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1. Constraints on the structure and seasonal variations of Triton’s atmosphere from the 5 October 2017 stellar occultation and previous observations

Author

J. Marques Oliveira, B. Sicardy, A. R. Gomes-Júnior, J. L. Ortiz, D. F. Strobel, T. Bertrand, F. Forget, E. Lellouch, J. Desmars, D. Bérard, A. Doressoundiram, J. Lecacheux, R. Leiva, E. Meza, F. Roques, D. Souami, T. Widemann, P. Santos-Sanz, N. Morales, R. Duffard, E. Fernández-Valenzuela, A. J. Castro-Tirado, F. Braga-Ribas, B. E. Morgado, M. Assafin, J. I. B. Camargo, R. Vieira-Martins, G. Benedetti-Rossi, S. Santos-Filho, M. V. Banda-Huarca, F. Quispe-Huaynasi, C. L. Pereira, F. L. Rommel, G. Margoti, A. Dias-Oliveira, F. Colas, J. Berthier, S. Renner, R. Hueso, S. Pérez-Hoyos, A. Sánchez-Lavega, J. F. Rojas, W. Beisker, M. Kretlow, D. Herald, D. Gault, K.-L. Bath, H.-J. Bode, E. Bredner, K. Guhl, T. V. Haymes, E. Hummel, B. Kattentidt, O. Klös, A. Pratt, B. Thome, C. Avdellidou, K. Gazeas, E. Karampotsiou, L. Tzouganatos, E. Kardasis, A. A. Christou, E. M. Xilouris, I. Alikakos, A. Gourzelas, A. Liakos, V. Charmandaris, M. Jelínek, J. Štrobl, A. Eberle, K. Rapp, B. Gährken, B. Klemt, S. Kowollik, R. Bitzer, M. Miller, G. Herzogenrath, D. Frangenberg, L. Brandis, I. Pütz, V. Perdelwitz, G. M. Piehler, P. Riepe, K. von Poschinger, P. Baruffetti, D. Cenadelli, J.-M. Christille, F. Ciabattari, R. Di Luca, D. Alboresi, G. Leto, R. Zanmar Sanchez, P. Bruno, G. Occhipinti, L. Morrone, L. Cupolino, A. Noschese, A. Vecchione, C. Scalia, R. Lo Savio, G. Giardina, S. Kamoun, R. Barbosa, R. Behrend, M. Spano, E. Bouchet, M. Cottier, L. Falco, S. Gallego, L. Tortorelli, S. Sposetti, J. Sussenbach, F. Van Den Abbeel, P. André, M. Llibre, F. Pailler, J. Ardissone, M. Boutet, J. Sanchez, M. Bretton, A. Cailleau, V. Pic, L. Granier, R. Chauvet, M. Conjat, J. L. Dauvergne, O. Dechambre, P. Delay, M. Delcroix, L. Rousselot, J. Ferreira, P. Machado, P. Tanga, J.-P. Rivet, E. Frappa, M. Irzyk, F. Jabet, M. Kaschinski, A. Klotz, Y. Rieugnie, A. N. Klotz, O. Labrevoir, D. Lavandier, D. Walliang, A. Leroy, S. Bouley, S. Lisciandra, J.-F. Coliac, F. Metz, D. Erpelding, P. Nougayrède, T. Midavaine, M. Miniou, S. Moindrot, P. Morel, B. Reginato, E. Reginato, J. Rudelle, B. Tregon, R. Tanguy, J. David, W. Thuillot, D. Hestroffer, G. Vaudescal, D. Baba Aissa, Z. Grigahcene, D. Briggs, S. Broadbent, P. Denyer, N. J. Haigh, N. Quinn, G. Thurston, S. J. Fossey, C. Arena, M. Jennings, J. Talbot, S. Alonso, A. Román Reche, V. Casanova, E. Briggs, R. Iglesias-Marzoa, J. Abril Ibáñez, M. C. Díaz Martín, H. González, J. L. Maestre García, J. Marchant, I. Ordonez-Etxeberria, P. Martorell, J. Salamero, F. Organero, L. Ana, F. Fonseca, V. Peris, O. Brevia, A. Selva, C. Perello, V. Cabedo, R. Gonçalves, M. Ferreira, F. Marques Dias, A. Daassou, K. Barkaoui, Z. Benkhaldoun, M. Guennoun, J. Chouqar, E. Jehin, C. Rinner, J. Lloyd, M. El Moutamid, C. Lamarche, J. T. Pollock, D. B. Caton, V. Kouprianov, B. W. Timerson, G. Blanchard, B. Payet, A. Peyrot, J.-P. Teng-Chuen-Yu, J. Françoise, B. Mondon, T. Payet, C. Boissel, M. Castets, W. B. Hubbard, R. Hill, H. J. Reitsema, O. Mousis, L. Ball, G. Neilsen, S. Hutcheon, K. Lay, P. Anderson, M. Moy, M. Jonsen, I. Pink, R. Walters, B. Downs, Ministerio de Ciencia e Innovación (España), Junta de Andalucía, European Research Council, European Commission, Fundação para a Ciência e a Tecnologia (Portugal), 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), Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Johns Hopkins University (JHU), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut Polytechnique des Sciences Avancées (IPSA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Comisión Nacional de Investigación y Desarrollo Aeroespacial (CONIDA), Observatorio Astronómico de Moquegua, Florida Space Institute [Orlando] (FSI), University of Central Florida [Orlando] (UCF), Federal University of Technology - Paraná (UTFPR), Observatório Nacional [Rio de Janeiro] (ON), Ministério da Ciência, Tecnologia, Inovações e Comunicações (MCTIC), Universidade Federal do Rio de Janeiro (UFRJ), Polo Educacional Sesc [Rio de Janeiro], Université de Lille, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), International Occultation Timing Association (IOTA), Internationale Amateursternwarte [Mittenwalde] (IAS), Société Astronomique de France (SAF), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11), Analyse, ingénierie et contrôle des micro-organismes (MICROCOSME), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Grenoble Alpes (UGA), Laboratoire Ondes et Matière d'Aquitaine (LOMA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Project: 669416,H2020,ERC-2014-ADG,LUCKY STAR(2015), and European Project: 687378,H2020,H2020-COMPET-2015,SBNAF(2016)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: atmospheres, planets and satellites: physical evolution, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], photometric [Techniques], FOS: Physical sciences, Astronomy and Astrophysics, methods: data analysis, techniques: photometric, Space and Planetary Science, [SDU]Sciences of the Universe [physics], atmospheres [Planets and satellites], observational [Methods], methods: observational, data analysis [Methods], physical evolution [Planets and satellites], Astrophysics - Earth and Planetary Astrophysics
Abstract

