattari, F., Lavalade, F., Scarfi, G., Mari, J.M., Conjat, M., Sposetti, S., Bachini, M., Succi, G., Mancini, F., Alighieri, M., Dal Canto, E., Masucci, M., Vara-Lubiano, M., Gutiérrez, P.J., Desmars, Josselin, Lecacheux, J., Vieira-Martins, R., Camargo, J.I.B., Assafin, M., Colas, François, Beisker, W., Behrend, Raoul, Mueller, T.G., Meza, E., Gomes-Junior, A.R., Roques, F., Vachier, Frédéric, Mottola, S., Hellmich, S., Campo Bagatin, Adriano, Alvarez-Candal, Alvaro, Cikota, S., Cikota, A., Christille, J.M., Pál, András, Kiss, C., Pribulla, T., Komžík, R., Madiedo, J.M., Charmandaris, V., Alikakos, J., Szakáts, Róbert, Farkas, Anikó, Varga-Verebélyi, E., Marton, G., Marciniak, Anna, Bartczak, Przemyslaw, Butkiewicz-Bąk, Magdalena, Dudziński, Grzegorz, Alí-Lagoa, Víctor, Gazeas, K., Paschalis, N., Tsamis, V., Guirado, J.C., Peris, V., Iglesias-Marzoa, R., Schnabel, C., Manzano, F., Navarro, A., Perelló, C., Vecchione, A., Noschese, A., and Morrone, L.

Abstract

Context. Deriving physical properties of trans-Neptunian objects is important for the understanding of our Solar System. This requires observational efforts and the development of techniques suitable for these studies. Aims. Our aim is to characterize the large trans-Neptunian object (TNO) 2002 TC302. Methods. Stellar occultations offer unique opportunities to determine key physical properties of TNOs. On 28 January 2018, 2002 TC302 occulted a mv ~ 15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia, and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto in terms of the number of chords published thus far. From the 12 chords, an accurate elliptical fit to the instantaneous projection of the body can be obtained that is compatible with the near misses. Results. The resulting ellipse has major and minor axes of 543 ± 18 km and 460 ± 11 km, respectively, with a position angle of 3 ± 1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5 m telescope at Sierra Nevada Observatory and the 1.23 m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84 km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ~300 km in diameter, which is required to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also a

Published
2020

24. Asteroid (16) Psyche’s primordial shape: A possible Jacobi ellipsoid

Author

Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Ferrais, Marin, Vernazza, Pierre, Jorda, Laurent, Rambaux, Nicolas, Hanuš, Josef, Carry, Benoît, Marchis, Franck, Marsset, Michaël, Viikinkoski, Matti, Brož, Miroslav, Fetick, Romain, Drouard, Alexis, Fusco, Thierry, Birlan, Mirel, Podlewska-Gaca, Edyta, Jehin, Emmanuel, Bartczak, Przemyslaw, Berthier, Jérôme, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Dudziński, Grzegorz, Dumas, Christophe, Ďurech, Josef, Kaasalainen, Mikko, Kryszczynska, Agnieszka, Lamy, Philippe, Le Coroller, Hervé, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Santana-Ros, Toni, Tanga, Paolo, Vachier, Frédéric, Vigan, Arthur, Witasse, Olivier, Yang, Bin, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Ferrais, Marin, Vernazza, Pierre, Jorda, Laurent, Rambaux, Nicolas, Hanuš, Josef, Carry, Benoît, Marchis, Franck, Marsset, Michaël, Viikinkoski, Matti, Brož, Miroslav, Fetick, Romain, Drouard, Alexis, Fusco, Thierry, Birlan, Mirel, Podlewska-Gaca, Edyta, Jehin, Emmanuel, Bartczak, Przemyslaw, Berthier, Jérôme, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Dudziński, Grzegorz, Dumas, Christophe, Ďurech, Josef, Kaasalainen, Mikko, Kryszczynska, Agnieszka, Lamy, Philippe, Le Coroller, Hervé, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Santana-Ros, Toni, Tanga, Paolo, Vachier, Frédéric, Vigan, Arthur, Witasse, Olivier, and Yang, Bin

Abstract

Context. Asteroid (16) Psyche is the largest M-type asteroid in the main belt and the target of the NASA Psyche mission. It is also the only asteroid of this size (D > 200 km) known to be metal rich. Although various hypotheses have been proposed to explain the rather unique physical properties of this asteroid, a perfect understanding of its formation and bulk composition is still missing. Aims. We aim to refine the shape and bulk density of (16) Psyche and to perform a thorough analysis of its shape to better constrain possible formation scenarios and the structure of its interior. Methods. We obtained disk-resolved VLT/SPHERE/ZIMPOL images acquired within our ESO large program (ID 199.C-0074), which complement similar data obtained in 2018. Both data sets offer a complete coverage of Psyche’s surface. These images were used to reconstruct the three-dimensional (3D) shape of Psyche with two independent shape modeling algorithms (MPCD and ADAM). A shape analysis was subsequently performed, including a comparison with equilibrium figures and the identification of mass deficit regions. Results. Our 3D shape along with existing mass estimates imply a density of 4.20 ± 0.60 g cm−3, which is so far the highest for a solar system object following the four telluric planets. Furthermore, the shape of Psyche presents small deviations from an ellipsoid, that is, prominently three large depressions along its equator. The flatness and density of Psyche are compatible with a formation at hydrostatic equilibrium as a Jacobi ellipsoid with a shorter rotation period of ∼3h. Later impacts may have slowed down Psyche’s rotation, which is currently ∼4.2 h, while also creating the imaged depressions. Conclusions. Our results open the possibility that Psyche acquired its primordial shape either after a giant impact while its interior was already frozen or while its interior was still molten owing to the decay of the short-lived radionuclide 26Al.

Published
2020

25. Binary asteroid (31) Euphrosyne: ice-rich and nearly spherical

Author

Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Yang, Bin, Hanuš, Josef, Carry, Benoît, Vernazza, Pierre, Brož, Miroslav, Vachier, Frédéric, Rambaux, Nicolas, Marsset, Michaël, Chrenko, Ondrej, Ševeček, Pavel, Viikinkoski, Matti, Jehin, Emmanuel, Ferrais, Marin, Podlewska-Gaca, Edyta, Drouard, Alexis, Marchis, Franck, Birlan, Mirel, Benkhaldoun, Zouhair, Berthier, Jérôme, Bartczak, Przemyslaw, Dumas, Christophe, Dudziński, Grzegorz, Ďurech, Josef, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Fétick, Romain, Fusco, Thierry, Grice, Jonny, Jorda, Laurent, Kaasalainen, Mikko, Kryszczynska, Agnieszka, Lamy, Philippe, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Pajuelo, Myriam, Santana-Ros, Toni, Tanga, Paolo, Vigan, Arthur, Witasse, Olivier, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Yang, Bin, Hanuš, Josef, Carry, Benoît, Vernazza, Pierre, Brož, Miroslav, Vachier, Frédéric, Rambaux, Nicolas, Marsset, Michaël, Chrenko, Ondrej, Ševeček, Pavel, Viikinkoski, Matti, Jehin, Emmanuel, Ferrais, Marin, Podlewska-Gaca, Edyta, Drouard, Alexis, Marchis, Franck, Birlan, Mirel, Benkhaldoun, Zouhair, Berthier, Jérôme, Bartczak, Przemyslaw, Dumas, Christophe, Dudziński, Grzegorz, Ďurech, Josef, Castillo-Rogez, Julie, Cipriani, Fabrice, Colas, François, Fétick, Romain, Fusco, Thierry, Grice, Jonny, Jorda, Laurent, Kaasalainen, Mikko, Kryszczynska, Agnieszka, Lamy, Philippe, Marciniak, Anna, Michalowski, Tadeusz, Michel, Patrick, Pajuelo, Myriam, Santana-Ros, Toni, Tanga, Paolo, Vigan, Arthur, and Witasse, Olivier

Abstract

Aims. Asteroid (31) Euphrosyne is one of the biggest objects in the asteroid main belt and it is also the largest member of its namesake family. The Euphrosyne family occupies a highly inclined region in the outer main belt and contains a remarkably large number of members, which is interpreted as an outcome of a disruptive cratering event. Methods. The goals of this adaptive-optics imaging study are threefold: to characterize the shape of Euphrosyne, to constrain its density, and to search for the large craters that may be associated with the family formation event. Results. We obtained disk-resolved images of Euphrosyne using SPHERE/ZIMPOL at the ESO 8.2 m VLT as part of our large program (ID: 199.C-0074, PI: Vernazza). We reconstructed its 3D shape via the ADAM shape modeling algorithm based on the SPHERE images and the available light curves of this asteroid. We analyzed the dynamics of the satellite with the Genoid meta-heuristic algorithm. Finally, we studied the shape of Euphrosyne using hydrostatic equilibrium models. Conclusions. Our SPHERE observations show that Euphrosyne has a nearly spherical shape with the sphericity index of 0.9888 and its surface lacks large impact craters. Euphrosyne’s diameter is 268 ± 6 km, making it one of the top ten largest main belt asteroids. We detected a satellite of Euphrosyne – S/2019 (31) 1 – that is about 4 km across, on a circular orbit. The mass determined from the orbit of the satellite together with the volume computed from the shape model imply a density of 1665 ± 242 kg m−3, suggesting that Euphrosyne probably contains a large fraction of water ice in its interior. We find that the spherical shape of Euphrosyne is a result of the reaccumulation process following the impact, as in the case of (10) Hygiea. However, our shape analysis reveals that, contrary to Hygiea, the axis ratios of Euphrosyne significantly differ from those suggested by fluid hydrostatic equilibrium following reaccumulation.

Published
2020

26. Volume uncertainty of (7) Iris shape models from disc-resolved images

Author

Czech Science Foundation, European Commission, Dudziński, G., Podlewska-Gaca, E., Bartczak, P., Benseguane, S., Ferrais, M., Jorda, Laurent, Hanuš, J., Vernazza, Pierre, Rambaux, N., Carry, B., Marchis, F., Marsset, M., Viikinkoski, M., Brož, M., Fetick, R., Drouard, A., Fusco, Thierry, Birlan, M., Jehin, Emmanuël, Berthier, J., Castillo-Rogez, J., Cipriani, Fabrice, Colas, François, Dumas, C., Kryszczynska, A., Lamy, P., Le Coroller, H., Marciniak, A., Michalowski, T., Michel, P., Santana-Ros, Toni, Tanga, P., Vachier, F., Vigan, A., Witasse, O., Yang, B., Czech Science Foundation, European Commission, Dudziński, G., Podlewska-Gaca, E., Bartczak, P., Benseguane, S., Ferrais, M., Jorda, Laurent, Hanuš, J., Vernazza, Pierre, Rambaux, N., Carry, B., Marchis, F., Marsset, M., Viikinkoski, M., Brož, M., Fetick, R., Drouard, A., Fusco, Thierry, Birlan, M., Jehin, Emmanuël, Berthier, J., Castillo-Rogez, J., Cipriani, Fabrice, Colas, François, Dumas, C., Kryszczynska, A., Lamy, P., Le Coroller, H., Marciniak, A., Michalowski, T., Michel, P., Santana-Ros, Toni, Tanga, P., Vachier, F., Vigan, A., Witasse, O., and Yang, B.

Abstract

High angular resolution disc-resolved images of (7) Iris collected by VLT/SPHERE instrument are allowed for the detailed shape modelling of this large asteroid revealing its surface features. If (7) Iris did not suffer any events catastrophic enough to disrupt the body (which is very likely) by studying its topography, we might get insights into the early Solar system’s collisional history. When it comes to internal structure and composition, thoroughly assessing the volume and density uncertainties is necessary. In this work, we propose a method of uncertainty calculation of asteroid shape models based on light curve and adaptive optics (AO) images. We apply this method on four models of (7) Iris produced from independent Shaping Asteroids using Genetic Evolution and All-Data Asteroid Modelling inversion techniques and multiresolution photoclinometry by deformation. Obtained diameter uncertainties stem from both the observations from which the models were scaled and the models themselves. We show that despite the availability of high-resolution AO images, the volume and density of (7) Iris have substantial error bars that were underestimated in the previous studies.

Published
2020

27. FRIPON: A worldwide network to track incoming meteoroids

Author

l'Observatoire de Paris, Muséum national d'Histoire naturelle (France), Université Paris-Saclay, OSU Institut Pythéas, Istituto Nazionale di Astrofisica, Fondazione Cassa di Risparmio di Torino, Fondazione De Mari Savona, Diputación Foral de Bizkaia, Ministry of Research and Innovation (Romania), Museu de Astronomia e Ciências Afins (Brazil), Labex ESEP, Sorbonne Université, Colas, François, Trigo-Rodríguez, Josep María, Peña-Asensio, Eloy, Zollo, A., FRIPON, l'Observatoire de Paris, Muséum national d'Histoire naturelle (France), Université Paris-Saclay, OSU Institut Pythéas, Istituto Nazionale di Astrofisica, Fondazione Cassa di Risparmio di Torino, Fondazione De Mari Savona, Diputación Foral de Bizkaia, Ministry of Research and Innovation (Romania), Museu de Astronomia e Ciências Afins (Brazil), Labex ESEP, Sorbonne Université, Colas, François, Trigo-Rodríguez, Josep María, Peña-Asensio, Eloy, Zollo, A., and FRIPON

Abstract

Context. Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile - hence precious - meteorites must be recovered rapidly to avoid their alteration. Aims. The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receivers and covers an area of about 1.5 × 10km. Methods. The FRIPON network, fully operational since 2018, has been monitoring meteoroid entries since 2016, thereby allowing the characterization of their dynamical and physical properties. In addition, the level of automation of the network makes it possible to trigger a meteorite recovery campaign only a few hours after it reaches the surface of the Earth. Recovery campaigns are only organized for meteorites with final masses estimated of at least 500 g, which is about one event per year in France. No recovery campaign is organized in the case of smaller final masses on the order of 50 to 100 g, which happens about three times a year; instead, the information is delivered to the local media so that it can reach the inhabitants living in the vicinity of the fall. Results. Nearly 4000 meteoroids have been detected so far and characterized by FRIPON. The distribution of their orbits appears to be bimodal, with a cometary population and a main belt population. Sporadic meteors amount to about 55% of all meteors. A first estimate of the absolute meteoroid flux (mag < -5; meteoroid size ≥∼1 cm) amounts to 1250/yr/10km. This value is compatible with previous estimates. Finally, the first meteorite was recovered in Italy (Cavezzo, January 2020)

Published
2020

28. Asteroid (16) Psyche's primordial shape: A possible Jacobi ellipsoid

Author

European Southern Observatory, Centre National de la Recherche Scientifique (France), Czech Science Foundation, Charles University (Czech Republic), Generalitat Valenciana, European Commission, Ministerio de Economía y Competitividad (España), Ferrais, M., Vernazza, Pierre, Jorda, Laurent, Rambaux, N., Hanuš, J., Carry, B., Marchis, F., Marsset, M., Viikinkoski, M., Brož, M., Fetick, R., Drouard, A., Fusco, Thierry, Birlan, M., Podlewska-Gaca, E., Jehin, Emmanuël, Bartczak, P., Castillo-Rogez, J., Cipriani, Fabrice, Colas, François, Dudziński, G., Dumas, C., Ğ Urech, J., Kaasalainen, Mikko, Kryszczynska, A., Lamy, P., Le Coroller, H., Marciniak, A., Michalowski, T., Michel, P., Santana-Ros, Toni, Tanga, P., Vachier, F., Vigan, A., Witasse, O., Yang, B., European Southern Observatory, Centre National de la Recherche Scientifique (France), Czech Science Foundation, Charles University (Czech Republic), Generalitat Valenciana, European Commission, Ministerio de Economía y Competitividad (España), Ferrais, M., Vernazza, Pierre, Jorda, Laurent, Rambaux, N., Hanuš, J., Carry, B., Marchis, F., Marsset, M., Viikinkoski, M., Brož, M., Fetick, R., Drouard, A., Fusco, Thierry, Birlan, M., Podlewska-Gaca, E., Jehin, Emmanuël, Bartczak, P., Castillo-Rogez, J., Cipriani, Fabrice, Colas, François, Dudziński, G., Dumas, C., Ğ Urech, J., Kaasalainen, Mikko, Kryszczynska, A., Lamy, P., Le Coroller, H., Marciniak, A., Michalowski, T., Michel, P., Santana-Ros, Toni, Tanga, P., Vachier, F., Vigan, A., Witasse, O., and Yang, B.