J.M.O. acknowledges financial support from the Portuguese Foundation for Science and Technology (FCT) and the European Social Fund (ESF) through the PhD grant SFRH/BD/131700/2017. The work leading to these results has received funding from the European Research Council under the European Community's H2020 2014-2021 ERC grant Agreement nffi 669416 "Lucky Star". We thank S. Para who supported some travels to observe the 5 October 2017 occultation. T.B. was supported for this research by an appointment to the National Aeronautics and Space Administration (NASA) Post-Doctoral Program at the Ames Research Center administered by Universities Space Research Association (USRA) through a contract with NASA. We acknowledge useful exchanges with Mark Gurwell on the ALMA CO observations. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. J.L.O., P.S.-S., N.M. and R.D. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709), they also acknowledge the financial support by the Spanish grant AYA-2017-84637-R and the Proyecto de Excelencia de la Junta de Andalucia J.A. 2012-FQM1776. The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement no. 687378, as part of the project "Small Bodies Near and Far" (SBNAF). P.S.-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 "LEO-SBNAF". The work was partially based on observations made at the Laboratorio Nacional de Astrofisica (LNA), Itajuba-MG, Brazil. The following authors acknowledge the respective CNPq grants: F.B.-R. 309578/2017-5; R.V.-M. 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3 and 305917/2019-6; M.A. 427700/20183, 310683/2017-3, 473002/2013-2. This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brasil (CAPES) -Finance Code 001 and the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant 465376/2014-2). G.B.R. acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 and CAPES-PRINT/UNESP grant 88887.571156/2020-00, M.A. FAPERJ grant E26/111.488/2013 and A.R.G.Jr. FAPESP grant 2018/11239-8. B.E.M. thanks CNPq 150612/2020-6 and CAPES/Cofecub-394/2016-05 grants. Part of the photometric data used in this study were collected in the frame of the photometric observations with the robotic and remotely controlled telescope at the University of Athens Observatory (UOAO; Gazeas 2016). The 2.3 m Aristarchos telescope is operated on Helmos Observatory by the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens. Observations with the 2.3 m Aristarchos telescope were carried out under OPTICON programme. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 730890. This material reflects only the authors views and the Commission is not liable for any use that may be made of the information contained therein. The 1. 2m Kryoneri telescope is operated by the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens. The Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) is managed by the Fondazione Clement Fillietroz-ONLUS, which is supported by the Regional Government of the Aosta Valley, the Town Municipality of Nus and the "Unite des Communes valdotaines Mont-Emilius". The 0.81 m Main Telescope at the OAVdA was upgraded thanks to a Shoemaker NEO Grant 2013 from The Planetary Society. D.C. and J.M.C. acknowledge funds from a 2017 'Research and Education' grant from Fondazione CRT-Cassa di Risparmio di Torino. P.M. acknowledges support from the Portuguese Fundacao para a Ciencia e a Tecnologia ref. PTDC/FISAST/29942/2017 through national funds and by FEDER through COMPETE 2020 (ref. POCI010145 FEDER007672). F.J. acknowledges Jean Luc Plouvier for his help. S.J.F. and C.A. would like to thank the UCL student support observers: Helen Dai, Elise Darragh-Ford, Ross Dobson, Max Hipperson, Edward Kerr-Dineen, Isaac Langley, Emese Meder, Roman Gerasimov, Javier Sanjuan, and Manasvee Saraf. We are grateful to the CAHA, OSN and La Hita Observatory staffs. This research is partially based on observations collected at Centro Astronomico HispanoAleman (CAHA) at Calar Alto, operated jointly by Junta de Andalucia and Consejo Superior de Investigaciones Cientificas (IAA-CSIC). This research was also partially based on observation carried out at the Observatorio de Sierra Nevada (OSN) operated by Instituto de Astrofisica de Andalucia (CSIC). This article is also based on observations made with the Liverpool