Abstract

Context. Asteroid (16) Psyche is the largest M-type asteroid in the main belt and the target of the NASA Psyche mission. It is also the only asteroid of this size (D> 200 km) known to be metal rich. Although various hypotheses have been proposed to explain the rather unique physical properties of this asteroid, a perfect understanding of its formation and bulk composition is still missing. Aims. We aim to refine the shape and bulk density of (16) Psyche and to perform a thorough analysis of its shape to better constrain possible formation scenarios and the structure of its interior. Methods. We obtained disk-resolved VLT/SPHERE/ZIMPOL images acquired within our ESO large program (ID 199.C-0074), which complement similar data obtained in 2018. Both data sets offer a complete coverage of Psyche's surface. These images were used to reconstruct the three-dimensional (3D) shape of Psyche with two independent shape modeling algorithms (MPCD and ADAM). A shape analysis was subsequently performed, including a comparison with equilibrium figures and the identification of mass deficit regions. Results. Our 3D shape along with existing mass estimates imply a density of 4.20 ± 0.60 g cm-3, which is so far the highest for a solar system object following the four telluric planets. Furthermore, the shape of Psyche presents small deviations from an ellipsoid, that is, prominently three large depressions along its equator. The flatness and density of Psyche are compatible with a formation at hydrostatic equilibrium as a Jacobi ellipsoid with a shorter rotation period of ∼3h. Later impacts may have slowed down Psyche's rotation, which is currently ∼4.2 h, while also creating the imaged depressions. Conclusions. Our results open the possibility that Psyche acquired its primordial shape either after a giant impact while its interior was already frozen or while its interior was still molten owing to the decay of the short-lived radionuclide 26Al.

Published
2020

29. Size and Shape Constraints of (486958) Arrokoth from Stellar Occultations

Author

European Research Council, European Commission, National Aeronautics and Space Administration (US), Centre National de la Recherche Scientifique (France), Ministerio de Ciencia, Innovación y Universidades (España), German Centre for Air and Space Travel, Department of Energy (US), National Science Foundation (US), Australian National University, Buie, Marc W., Porter, Simon B., Tamblyn, Peter, Terrell, Dirk, Parker, Alex Harrison, Baratoux, David, Kaire, Maram, Leiva, Rodrigo, Verbiscer, Anne J., Zangari, Amanda M., Colas, François, Tamayo, Francisco J., Throop, Henry B., Torres Cañas, Andrés David, Toure, Labaly, Traore, Alassane, Tsang, Constantine C. C., Turner, Jake D., Vanegas, Santiago, Venable, Roger, Wasserman, Lawrence H., Camino López, Matías Aarón, Wilson, John C., Zuluaga, Carlos A., Zuluaga, Jorge I., Benecchi, Susan D., Caspi, Amir, Gwyn, Stephen, Kavelaars, J. J., Ocampo Uría, Adriana C., Rabassa, Jorge, Skrutskie, M. F., Carter, Christian M., Soto, Alejandro, Tanga, Paolo, Young, Eliot F., Stern, S. Alan, Andersen, Bridget C., Arango Pérez, Mauricio E., Arredondo, Anicia, Artola, Rodolfo Alfredo, Bâ, Abdoulaye, Ballet, Romuald, Castro-Chacón, J. H., Blank, Ted, Bop, Cheikh Tidiane, Bosh, Amanda S., Caycedo Desprez, Alfonso, Caycedo Guerra, Nicolás, Conard, Steven J., Dauvergne, Jean-Luc, Dean, Bryan, Dean, Michelle, Desmars, Josselin, González Murillo, Giovanni Francisco, Dieng, Abdou Lahat, Bousso Dieng, Mame Diarra, Diouf, Omar, Dorego, Gualbert Séraphin, Dunham, David W., Dunham, Joan, Durantini Luca, Hugo A., Edwards, Patrick, Erasmus, Nicolas, Faye, Gayane, Grusin, Michael D., Faye, Mactar, Ferrario, Lucas Ezequiel, Ferrell, Chelsea L., Finley, Tiffany J., Fraser, Wesley C., Friedli, Alison J., Galvez Serna, Julián, Garcia-Migani, Esteban A., Genade, Anja, Getrost, Kai, Gurovich, Sebastian, Gil-Hutton, Ricardo A., Gimeno, German N., Golub, Eli Joseph, Hanna, William H., Henn, Santiago M., Hinton, P. C., Hughes, Paul J., Josephs, John David, Jr., Joya, Raul, Kammer, Joshua A., Pinzón, Giovanni, Keeney, Brian A., Keller, John M., Kramer, Emily A., Levine, Stephen E., Lisse, Carey M., Lovell, Amy J., Mackie, Jason A., Makarchuk, Stanislav, Manzano, Luis E., Mbaye, Salma Sylla, Pulver, Eduardo Alejandro, Mbaye, Modou, Melia, Raul Roberto, Moreno, Freddy, Moss, Sean K., Ndaiye, Diene, Ndiaye, Mapathe, Nelson, Matthew J., Olkin, Catherine B., Olsen, Aart M., Ospina Moreno, Victor Jonathan, Quintero, Edwin A., Pasachoff, Jay M., Pereyra, Mariana Belen, Person, Michael J., Regester, Jeffrey R., Resnick, Aaron Caleb, Reyes-Ruiz, Mauricio, Rolfsmeier, Alex D., Ruhland, Trina R., Salmon, Julien, Santos Sanz, Pablo, Diop, Baidy Demba, Santucho, Marcos Ariel, Sepúlveda Niño, Diana Karina, Sickafoose, Amanda A., Silva, José S., Singer, Kelsi N., Skipper, Joy N., Slivan, Stephen M., Smith, Rose J. C., Spagnotto, Julio C., Stephens, Andrew W., Samaniego, Joseph I., Strabala, Samuel D., European Research Council, European Commission, National Aeronautics and Space Administration (US), Centre National de la Recherche Scientifique (France), Ministerio de Ciencia, Innovación y Universidades (España), German Centre for Air and Space Travel, Department of Energy (US), National Science Foundation (US), Australian National University, Buie, Marc W., Porter, Simon B., Tamblyn, Peter, Terrell, Dirk, Parker, Alex Harrison, Baratoux, David, Kaire, Maram, Leiva, Rodrigo, Verbiscer, Anne J., Zangari, Amanda M., Colas, François, Tamayo, Francisco J., Throop, Henry B., Torres Cañas, Andrés David, Toure, Labaly, Traore, Alassane, Tsang, Constantine C. C., Turner, Jake D., Vanegas, Santiago, Venable, Roger, Wasserman, Lawrence H., Camino López, Matías Aarón, Wilson, John C., Zuluaga, Carlos A., Zuluaga, Jorge I., Benecchi, Susan D., Caspi, Amir, Gwyn, Stephen, Kavelaars, J. J., Ocampo Uría, Adriana C., Rabassa, Jorge, Skrutskie, M. F., Carter, Christian M., Soto, Alejandro, Tanga, Paolo, Young, Eliot F., Stern, S. Alan, Andersen, Bridget C., Arango Pérez, Mauricio E., Arredondo, Anicia, Artola, Rodolfo Alfredo, Bâ, Abdoulaye, Ballet, Romuald, Castro-Chacón, J. H., Blank, Ted, Bop, Cheikh Tidiane, Bosh, Amanda S., Caycedo Desprez, Alfonso, Caycedo Guerra, Nicolás, Conard, Steven J., Dauvergne, Jean-Luc, Dean, Bryan, Dean, Michelle, Desmars, Josselin, González Murillo, Giovanni Francisco, Dieng, Abdou Lahat, Bousso Dieng, Mame Diarra, Diouf, Omar, Dorego, Gualbert Séraphin, Dunham, David W., Dunham, Joan, Durantini Luca, Hugo A., Edwards, Patrick, Erasmus, Nicolas, Faye, Gayane, Grusin, Michael D., Faye, Mactar, Ferrario, Lucas Ezequiel, Ferrell, Chelsea L., Finley, Tiffany J., Fraser, Wesley C., Friedli, Alison J., Galvez Serna, Julián, Garcia-Migani, Esteban A., Genade, Anja, Getrost, Kai, Gurovich, Sebastian, Gil-Hutton, Ricardo A., Gimeno, German N., Golub, Eli Joseph, Hanna, William H., Henn, Santiago M., Hinton, P. C., Hughes, Paul J., Josephs, John David, Jr., Joya, Raul, Kammer, Joshua A., Pinzón, Giovanni, Keeney, Brian A., Keller, John M., Kramer, Emily A., Levine, Stephen E., Lisse, Carey M., Lovell, Amy J., Mackie, Jason A., Makarchuk, Stanislav, Manzano, Luis E., Mbaye, Salma Sylla, Pulver, Eduardo Alejandro, Mbaye, Modou, Melia, Raul Roberto, Moreno, Freddy, Moss, Sean K., Ndaiye, Diene, Ndiaye, Mapathe, Nelson, Matthew J., Olkin, Catherine B., Olsen, Aart M., Ospina Moreno, Victor Jonathan, Quintero, Edwin A., Pasachoff, Jay M., Pereyra, Mariana Belen, Person, Michael J., Regester, Jeffrey R., Resnick, Aaron Caleb, Reyes-Ruiz, Mauricio, Rolfsmeier, Alex D., Ruhland, Trina R., Salmon, Julien, Santos Sanz, Pablo, Diop, Baidy Demba, Santucho, Marcos Ariel, Sepúlveda Niño, Diana Karina, Sickafoose, Amanda A., Silva, José S., Singer, Kelsi N., Skipper, Joy N., Slivan, Stephen M., Smith, Rose J. C., Spagnotto, Julio C., Stephens, Andrew W., Samaniego, Joseph I., and Strabala, Samuel D.

Abstract

We present the results from four stellar occultations by (486958) Arrokoth, the flyby target of the New Horizons extended mission. Three of the four efforts led to positive detections of the body, and all constrained the presence of rings and other debris, finding none. Twenty-five mobile stations were deployed for 2017 June 3 and augmented by fixed telescopes. There were no positive detections from this effort. The event on 2017 July 10 was observed by the Stratospheric Observatory for Infrared Astronomy with one very short chord. Twenty-four deployed stations on 2017 July 17 resulted in five chords that clearly showed a complicated shape consistent with a contact binary with rough dimensions of 20 by 30 km for the overall outline. A visible albedo of 10% was derived from these data. Twenty-two systems were deployed for the fourth event on 2018 August 4 and resulted in two chords. The combination of the occultation data and the flyby results provides a significant refinement of the rotation period, now estimated to be 15.9380 ± 0.0005 hr. The occultation data also provided high-precision astrometric constraints on the position of the object that were crucial for supporting the navigation for the New Horizons flyby. This work demonstrates an effective method for obtaining detailed size and shape information and probing for rings and dust on distant Kuiper Belt objects as well as being an important source of positional data that can aid in spacecraft navigation that is particularly useful for small and distant bodies. © 2020. The American Astronomical Society. All rights reserved.

Published
2020

31. Size and Shape Constraints of (486958) Arrokoth from Stellar Occultations

Author

Buie, Marc W., primary, Porter, Simon B., additional, Tamblyn, Peter, additional, Terrell, Dirk, additional, Parker, Alex Harrison, additional, Baratoux, David, additional, Kaire, Maram, additional, Leiva, Rodrigo, additional, Verbiscer, Anne J., additional, Zangari, Amanda M., additional, Colas, François, additional, Diop, Baidy Demba, additional, Samaniego, Joseph I., additional, Wasserman, Lawrence H., additional, Benecchi, Susan D., additional, Caspi, Amir, additional, Gwyn, Stephen, additional, Kavelaars, J. J., additional, Ocampo Uría, Adriana C., additional, Rabassa, Jorge, additional, Skrutskie, M. F., additional, Soto, Alejandro, additional, Tanga, Paolo, additional, Young, Eliot F., additional, Stern, S. Alan, additional, Andersen, Bridget C., additional, Arango Pérez, Mauricio E., additional, Arredondo, Anicia, additional, Artola, Rodolfo Alfredo, additional, Bâ, Abdoulaye, additional, Ballet, Romuald, additional, Blank, Ted, additional, Bop, Cheikh Tidiane, additional, Bosh, Amanda S., additional, Camino López, Matías Aarón, additional, Carter, Christian M., additional, Castro-Chacón, J. H., additional, Caycedo Desprez, Alfonso, additional, Caycedo Guerra, Nicolás, additional, Conard, Steven J., additional, Dauvergne, Jean-Luc, additional, Dean, Bryan, additional, Dean, Michelle, additional, Desmars, Josselin, additional, Dieng, Abdou Lahat, additional, Bousso Dieng, Mame Diarra, additional, Diouf, Omar, additional, Dorego, Gualbert Séraphin, additional, Dunham, David W., additional, Dunham, Joan, additional, Durantini Luca, Hugo A., additional, Edwards, Patrick, additional, Erasmus, Nicolas, additional, Faye, Gayane, additional, Faye, Mactar, additional, Ferrario, Lucas Ezequiel, additional, Ferrell, Chelsea L., additional, Finley, Tiffany J., additional, Fraser, Wesley C., additional, Friedli, Alison J., additional, Galvez Serna, Julián, additional, Garcia-Migani, Esteban A., additional, Genade, Anja, additional, Getrost, Kai, additional, Gil-Hutton, Ricardo A., additional, Gimeno, German N., additional, Golub, Eli Joseph, additional, González Murillo, Giovanni Francisco, additional, Grusin, Michael D., additional, Gurovich, Sebastian, additional, Hanna, William H., additional, Henn, Santiago M., additional, Hinton, P. C., additional, Hughes, Paul J., additional, Josephs Jr, John David, additional, Joya, Raul, additional, Kammer, Joshua A., additional, Keeney, Brian A., additional, Keller, John M., additional, Kramer, Emily A., additional, Levine, Stephen E., additional, Lisse, Carey M., additional, Lovell, Amy J., additional, Mackie, Jason A., additional, Makarchuk, Stanislav, additional, Manzano, Luis E., additional, Mbaye, Salma Sylla, additional, Mbaye, Modou, additional, Melia, Raul Roberto, additional, Moreno, Freddy, additional, Moss, Sean K., additional, Ndaiye, Diene, additional, Ndiaye, Mapathe, additional, Nelson, Matthew J., additional, Olkin, Catherine B., additional, Olsen, Aart M., additional, Ospina Moreno, Victor Jonathan, additional, Pasachoff, Jay M., additional, Pereyra, Mariana Belen, additional, Person, Michael J., additional, Pinzón, Giovanni, additional, Pulver, Eduardo Alejandro, additional, Quintero, Edwin A, additional, Regester, Jeffrey R., additional, Resnick, Aaron Caleb, additional, Reyes-Ruiz, Mauricio, additional, Rolfsmeier, Alex D., additional, Ruhland, Trina R., additional, Salmon, Julien, additional, Santos-Sanz, Pablo, additional, Santucho, Marcos Ariel, additional, Sepúlveda Niño, Diana Karina, additional, Sickafoose, Amanda A., additional, Silva, José S., additional, Singer, Kelsi N., additional, Skipper, Joy N., additional, Slivan, Stephen M., additional, Smith, Rose J. C., additional, Spagnotto, Julio C., additional, Stephens, Andrew W., additional, Strabala, Samuel D., additional, Tamayo, Francisco J., additional, Throop, Henry B., additional, Torres Cañas, Andrés David, additional, Toure, Labaly, additional, Traore, Alassane, additional, Tsang, Constantine C. C., additional, Turner, Jake D., additional, Vanegas, Santiago, additional, Venable, Roger, additional, Wilson, John C., additional, Zuluaga, Carlos A., additional, and Zuluaga, Jorge I., additional