Telescope operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. Partially based on observations made with the Tx40 and Excalibur telescopes at the Observatorio Astrofisico de Javalambre in Teruel, a Spanish Infraestructura Cientifico-Tecnica Singular (ICTS) owned, managed and operated by the Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA). Tx40 and Excalibur are funded with the Fondos de Inversiones de Teruel (FITE). A.R.R. would like to thank Gustavo Roman for the mechanical adaptation of the camera to the telescope to allow for the observation to be recorded. R.H., J.F.R., S.P.H. and A.S.L. have been supported by the Spanish projects AYA2015-65041P and PID2019-109467GB-100 (MINECO/FEDER, UE) and Grupos Gobierno Vasco IT1366-19. Our great thanks to Omar Hila and their collaborators in Atlas Golf Marrakech Observatory for providing access to the T60cm telescope. TRAPPIST is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant PDR T.0120.21. TRAPPIST-North is a project funded by the University of Liege, and performed in collaboration with Cadi Ayyad University of Marrakesh. E.J. is a FNRS Senior Research Associate., Context. A stellar occultation by Neptune's main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection. Aims. We aimed at constraining Triton's atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis. Methods. We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range similar to 8 km to similar to 190 km, corresponding to pressure levels from 9 mu bar down to a few nanobars. Results. (i) A pressure of 1.18 +/- 0.03 mu bar is found at a reference radius of 1400 km (47 km altitude). (ii) A new analysis of the Voyager 2 radio science occultation shows that this is consistent with an extrapolation of pressure down to the surface pressure obtained in 1989. (iii) A survey of occultations obtained between 1989 and 2017 suggests that an enhancement in surface pressure as reported during the 1990s might be real, but debatable, due to very few high S/N light curves and data accessible for reanalysis. The volatile transport model analysed supports a moderate increase in surface pressure, with a maximum value around 2005-2015 no higher than 23 mu bar. The pressures observed in 1995-1997 and 2017 appear mutually inconsistent with the volatile transport model presented here. (iv) The central flash structure does not show evidence of an atmospheric distortion. We find an upper limit of 0.0011 for the apparent oblateness of the atmosphere near the 8 km altitude., Portuguese Foundation for Science and Technology SFRH/BD/131700/2017, European Social Fund (ESF) SFRH/BD/131700/2017, European Research Council under the European Community's H2020 2014-2021 ERC grant 669416, Spanish Government SEV-2017-0709 AYA-2017-84637-R AYA-RTI2018-098657-J-I00, Junta de Andalucia 2012-FQM1776, European Union's Horizon 2020 Research and Innovation Programme, as part of the project "Small Bodies Near and Far" (SBNAF) 687378, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ), Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF) 309578/2017-5 304544/2017-5 401903/2016-8 308150/2016-3 305917/2019-6 427700/2018-3 310683/2017-3 473002/2013-2, Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) 001, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 465376/2014-2 CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 CAPES-PRINT/UNESP grant 88887.571156/2020-00, Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ) E26/111.488/2013, Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2018/11239-8, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 150612/2020-6, European Union's Horizon 2020 research and innovation programme 730890, Regional Government of the Aosta Valley, Town Municipality of Nus, Unite des Communes valdotaines Mont-Emilius, Planetary Society, Fondazione CRT-Cassa di Risparmio di Torino, Portuguese Foundation for Science and Technology PTDC/FISAST/29942/2017, FEDER through COMPETE 2020 POCI010145 FEDER007672, UK Research & Innovation (UKRI), Science & Technology Facilities Council (STFC), Fondos de Inversiones de Teruel (FITE), Spanish Government AYA2015-65041P PID2019-109467GB-100, Grupos Gobierno Vasco IT1366-19, Fonds de la Recherche Scientifique - FNRS PDR T.0120.21, University of Liege, CAPES/Cofecub-394/2016-05

Published
2022

2. Refined physical parameters for Chariklo’s body and rings from stellar occultations observed between 2013 and 2020

Author

Daniel E. Reichart, Jose Luis Ortiz, Anaëlle Maury, C. Jacques, W. Beisker, M. V. Sieyra, Rodrigo Leiva, L. L. Trabuco, U. G. Jørgensen, J. P. Colque, Michael Backes, R. C. Boufleur, Nicolás Morales, R. Evans, Bruno Sicardy, D. Herald, G. Benedetti-Rossi, E. M. Schneiter, E. Meza, Felipe Braga-Ribas, C. L. Pereira, Josselin Desmars, Othon C. Winter, Jesper Skottfelt, P. Cacella, Colin Snodgrass, L. Maquet, G. Hesler, Tobias C. Hinse, Rafael Sfair, Julio Camargo, P. D. Maley, R. Vieira-Martins, T. Moura, A. R. Gomes-Júnior, C. A. Zuluaga, F. Quispe-Huaynasi, R. A. Artola, C. Erickson, Martin Dominik, M. Starck, T. Linder, K. L. Bath, S. E. Levine, J. F. Soulier, Pablo Santos-Sanz, D. I. Machado, B. L. Giacchini, Joe Pollock, Marcelo Assafin, A. Zapata, S. Bouley, D. Bérard, Emmanuel Jehin, Eduardo Unda-Sanzana, L. S. Amaral, T. de Santana, Vladimir Kouprianov, Marcelo Emilio, Marc W. Buie, A. Amarante, François Colas, W. Hanna, D. Garcia-Lambas, C. Colazo, J. L. Dauvergne, T. A. R. Yamashita, R. C. Poltronieri, Rene Duffard, B. E. Morgado, F. L. Rommel, B. Mondon, P. Thierry, Jeffrey A. Newman, R. Melia, J. Fabrega-Polleri, M. Kretlow, T. Payet, Pascal Torres, Estela Fernández-Valenzuela, S. Kerr, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut Polytechnique des Sciences Avancées (IPSA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidad Politécnica de Madrid (UPM), Utrecht University [Utrecht], CHU Pointe-à-Pitre/Abymes [Guadeloupe], Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), The Salk Institute for Biological Studies, Université Catholique de Louvain (UCL), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, University of Edinburgh, Swedish University of Agricultural Sciences (SLU), CHU Pontchaillou [Rennes], Centre d'Investigation Clinique [Rennes] (CIC), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Hôpital Pontchaillou-Institut National de la Santé et de la Recherche Médicale (INSERM), Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidade do Porto, Unité de Recherche Pluridisciplinaire Sport, Santé, Société (URePSSS) - ULR 7369 - ULR 4488 (URePSSS), Université d'Artois (UA)-Université de Lille-Université du Littoral Côte d'Opale (ULCO), Kyoto University [Kyoto], Airbus Defence and Space [Toulouse], European Research Council, Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), European Commission, National Fund for Scientific Research (Belgium), Fundação de Amparo à Pesquisa do Estado de São Paulo, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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), Association T60, Observatoire Midi-Pyrénées, Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Université Catholique de Louvain = Catholic University of Louvain (UCL), Universidade do Porto = University of Porto, Kyoto University, Université d'Artois (UA)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille, Université du Littoral Côte d'Opale (ULCO), University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
010504 meteorology & atmospheric sciences, Astrophysics, 01 natural sciences, Occultation, individual: Chariklo [asteroids], QB Astronomy, Eccentricity (behavior), data analysis [Methods], 010303 astronomy & astrophysics, QC, media_common, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), CENTAURS, Astrophysics::Instrumentation and Methods for Astrophysics, 3rd-DAS, asteroids: individual: Chariklo, Asteroid, Physical Sciences, SHAPE, Occultations, methods: observational, individual: Chariklo [Minor planets, asteroids], rings [Planets and satellites], Opacity, media_common.quotation_subject, FOS: Physical sciences, Context (language use), Astronomy & Astrophysics, Ephemeris, Minor planets, asteroids: individual: Chariklo, Computer Science::Digital Libraries, planets and satellites: rings, 0103 physical sciences, occultations, TRANS-NEPTUNIAN OBJECTS, observational [Methods], Variation (astronomy), 0105 earth and related environmental sciences, Science & Technology, Astronomy and Astrophysics, URANIAN RINGS, Light curve, methods: data analysis, Physics::History of Physics, QC Physics, SIZE, Space and Planetary Science, minor planets, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], SYSTEM, Astrophysics - Earth and Planetary Astrophysics
Abstract