Published
2020
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32. Disentangling the Mesoscale Ocean-Atmosphere Interactions

Author

Renault, L., Masson, S., Oerder, V., Jullien, Swen, Colas, François, Renault, L., Masson, S., Oerder, V., Jullien, Swen, and Colas, François

Abstract

In the past decades, the use of scatterometer data allowed to demonstrate the global ubiquity of the Ocean Mesoscale Thermal FeedBack (TFB) and Current FeedBack (CFB) effects on surface winds and stress. Understanding these air‐sea interactions is of uttermost importance as the induced atmospheric anomalies partly control the ocean circulation, and, thus, can influence the Earth Climate. Whether the TFB and CFB effects can be disentangled, and whether satellite scatterometers can properly reveal them, remain rather unclear. Here, using satellite observations and ocean‐atmosphere coupled mesoscale simulations over 45° S‐45° N, we show that the CFB effect can be properly characterized and unraveled from that due to the TFB. We demonstrate that the TFB can be unambiguously characterized by its effect on the stress (and wind) divergence and magnitude. However, its effect on the wind and stress curl is contaminated by the CFB and, thus, can not be estimated from scatterometer data. Finally, because scatterometers provide equivalent neutral stability winds relative to the oceanic currents, they cannot characterize adequately the CFB wind response and overestimate the TFB wind response by ≈ 25%. Surface stress appears to be the more appropriate variable to consider from scatterometer data.

Published
2019
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33. Asteroid pairs: A complex picture

Author

Junta de Andalucía, Slovak Academy of Sciences, Shota Rustaveli National Science Foundation, Ministry of Innovative Development (Uzbekistan), Charles University (Czech Republic), Ministerio de Economía, Industria y Competitividad (España), l'Observatoire de Paris, Government of Czech Republic, Pravec, P., Fatka, P., Vokrouhlický, D., Scheirich, P., Durech, J., Scheeres, D.J., Kušnirák, P., Hornoch, K., Galád, A., Pray, D.P., Krugly, Y.N., Burkhonov, O., Ehgamberdiev, S.A., Pollock, J., Moskovitz, N., Thirouin, A., Ortiz, José Luis, Morales, Nicolás, Husárik, M., Inasaridze, R.Y., Oey, J., Polishook, D., Hanuš, J., Kučáková, Hana, Vraštil, J., Világi, J., Gajdoš, Š., Kornoš, L., Vereš, P., Gaftonyuk, N.M., Hromakina, T., Sergeyev, A.V., Slyusarev, I.G., Ayvazian, V.R., Cooney, W.R., Gross, J., Terrell, D., Colas, François, Vachier, F., Slivan, S., Skiff, B., Marchis, F., Ergashev, K.E., Kim, D. H., Aznar, A., Serra-Ricart, M., Behrend, R., Roy, R., Manzini, F., Junta de Andalucía, Slovak Academy of Sciences, Shota Rustaveli National Science Foundation, Ministry of Innovative Development (Uzbekistan), Charles University (Czech Republic), Ministerio de Economía, Industria y Competitividad (España), l'Observatoire de Paris, Government of Czech Republic, Pravec, P., Fatka, P., Vokrouhlický, D., Scheirich, P., Durech, J., Scheeres, D.J., Kušnirák, P., Hornoch, K., Galád, A., Pray, D.P., Krugly, Y.N., Burkhonov, O., Ehgamberdiev, S.A., Pollock, J., Moskovitz, N., Thirouin, A., Ortiz, José Luis, Morales, Nicolás, Husárik, M., Inasaridze, R.Y., Oey, J., Polishook, D., Hanuš, J., Kučáková, Hana, Vraštil, J., Világi, J., Gajdoš, Š., Kornoš, L., Vereš, P., Gaftonyuk, N.M., Hromakina, T., Sergeyev, A.V., Slyusarev, I.G., Ayvazian, V.R., Cooney, W.R., Gross, J., Terrell, D., Colas, François, Vachier, F., Slivan, S., Skiff, B., Marchis, F., Ergashev, K.E., Kim, D. H., Aznar, A., Serra-Ricart, M., Behrend, R., Roy, R., and Manzini, F.

Abstract

We studied a sample of 93 asteroid pairs, i.e., pairs of genetically related asteroids that are on highly similar heliocentric orbits. We estimated times elapsed since separation of pair members (i.e., pair age) that are between 7 × 10 yr and a few 10 yr. With photometric observations, we derived the rotation periods P for all the primaries (i.e., the larger members of asteroid pairs) and a sample of secondaries (the smaller pair members). We derived the absolute magnitude differences of the studied asteroid pairs that provide their mass ratios q. For a part of the studied pairs, we refined their WISE geometric albedos and collected or estimated their taxonomic classifications. For 17 asteroid pairs, we also determined their pole positions. In two pairs where we obtained the spin poles for both pair components, we saw the same sense of rotation for both components and constrained the angles between their original spin vectors at the time of their separation. We found that the primaries of 13 asteroid pairs in our sample are actually binary or triple systems, i.e., they have one or two bound, orbiting secondaries (satellites). As a by-product, we found also 3 new young asteroid clusters (each of them consisting of three known asteroids on highly similar heliocentric orbits). We compared the obtained asteroid pair data with theoretical predictions and discussed their implications. We found that 86 of the 93 studied asteroid pairs follow the trend of primary rotation period vs mass ratio that was found by Pravec et al. (2010). Of the 7 outliers, 3 appear insignificant (may be due to our uncertain or incomplete knowledge of the three pairs), but 4 are high mass ratio pairs that were unpredicted by the theory of asteroid pair formation by rotational fission. We discuss a (remotely) possible way that they could be created by rotational fission of flattened parent bodies followed by re-shaping of the formed components. The 13 asteroid pairs with binary primaries are partic

Published
2019

34. Forcings and Evolution of the 2017 Coastal El Niño Off Northern Peru and Ecuador

Author

Echevin, Vincent, Colas, François, Espinoza Morriberón, Dante, Vásquez, Luis, Anculle, Tony, Gutiérrez, Dimitri, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Instituto del Mar del Peru (IMARPE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)

Subjects
extreme events, mechanical processes, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, coastal waters, wind, El Niño, oceanography, precipitation, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, El Nino
Abstract

International audience; El Niño events, in particular the eastern Pacific type, have a tremendous impact on the marine ecosystem and climate conditions in the eastern South Pacific. During such events, the accumulation of anomalously warm waters along the coast favors intense rainfall. The upwelling of nutrient-replete waters is stopped and the marine ecosystem is strongly impacted. These events are generally associated with positive surface temperature anomalies in the central and eastern equatorial Pacific. During austral summer 2017, a strong surface temperature anomaly reaching ∼3-4 • C off Northern Peru and Ecuador led to intense coastal precipitations. However, neutral temperature anomalies were recorded in the equatorial Pacific. Using in situ measurements, satellite observations, and simulations from an eddy-resolving regional ocean circulation model, we investigated the physical processes triggering this peculiar 'coastal El Niño.' Its impact on the regional ocean circulation and heat budget off northern Peru and Ecuador was assessed. Using model sensitivity experiments, we investigated the respective roles of the equatorial Kelvin waves and local wind anomalies in driving the anomalously high nearshore sea surface temperature (SST). The atmospheric teleconnections which triggered the event were investigated using reanalysis data.