Full list of authors: Morgado, B. E.; Sicardy, B.; Braga-Ribas, F.; Desmars, J.; Gomes-Júnior, A. R.; Bérard, D.; Leiva, R.; Ortiz, J. L.; Vieira-Martins, R.; Benedetti-Rossi, G.; Santos-Sanz, P.; Camargo, J. I. B.; Duffard, R.; Rommel, F. L.; Assafin, M.; Boufleur, R. C.; Colas, F.; Kretlow, M.; Beisker, W.; Sfair, R.; Snodgrass, C.; Morales, N.; Fernández-Valenzuela, E.; Amaral, L. S.; Amarante, A.; Artola, R. A.; Backes, M.; Bath, K. -L.; Bouley, S.; Buie, M. W.; Cacella, P.; Colazo, C. A.; Colque, J. P.; Dauvergne, J. -L.; Dominik, M.; Emilio, M.; Erickson, C.; Evans, R.; Fabrega-Polleri, J.; Garcia-Lambas, D.; Giacchini, B. L.; Hanna, W.; Herald, D.; Hesler, G.; Hinse, T. C.; Jacques, C.; Jehin, E.; Jørgensen, U. G.; Kerr, S.; Kouprianov, V.; Levine, S. E.; Linder, T.; Maley, P. D.; Machado, D. I.; Maquet, L.; Maury, A.; Melia, R.; Meza, E.; Mondon, B.; Moura, T.; Newman, J.; Payet, T.; Pereira, C. L.; Pollock, J.; Poltronieri, R. C.; Quispe-Huaynasi, F.; Reichart, D.; de Santana, T.; Schneiter, E. M.; Sieyra, M. V.; Skottfelt, J.; Soulier, J. F.; Starck, M.; Thierry, P.; Torres, P. J.; Trabuco, L. L.; Unda-Sanzana, E.; Yamashita, T. A. R.; Winter, O. C.; Zapata, A.; Zuluaga, C. A.--This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Context. The Centaur (10199) Chariklo has the first ring system discovered around a small object. It was first observed using stellar occultation in 2013. Stellar occultations allow sizes and shapes to be determined with kilometre accuracy, and provide the characteristics of the occulting object and its vicinity. Aims. Using stellar occultations observed between 2017 and 2020, our aim is to constrain the physical parameters of Chariklo and its rings. We also determine the structure of the rings, and obtain precise astrometrical positions of Chariklo. Methods. We predicted and organised several observational campaigns of stellar occultations by Chariklo. Occultation light curves were measured from the datasets, from which ingress and egress times, and the ring widths and opacity values were obtained. These measurements, combined with results from previous works, allow us to obtain significant constraints on Chariklo's shape and ring structure. Results. We characterise Chariklo's ring system (C1R and C2R), and obtain radii and pole orientations that are consistent with, but more accurate than, results from previous occultations. We confirm the detection of W-shaped structures within C1R and an evident variation in radial width. The observed width ranges between 4.8 and 9.1 km with a mean value of 6.5 km. One dual observation (visible and red) does not reveal any differences in the C1R opacity profiles, indicating a ring particle size larger than a few microns. The C1R ring eccentricity is found to be smaller than 0.022 (3σ), and its width variations may indicate an eccentricity higher than ~0.005. We fit a tri-axial shape to Chariklo's detections over 11 occultations, and determine that Chariklo is consistent with an ellipsoid with semi-axes of 143.8-1.5+1.4, 135.2-2.8+1.4, and 99.1-2.7+5.4 km. Ultimately, we provided seven astrometric positions at a milliarcsecond accuracy level, based on Gaia EDR3, and use it to improve Chariklo's ephemeris. © B. E. Morgado et al. 2021., This work was carried out within the “Lucky Star” umbrella that agglomerates the efforts of the Paris, Granada and Rio teams, which is funded by the European Research Council under the European Community’s H2020 (ERC Grant Agreement No. 669416). This research made use of SORA, a python package for stellar occultations reduction and analysis, developed with the support of ERC Lucky Star and LIneA/Brazil, within the collaboration Rio-Paris-Granada teams. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Part of this research is suported by INCT do e-Universo, Brazil (CNPQ grants 465376/2014-2). Based in part on observations made at the Laboratório Nacional de Astrofísica (LNA), Itajubá-MG, Brazil. The data include observations taken by the MiNDSTEp team at the Danish 1.54 m telescope at ESO’s La Silla observatory” and “UGJ acknowledges funding from the European Union H2020-MSCA-ITN-2019 under grant no. 860470 (CHAMELEON) and from the Novo Nordisk Foundation Interdisciplinary Synergy Programme grant no. NNF19OC0057374. TRAPPIST-South is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant PDR T.0120.21. The authors acknowledge the use of Sonja Itting-Enke’s C14 telescope and the facilities at the Cuno Hoffmeister Memorial Observatory (CHMO). The following authors acknowledge the respective CNPq grants: BEM 150612/2020-6; FB-R 314772/2020-0; RV-M 304544/2017-f5, 401903/2016-8; JIBC 308150/2016-3 and 305917/2019-6; MA 427700/2018-3, 310683/2017-3, 473002/2013-2. G.B.R. acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 and CAPES-PRINT/UNESP grant 88887.571156/2020-00, MA FAPERJ grant E-26/111.488/2013 and ARGJr FAPESP grant 2018/11239-8. J.L.O., P.S.-S., R.D., and N.M. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), from Spanish project AYA2017-89637-R, and from FEDER. P.S.-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 “LEO-SBNAF” (MCIU/AEI/FEDER, UE). E. Jehin is a Belgian FNRS Senior Research Associate. R.S. and O.C.W. acknowledge FAPESP grant 2016/24561-0 and CNPq grant 305210/2018-1. T.C.H. acknowledges financial support from the National Research Foundation (NRF; No. 2019R1I1A1A01059609).

Published
2021

3. Lower atmosphere and pressure evolution on Pluto from ground-based stellar occultations, 1988–2016

Author

Jean Lecacheux, Michaël Gillon, Jean Manfroid, Josselin Desmars, Robert R. Howell, T. R. Marsh, G. Benedetti-Rossi, J. G. Greenhill, A. Dias-Oliveira, Ilan Manulis, G. Wortmann, K. M. Ivarsen, J.-E. Communal, S. Renner, F. Vachier, L. Tzouganatos, M. Irzyk, P. Machado, M. Harnisch, Lawrence H. Wasserman, J. Broughton, V. Lorenzi, W. H. Allen, W. Beisker, G. Murawsky, A. Magazzu, David Polishook, J. Marques Oliveira, A. R. Gomes-Junior, M. Conti, J. P. Godard, M. Lavayssière, G. Krannich, Lawrence A. Molnar, Federica B. Bianco, S. de Visscher, Leslie A. Young, Maxime Devogele, Marcelo Assafin, Alessandro Marchini, B. Kattentidt, P. Barroy, G. Dangl, A. Eberle, J. B. Haislip, K. M. Hill, Nora Morales, Andrew A. Cole, P. Enskonatus, B. Loader, Emilio Molinari, V. S. Dhillon, O. Klös, M. Ait Moulay Larbi, Bruno Sicardy, Tanguy Bertrand, Richard Querel, K. Walzel, Diane Berard, P. Lindner, J. P. Rivet, Y. Moulane, L. Di Fabrizio, Rene Duffard, D. Vérilhac, G. McKay, Raoul Behrend, Emmanuel Jehin, Fabio Salvaggio, Greg Bolt, Ricardo Gil-Hutton, J. Milner, Martin Jelínek, J. Sérot, D. Vernet, Kosmas Gazeas, F. Signoret, K. L. Bath, A. C. Gilmore, E. Lellouch, D. Herald, A. Selva, D. Lanoiselée, M. Boutet, Ph. Bendjoya, Shai Kaspi, E. Meza, John Talbot, S. P. Littlefair, Alain Maury, Roberto Vieira-Martins, Marc W. Buie, F. Jabet, S. Kerr, A. Román, Thomas Widemann, C. Opitom, R. Zanmar Sanchez, P. B. Graham, E. Frappa, Catherine B. Olkin, H.-J. Bode, H. Eichler, J. De Queiroz, K. Lindner, A. P. LaCluyze, Zouhair Benkhaldoun, D. Gault, Alain Doressoundiram, François Forget, Riccardo Papini, T. Dobosz, B. E. Morgado, J. Rovira, B. Lade, Daniel E. Reichart, O. Faragó, R. Jansen, Luigi Mancini, A. Noschese, Noah Brosch, Felipe Braga-Ribas, A. Daassou, H. Pavlov, A. Carbognani, S. Todd, F. Colas, Y. El Azhari, C. Peterson, V. Tsamis, M. Bretton, J. Hattenbach, F. Ciabattari, Rodrigo Leiva, C. Veillet, A. J. Castro Tirado, Joe Pollock, R. Naves, Pablo Santos-Sanz, D. Hampf, D. Neel, J. L. Ortiz, S. Alonso, L. Abe, P. M. Kilmartin, Julio Camargo, J. M. Ohlert, D. Gloistein, K. Tigani, F. Marchis, M. Dohrmann, Richard G. French, Ronan Cunniffe, T. Janik, Tamás Tordai, E. F. Young, S. Parker, G. Bonnoli, A. Pennell, M. Kretlow, P. Sogorb, Z. Moravec, W. Rothe, C. Perelló, K. Guhl, A. B. Giles, B. Gährken, Françoise Roques, Valentin D. Ivanov, Giuseppe Leto, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Centre Hospitalier Universitaire de Nîmes (CHU Nîmes), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Ludwig Maximilians University of Munich, Southwest Research Institute [Boulder] (SwRI), Observatorio Nacional [Rio de Janeiro], Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP), Observatório Nacional/MCT, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), UZEI PRAGUE CZE, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), National Institute of Water and Atmospheric Research [Lauder] (NIWA), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Department of Physics and Astronomy [Boone], Appalachian State University, University of North Carolina System (UNC)-University of North Carolina System (UNC), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Universidad Nacional de San Juan (UNSJ), University of Sheffield [Sheffield], Kuriwa Observatory, Astronomical Association of Queensland (AAQ), Euraster, Observatoire de Dax, Cardiff School of European Studies (CSES), Cardiff University, Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Fundació Privada Observatori Esteve Duran, The Wise Observatory and The Raymond & Beverly Sackler School of Physics and Astronomy, Tel Aviv University [Tel Aviv], Wise Observatory and Department of geophysics and planetary sciences, Université Cadi Ayyad [Marrakech] (UCA), Stockport Observatory, Occultation Section [Wellington], Royal Astronomical Society of New Zealand, Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Università degli Studi di Perugia (UNIPG), Institut Pascal (IP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Centre National de la Recherche Scientifique (CNRS), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Astronomical Union of Sparta [Sparta], Laboratoire de Physique de la Matière Condensée - UR UPJV 2081 (LPMC), Université de Picardie Jules Verne (UPJV), PEIRENE (PEIRENE), Institut Génomique, Environnement, Immunité, Santé, Thérapeutique (GEIST), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Obervatoire des Baronnies Provençales (OBP), Observatorio Montcabre, Institut Laue-Langevin (ILL), ILL, ITA, USA, GBR, FRA, DEU, ESP, ARG, AUS, AUT, BEL, BRA, CHL, GRC, ISR, MAR, NZL, POL, PRT, CZE, CHE, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Ludwig-Maximilians University [Munich] (LMU), Université de Genève = University of Geneva (UNIGE), Universidad Nacional de San Juan [Argentine] (UNSJ), University of California (UC)-University of California (UC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Tel Aviv University (TAU), Università degli Studi di Perugia = University of Perugia (UNIPG), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Ministerio de Economía y Competitividad (España), European Research Council, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil)