Published
2018

35. GRAAL project: in situ optical detection of dust concentration from the Earth’s orbit

Author

Renard, Jean-Baptiste, Moussis, Olivier, Colas, François, Levasseur-Regourd, Anny Chantal, Cardon, Catherine, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), 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), Observatoire de Paris - Site de Paris (OP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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)-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), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], Physics::Atmospheric and Oceanic Physics
Abstract

International audience; We present here a new concept of instrument, basedof optical aerosols counter, to better estimate theconcentration and size distribution of incominginterplanetary material in the Earth’s atmosphere.This concept, called GRAAL, could be in the Earth’sorbit onboard a micro-satellite or within theInternational Space Station

Published
2018

36. The young Datura asteroid family

Author

Vokrouhlický, D., Pravec, P., Ďurech, J., Bolin, B., Jedicke, R., Kušnirák, P., Galad, A., Hornoch, K., Kryszczyńska, A., Colas, François, Moskovitz, N., Thirouin, A., Nesvorny, D., Institute of Astronomy, Charles University [Prague] (CU), Ondřejov Observatory of the Prague Astronomical Institute, Czech Academy of Sciences [Prague] (CAS), Astronomical Institute of Charles University, Astronomical Institute of the Czech Academy of Sciences (ASU / CAS), Astronomical Observatory [Poznan], Adam Mickiewicz University in Poznań (UAM), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU]Sciences of the Universe [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

37. A New, Long-lived, Jupiter Mesoscale Wave Observed at Visible Wavelengths

Author

Simon, Amy A., primary, Hueso, Ricardo, additional, Iñurrigarro, Peio, additional, Sánchez-Lavega, Agustín, additional, Morales-Juberías, Raúl, additional, Cosentino, Richard, additional, Fletcher, Leigh N., additional, Wong, Michael H., additional, Hsu, Andrew I., additional, Pater, Imke de, additional, Orton, Glenn S., additional, Colas, François, additional, Delcroix, Marc, additional, Peach, Damian, additional, and Gómez-Forrellad, Josep-María, additional

Published
2018
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38. The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation

Author

Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Ortiz Moreno, José Luis, Santos Sanz, Pablo, Sicardy, B., Benedetti-Rossi, G., Bérard, D., Morales Palomino, Nicolás, Duffard, René, Braga-Ribas, F., Hopp, U., Ries, C., Nascimbeni, V., Marzari, F., Granata, V., Pál, András, Kiss, C., Pribulla, T., Komžík, R., Hornoch, K., Pravec, Petr, Bacci, P., Maestripieri, M., Nerli, L., Mazzei, L., Bachini, M., Martinelli, F., Succi, G., Ciabattari, F., Mikuz, H., Carbognani, A., Gaehrken, B., Mottola, S., Hellmich, S., Rommel, F.L., Fernández-Valenzuela, Estela, Campo Bagatin, Adriano, Cikota, S., Cikota, A., Lecacheux, J., Vieira-Martins, R., Camargo, J.I.B., Assafin, M., Colas, François, Behrend, Raoul, Desmars, Josselin, Meza, E., Alvarez-Candal, Alvaro, Beisker, W., Gomes-Junior, A.R., Morgado, B.E., Roques, F., Vachier, Frédéric, Berthier, Jérôme, Mueller, T.G., Madiedo, J.M., Unsalan, O., Sonbas, E., Karaman, N., Erece, O., Koseoglu, D.T., Ozisik, T., Kalkan, S., Guney, Y., Niaei, M.S., Satir, O., Yesilyaprak, C., Puskullu, C., Kabas, A., Demircan, O., Alikakos, J., Charmandaris, V., Leto, G., Ohlert, J., Christille, J.M., Szakáts, Róbert, Takácsné Farkas, A., Varga-Verebélyi, E., Marton, G., Marciniak, Anna, Bartczak, Przemyslaw, Santana-Ros, Toni, Butkiewicz-Bąk, Magdalena, Dudziński, Grzegorz, Alí-Lagoa, Víctor, Gazeas, K., Tzouganatos, L., Paschalis, N., Tsamis, V., Sánchez-Lavega, A., Pérez-Hoyos, S., Hueso, R., Guirado, J.C., Peris, V., Iglesias-Marzoa, R., Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Ortiz Moreno, José Luis, Santos Sanz, Pablo, Sicardy, B., Benedetti-Rossi, G., Bérard, D., Morales Palomino, Nicolás, Duffard, René, Braga-Ribas, F., Hopp, U., Ries, C., Nascimbeni, V., Marzari, F., Granata, V., Pál, András, Kiss, C., Pribulla, T., Komžík, R., Hornoch, K., Pravec, Petr, Bacci, P., Maestripieri, M., Nerli, L., Mazzei, L., Bachini, M., Martinelli, F., Succi, G., Ciabattari, F., Mikuz, H., Carbognani, A., Gaehrken, B., Mottola, S., Hellmich, S., Rommel, F.L., Fernández-Valenzuela, Estela, Campo Bagatin, Adriano, Cikota, S., Cikota, A., Lecacheux, J., Vieira-Martins, R., Camargo, J.I.B., Assafin, M., Colas, François, Behrend, Raoul, Desmars, Josselin, Meza, E., Alvarez-Candal, Alvaro, Beisker, W., Gomes-Junior, A.R., Morgado, B.E., Roques, F., Vachier, Frédéric, Berthier, Jérôme, Mueller, T.G., Madiedo, J.M., Unsalan, O., Sonbas, E., Karaman, N., Erece, O., Koseoglu, D.T., Ozisik, T., Kalkan, S., Guney, Y., Niaei, M.S., Satir, O., Yesilyaprak, C., Puskullu, C., Kabas, A., Demircan, O., Alikakos, J., Charmandaris, V., Leto, G., Ohlert, J., Christille, J.M., Szakáts, Róbert, Takácsné Farkas, A., Varga-Verebélyi, E., Marton, G., Marciniak, Anna, Bartczak, Przemyslaw, Santana-Ros, Toni, Butkiewicz-Bąk, Magdalena, Dudziński, Grzegorz, Alí-Lagoa, Víctor, Gazeas, K., Tzouganatos, L., Paschalis, N., Tsamis, V., Sánchez-Lavega, A., Pérez-Hoyos, S., Hueso, R., Guirado, J.C., Peris, V., and Iglesias-Marzoa, R.

Abstract

Haumea—one of the four known trans-Neptunian dwarf planets—is a very elongated and rapidly rotating body1, 2, 3. In contrast to other dwarf planets4, 5, 6, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system7, and the Centaur Chiron was later found to possess something similar to Chariklo’s rings8, 9. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea’s equator and the orbit of its satellite Hi’iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea’s spin period—that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea’s largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates1, 10, 11. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

Published
2017

39. Comet 332P-A/IKEYA-MURAKAMI

Author

Seki, T., Colas, François, Maquet, Lucie, Pierret, Frédéric, Kowalski, R. A., Christensen, E. J., Fuls, D. C., Gibbs, A. R., Grauer, A. D., Johnson, Jennifer A., Larson, S. M., Leonard, G. J., Matheny, R. G., Seaman, R. L., Shelly, F. C., Ikari, Y., Muller, J. J., Rinner, Claudine, Kugel, F., Diepvens, A., Dekelver, P.-J., Cuppens, W., González, J., Williams, G. V., Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), and 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

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Not Available

Published
2016

40. Do submesoscale frontal processes ventilate the oxygen minimum zone off Peru?

Author

Thomsen, Soeren, Kanzow, Torsten, Colas, François, Echevin, Vincent, Krahmann, Gerd, Engel, Anja, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Processus de couplage à Petite Echelle, Ecosystèmes et Prédateurs Supérieurs (PEPS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636))

Subjects
upwelling, oxygen minimum zone, ventilation, Peru, [SDE]Environmental Sciences, submesoscale, subduction, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; The Peruvian upwelling system encompasses the most intense and shallowest oxygen minimum zone (OMZ) in the ocean. This system shows pronounced submesoscale activity like filaments and fronts. We carried out glider-based observations off Peru during austral summer 2013 to investigate whether submesoscale frontal processes ventilate the Peruvian OMZ. We present observational evidence for the subduction of highly oxygenated surface water in a submesoscale cold filament. The subduction event ventilates the oxycline but does not reach OMZ core waters. In a regional submesoscale-permitting model we study the pathways of newly upwelled water. About 50% of upwelled virtual floats are subducted below the mixed layer within 5 days emphasizing a hitherto unrecognized importance of subduction for the ventilation of the Peruvian oxycline.