Subjects
planets and satellites: physical evolution, 010504 meteorology & atmospheric sciences, Orbital eccentricity, Context (language use), Surface pressure, Atmospheric sciences, 7. Clean energy, 01 natural sciences, planets and satellites: terrestrial planets, Atmosphere, techniques: photometric, Altitude, Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, methods: observational, methods: data analysis, planets and satellites: atmospheres, observational [Methods], data analysis [Methods], 010303 astronomy & astrophysics, physical evolution [Planets and satellites], Optical depth, 0105 earth and related environmental sciences, methods: observational, methods: data analysis, planets and satellites: atmospheres, techniques: photometric, planets and satellites: physical evolution, planets and satellites: terrestrial planets, Astrophysics - Earth and Planetary Astrophysics, photometric [Techniques], Astronomy and Astrophysics, Albedo, Pluto, 13. Climate action, Space and Planetary Science, terrestrial planets [Planets and satellites], atmospheres [Planets and satellites], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

This article is dedicated to the memory of H.-J. Bode, J. G. Greenhill and O. Faragó for their long-standing support and participation to occultation campaigns. The work leading to these results has received funding from the European Research Council under the European Community’s H2020 2014-2020 ERC Grant Agreement n° 669416 “Lucky Star”. E.M. thanks support from Concytec-Fondecyt-PE and GA, FC-UNI for providing support during the 2012 July 18 occultation. B.S. thanks S. Para for partly supporting this research though a donation, J. P. Beaulieu for helping us accessing to the Hobart Observatory facilities and B. Warner, B. L. Gary, C. Erickson, H. Reitsema, L. Albert, P. J. Merritt, T. Hall, W. J. Romanishin, Y. J. Choi for providing data during the 2007 March 18 occultation. M.A. thanks CNPq (Grants 427700/2018-3, 310683/2017-3 and 473002/2013-2) and FAPERJ (Grant E-26/111.488/2013). J.L.O. thanks support from grant AYA2017-89637-R. P.S.S. acknowledges financial support from the European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378, as part of the project “Small Bodies Near and Far” (SBNAF). J.L.O., R.D., P.S.S. and N.M. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). F.B.R. acknowledges CNPq support process 309578/2017-5. G.B.R. thanks support from the grant CAPES-FAPERJ/PAPDRJ (E26/203.173/2016). J.I.B.C. acknowledges CNPq grant 308150/2016-3. R.V.M. thanks the grants: CNPq-304544/2017-5, 401903/2016-8, and Faperj: PAPDRJ-45/2013 and E-26/203.026/2015. B.M. thanks the CAPES/Cofecub-394/2016-05 grant and CAPES/Brazil – Finance Code 001. B.M. and A.R.G.J. were financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) – Finance Code 001. TRAPPIST-North is a project funded by the University of Liège, in collaboration with Cadi Ayyad University of Marrakech (Morocco). TRAPPIST-South is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Foundation (FNS/SNSF). VSD, SPL, TRM and ULTRACAM are all supported by the STFC. K.G. acknowledges help from the team of Archenhold-Observatory, Berlin, and A.R. thanks G. Román (Granada) for help during the observation of the 2016 July 19 occultation. A.J.C.T. acknowledges support from the Spanish Ministry Project AYA2015-71718-R (including EU funds). We thank Caisey Harlingten for the repeated use of his 50 cm telescopes in San Pedro de Atacama, Chile. We thank the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. L.M. acknowledges support from the Italian Minister of Instruction, University and Research (MIUR) through FFABR 2017 fund and support from the University of Rome Tor Vergata through “Mission: Sustainability 2016” fund. The Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) is managed by the Fondazione Clément Fillietroz-ONLUS, which is supported by the Regional Governmentof the Aosta Valley, the Town Municipality of Nus and the “Unité des Communes valdôtaines Mont-Émilius”. The research was partially funded by a 2016 “Research and Education”s grant from Fondazione CRT. We thank D.P. Hinson for his constructive and detailed comments that helped to improve this article., Context. The tenuous nitrogen (N2) atmosphere on Pluto undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has recently (July 2015) been observed by the New Horizons spacecraft. Aims. The main goals of this study are (i) to construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) to constrain the structure of the lower atmosphere using a central flash observed in 2015. Methods. Eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between altitude levels of ~5 and ~380 km (i.e. pressures from ~ 10 μbar to 10 nbar). Results. (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived. (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia; and/or (b) hazes with tangential optical depth of ~0.3 are present at 4–7 km altitude levels; and/or (c) the nominal REX density values are overestimated by an implausibly large factor of ~20%; and/or (d) higher terrains block part of the flash in the Charon facing hemisphere., European Research Council under the European Community’s H2020 2014-2020 ERC Grant Agreement n° 669416 “Lucky Star”, Grants 427700/2018-3, 310683/2017-3 and 473002/2013-2) and FAPERJ (Grant E-26/111.488/2013), Grant AYA2017-89637-R. P.S.S. acknowledges financial support from the European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378, as part of the project “Small Bodies Near and Far” (SBNAF), Financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709), Support process 309578/2017-5. G.B.R. thanks support from the grant CAPES-FAPERJ/PAPDRJ (E26/203.173/2016). J.I.B.C. acknowledges CNPq grant 308150/2016-3. R.V.M. thanks the grants: CNPq-304544/2017-5, 401903/2016-8, and Faperj: PAPDRJ-45/2013 and E-26/203.026/2015. B.M. thanks the CAPES/Cofecub-394/2016-05 grant and CAPES/Brazil – Finance Code 001., Grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Foundation (FNS/SNSF), Support from the Spanish Ministry Project AYA2015-71718-R (including EU funds), Support from the Italian Minister of Instruction, University and Research (MIUR) through FFABR 2017 fund and support from the University of Rome Tor Vergata through “Mission: Sustainability 2016” fund