Published
2016

41. Modelling the seasonal dynamics of the Peru-Chile Undercurrent off Central Chile (30&8211;40°S)

Author

Vergara, O.A., Echevin, Vincent, Sepulveda, H.H., Colas, François, and Quinones, R.A.

Abstract

The seasonal variability of the hydrology and the poleward subsurface Peru-Chile Undercurrent (PCUC) off the central Chilean coast (29–41°S) were examined using a high-resolution regional model. The model realistically reproduced observed sea level variability, such as intense anticyclonic eddies, the offshore intensification of the poleward flow and the reduced nearshore equatorward flow during autumn, as well as the equatorward intensification of nearshore meandering flow during spring. Values for geostrophic eddy kinetic energy were high along the coast between 30° and 37°S, and lower south of this area. The modelled poleward undercurrent showed latitudinal variability in velocity and transport. The maximum average transport reported was 0.8 Sv near 30°S, consistent with previous modelling studies and estimations derived from in situ observations. The poleward reduction in undercurrent strength was shown to be partly generated by the poleward decrease in wind stress curl and by the formation of a westward jet near 35°S associated with westward-propagating eddies. A Lagrangian analysis of the modelled water parcels transported by the undercurrent shows that only 14–20% of the subsurface floats transported by the undercurrent upwelled into the surface layer within the subsequent six months after their release. The floats remaining within the subsurface layer were likely transported further south by the current, offshore by westward-propagating eddies or equatorward by the deeper part of the surface coastal current.

Published
2016

42. Deep winds beneath Saturn’s upper clouds from a seasonal long-lived planetary-scale storm

Author

Sánchez-Lavega, A., del Río-Gaztelurrutia, T., Hueso, R., Gómez-Forrellad, J. M., Sanz-Requena, J. F., Legarreta, J., García-Melendo, E., Colas, François, Lecacheux, Jean, Fletcher, L. N., Barrado y Navascués, D., Parker, D., International Outer Planet Watch Team, The, Departamento de Fisica Aplicada [Bilbao], Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Fundació Privada Observatori Esteve Duran, Universidad europea Miguel de Cervantes (UEMC), Departamento de Ingenieria de Sistemas y Automatica [Bilbao], Institut de Ciencies de l'Espai [Barcelona] (ICE-CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford, Centro Astronómico Hispano Alemán, Observatorio de Calar Alto (CAHA), Association of Lunar and Planetary Observers (ALPO), The International Outer Planet Watch Team (IOPW), 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), University of Oxford [Oxford], Universidad del Pais Vasco / Euskal Herriko Unibertsitatea ( UPV/EHU ), Universidad europea Miguel de Cervantes, Institut de Ciencies de l'Espai [Barcelona] ( ICE-CSIC ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Institut de Mécanique Céleste et de Calcul des Ephémérides ( IMCCE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), 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 Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] ( AOPP ), Observatorio de Calar Alto, Centro Astronómico Hispano Alemán, Association of Lunar and Planetary Observers ( ALPO ), Association of Lunar and Planetary Observers, and The International Outer Planet Watch Team ( IOPW )

Subjects
Convection, Multidisciplinary, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, Physics, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Storm, Atmospheric sciences, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Troposphere, Planetary science, [ PHYS.ASTR.EP ] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 13. Climate action, Planet, 0103 physical sciences, Convective storm detection, Thunderstorm, Geology and geophysics, Planetary sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Great White Spot
Abstract

Six Great White Spot (GWS) events have been observed in the atmosphere of Saturn since 1876. These giant convective storms occur roughly once every Saturnian year (equal to 29.5 Earth years). The sixth GWS erupted in December 2010 and has been the subject of intense observation. Two papers in this issue present the details of some of these observations. Sanchez-Lavega et al. report that the storm developed at northern latitudes in the peak of a weak westward jet during early northern springtime. The storm head moved faster than the jet and triggered a disturbance that circled the planet. Numerical simulations show that Saturn's winds extend without decay deep down into the weather layer. Fischer et al. report that the storm reached a width of 10,000 kilometres within three weeks. Its lightning flash rates are an order of magnitude greater than those seen in previous storms, peaking at more than 10 flashes per second. Convective storms occur regularly in Saturn’s atmosphere1,2,3,4. Huge storms known as Great White Spots, which are ten times larger than the regular storms, are rarer and occur about once per Saturnian year (29.5 Earth years). Current models propose that the outbreak of a Great White Spot is due to moist convection induced by water5,6. However, the generation of the global disturbance and its effect on Saturn’s permanent winds1,7 have hitherto been unconstrained8 by data, because there was insufficient spatial resolution and temporal sampling9,10,11 to infer the dynamics of Saturn’s weather layer (the layer in the troposphere where the cloud forms). Theoretically, it has been suggested that this phenomenon is seasonally controlled5,9,10. Here we report observations of a storm at northern latitudes in the peak of a weak westward jet during the beginning of northern springtime, in accord with the seasonal cycle but earlier than expected. The storm head moved faster than the jet, was active during the two-month observation period, and triggered a planetary-scale disturbance that circled Saturn but did not significantly alter the ambient zonal winds. Numerical simulations of the phenomenon show that, as on Jupiter12, Saturn’s winds extend without decay deep down into the weather layer, at least to the water-cloud base at pressures of 10–12 bar, which is much deeper than solar radiation penetrates.

Published
2011

43. Multi-instrumental observations of the 2014 Ursid meteor outburst

Author

Moreno-Ibáñez, Manuel, primary, Trigo-Rodríguez, Josep M., additional, Madiedo, José María, additional, Vaubaillon, Jérémie, additional, Williams, Iwan P., additional, Gritsevich, Maria, additional, Morillas, Lorenzo G., additional, Blanch, Estefanía, additional, Pujols, Pep, additional, Colas, François, additional, and Dupouy, Philippe, additional

Published
2017
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44. Changement climatique : quels défis pour le Sud ?

Author

Colas, François, Echevin, Vincent, Peugeot, Christophe, Terray, Pascal, Sultan, Benjamin, Vischel, T., Reinert, M., Janicot, Serge (ed.), Aubertin, Catherine (ed.), Bernoux, Martial (ed.), Dounias, Edmond (ed.), Guégan, Jean-François (ed.), Lebel, Thierry (ed.), Mazurek, Hubert (ed.), Sultan, Benjamin (ed.), Sokona, Y. (pref.), and Moatti, Jean-Paul (pref.)

Published
2015

45. Climate change : what challenges for the South ?

Author

Colas, François, Echevin, Vincent, Peugeot, Christophe, Terray, Pascal, Sultan, Benjamin, Vischel, T., Reinert, M., Janicot, Serge (ed.), Aubertin, Catherine (ed.), Bernoux, Martial (ed.), Dounias, Edmond (ed.), Guégan, Jean-François (ed.), Lebel, Thierry (ed.), Mazurek, Hubert (ed.), Sultan, Benjamin (ed.), Sokona, Y. (pref.), and Moatti, Jean-Paul (pref.)

Published
2015

46. Mesoscale SST–wind stress coupling in the Peru–Chile current system: Which mechanisms drive its seasonal variability?

Author

Oerder, Vera, Colas, François, Echevin, Vincent, Masson, Sebastien, Hourdin, Christophe, Jullien, Swen, Madec, Gurvan, Lemarie, Florian, Oerder, Vera, Colas, François, Echevin, Vincent, Masson, Sebastien, Hourdin, Christophe, Jullien, Swen, Madec, Gurvan, and Lemarie, Florian

Abstract

Satellite observations and a high-resolution regional ocean–atmosphere coupled model are used to study the air/sea interactions at the oceanic mesoscale in the Peru–Chile upwelling current system. Coupling between mesoscale sea surface temperature (SST) and wind stress (WS) intensity is evidenced and characterized by correlations and regression coefficients. Both the model and the observations display similar spatial and seasonal variability of the coupling characteristics that are stronger off Peru than off Northern Chile, in relation with stronger wind mean speed and steadiness. The coupling is also more intense during winter than during summer in both regions. It is shown that WS intensity anomalies due to SST anomalies are mainly forced by mixing coefficient anomalies and partially compensated by wind shear anomalies. A momentum balance analysis shows that wind speed anomalies are created by stress shear anomalies. Near-surface pressure gradient anomalies have a negligible contribution because of the back-pressure effect related to the air temperature inversion. As mixing coefficients are mainly unchanged between summer and winter, the stronger coupling in winter is due to the enhanced large-scale wind shear that enables a more efficient action of the turbulent stress perturbations. This mechanism is robust as it does not depend on the choice of planetary boundary layer parameterization.

Published
2016
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48. Origin and fate of upwelled waters in the Canary Upwelling as determined through numerical float experiments

Author

Mason, Evan, Colas, François, and Pelegrí, Josep Lluís

Abstract

I Encuentro de la Oceanografía Física Española (EOF), 13-15 de octubre 2010, Barcelona, The Canary Upwelling System (CUS) off northwest Africa forms one of the four major eastern boundary upwellings of the world ocean. The region is highly productive and supports an important fishing industry. At the surface, the upwelling is manifest as a narrow band of relatively cool water at the coast, whose offshore boundary frequently extends into the open ocean in the form of filaments and eddies. Whilst these observed features and their seasonality are well described in the literature, rather little is known about the source waters that feed into the upwelling at depth, and their fate once at the surface. Numerical float experiments are carried out utilising 3‐dimensional velocity fields from a high‐resolution numerical model simulation of the northeast Atlantic. Floats are released on the shelf region off northwest Africa. Both 'forwards' and 'backwards' runs are performed to determine the possible pathways of water parcels that traverse the CUS

Published
2010

49. Lagrangian circulation of the North Atlantic Central Water over the abyssal plain and continental slopes of the Bay of Biscay: description of selected mesoscale features

Author

Serpette, Alain, Le Cann, Bernard, and Colas, François

Subjects
Bay of Biscay, Lagrangian floats and surface drifters, slope current, mesoscale eddies, slope ocean exchanges, Golfo de Vizcaya, flotadores Lagrangianos y boyas de deriva, corriente de talud, remolinos de meso-escala, intercambios entre el talud y el océano
Abstract

Between 1994 and 2001, several experiments (ARCANE, SEFOS, INTERAFOS) were conducted to directly measure the general and mesoscale Lagrangian circulations over the Bay of Biscay abyssal plain and slopes. Two levels (~100 m and ~450 m) were selected to cover the North Atlantic Central Water range. Two types of Lagrangian instruments, drogued surface drifters tracked by satellite (Surdrift) and acoustically tracked subsurface floats (Rafos and Marvor), were used. Overall, more than 36 instrument-years were collected in the Bay of Biscay region (43-49°N, 01-12°W). The weak general circulation in the Bay of Biscay is seen to be highly influenced by the occurrence of several mesoscale coherent features, notably slope currents and eddies, and these affect the exchanges between the abyssal plain and the slopes. The objective of this paper is to depict some specific examples of the observed mesoscale field. Selected float trajectories are shown and used to discuss observations of slope currents and of both anticyclonic and cyclonic eddies. Slope currents exhibit alternation of poleward and equatorward directions, depending on both the period and the geographic area considered. Although the generation process of mesoscale eddies is difficult to observe unambiguously from Lagrangian instruments, eddies are nevertheless ubiquitous over the abyssal plain. Some characteristics of the observed cyclonic and anticyclonic eddies are presented. Smaller anticyclones, localised over the outer shelf and interpreted in terms of ajustment of slope water intrusions, are also depicted., Diferentes proyectos (campañas ARCANE, SEFOS, INTERAFOS) han sido llevados a cabo entre 1994 y 2001 para determinar la circulación Lagrangiana, general y de meso-escala, sobre la planicie abisal y del talud del Golfo de Vizcaya. Dos niveles fueron seleccionados para seguir el Agua Central del Atlántico-Norte (100 m y 450 m). Para esto se han usado boyas de deriva en superficie (de tipo Surdrifts de inmersión constante, seguidas por satélite) y flotadores en profundidad localizados por red acústica (Rafos y Marvor). Casi 36 años-flotadores han sido obtenidos por esas experiencias en la región del Golfo de Vizcaya. La circulación general del Golfo se muestra débil, al parecer muy influida por la presencia de procesos de meso-escala, como de corrientes del talud y remolinos que participan en los intercambios entre la planicie abisal y el talud. El objetivo de este trabajo consiste en describir específicamente algunos eventos de meso-escala que han sido observados. Algunas trayectorias de flotadores fueron usadas para describir y discutir las observaciones de las corrientes del talud y de remolinos ciclónicos y anticiclónicos. Las corrientes del talud muestran una estructura alternada, en dirección hacia el polo o el ecuador, según la época del año y la región consideradas. Aunque es difícil observar el proceso de formación de los remolinos de meso-escala con flotadores Lagrangianos, éstas estructuras son muy numerosas sobre la planicie abisal. Diferentes características pueden ser descritas con los datos recogidos de remolinos ciclónicos y anticiclónicos. Además, los remolinos anti-ciclónicos de más pequeña escala son observados en la parte externa de la plataforma, y pueden ser interpretados en términos de ajuste causados por la intrusión del agua proveniente del talud.

Published
2006
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50. Observations of Comets

Author

Ticha, J., Tichy, M., Devyatkin, A. V., Bekhteva, A. S., Gorshanov, D. L., Kouprianov, V. V., Aleshkina, E. Yu., Krakosevich, O. V., Barshevich, K. V., Ibragimov, F. M., Baturina, G. D., Tesi, L., Tombelli, M., Fagioli, G., Mazzucato, M., Dolfi, F., Forti, G., Galád, Adrián, Világi, Jozef, Kornos, Leonard, Marinello, W., Micheli, Marco, Pizzetti, G., Soffiantini, A., Apitzsch, R., Galli, G., Buzzi, L., Naves, R., Campas, M., Hasubick, W., Reina, E., Kadota, K., Herald, Dave, Mcandrew, S. G., Sanchez, A., Sarneczky, K., W Christie, G., Gonano, M., Gonano, V., Sostero, G., Guido, E., Kelemen, J., Colas, François, Lecacheux, Jean, Frappa, Eric, Bambery, R., Hicks, M., Lawrence, Kenneth J., Helin, E., Thicksten, R., Tucker, R., Block, M., Block, A. F. Tubbiolo T. H. Bressi M., Mcmillan, R. S., van Ness, M. E., Skiff, B. A., Koehn, B. W., Kowalski, R. A., Christensen, E. J., Hill, R., Larson, S. M., Beshore, Edward C., Garradd, G. J., Grauer, A. D., Mcnaught, R. H., Bezpalko, M., Manguso, L., Torres, D., Kracke, R., Milner, A., Love, H., Stuart, J., Sayer, R., Evans, J., Kommers, J., Salvo, R., Durig, D. T., Dyvig, R., Reddy, V., Castellano, J., Vidal, J. R., Garcia, F., Cortes, E., Takbou, S., Kocher, P., Brinkmann, B., Valentini, S., Peretto, G., Denzau, H., Kyrylenko, D., Ivashchenko, Yury, Kugel, F., Shimomoto, S., Ohshima, Y., Sugiyama, Y., Levy, D., Levy, W., Glinos, T., Yeung, W. K. Y., Sherrod, P. C., Jacques, C., Pimentel, E., Morales, Rafael, Doreste, J. L., Pastor, Sergio, Reyes, J. A., Climent, T., Marsden, Brian G., 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, and 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)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2006

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