Published
2019

4. Size and Shape of Chariklo from Multi-epoch Stellar Occultations

Author

R. Vieira-Martins, Amanda A. Sickafoose, H. Breytenbach, K.-L. Bath, Rene Duffard, Bruno Sicardy, Pierre Kervella, C. De Witt, B. Lade, S. Kerr, D. Bérard, A. Cool, L. Maquet, P. Schoenau, Jose L. Ortiz, G. Benedetti-Rossi, Felipe Braga-Ribas, François Colas, H.-J. Bode, Marcelo Assafin, D. Herald, Nicolás Morales, B. E. Morgado, Josselin Desmars, Julio Camargo, E. Meza, A. R. Gomes-Júnior, Emmanuel Lellouch, J.-L. Dauvergne, Rodrigo Leiva, Colin Snodgrass, 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), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatorio Nacional [Rio de Janeiro], Observatório Nacional/MCT, Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), L2EP - Équipe Réseaux, Laboratoire d’Électrotechnique et d’Électronique de Puissance - ULR 2697 (L2EP), Centrale Lille-Haute Etude d'Ingénieurs-Université de Lille-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Centrale Lille-Haute Etude d'Ingénieurs-Université de Lille-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), Springbok, Stockport Observatory, Astronomical Association of Queensland (AAQ), Canberra Astronomical Society, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Universidade Federal do Rio de Janeiro [Rio de Janeiro] (UFRJ), Laboratoire d’Électrotechnique et d’Électronique de Puissance - EA 2697 (L2EP), Ecole Centrale de Lille-École Nationale Supérieure d'Arts et Métiers (ENSAM), Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Haute Etude d'Ingénieurs-Université de Lille-Ecole Centrale de Lille-École Nationale Supérieure d'Arts et Métiers (ENSAM), and HESAM Université (HESAM)-HESAM Université (HESAM)-Haute Etude d'Ingénieurs-Université de Lille

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Rotation period, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, Light curve, 01 natural sciences, Ellipsoid, Photometry (optics), Spherical model, Mean motion, 13. Climate action, Space and Planetary Science, Geometric albedo, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

We use data from five stellar occultations observed between 2013 and 2016 to constrain Chariklo's size and shape, and the ring reflectivity. We consider four possible models for Chariklo (sphere, Maclaurin spheroid, tri-axial ellipsoid and Jacobi ellipsoid) and we use a Bayesian approach to estimate the corresponding parameters. The spherical model has a radius $R=129\pm3$ km. The Maclaurin model has equatorial and polar radii $a=b=143^{+3}_{-6}$ km and $c=96^{+14}_{-4}$ km, respectively, with density $970^{+300}_{-180}$ kg m$^{-3}$. The ellipsoidal model has semiaxes $a=148^{+6}_{-4}$ km, $b=132^{+6}_{-5}$ km and $c=102^{+10}_{-8}$ km. Finally, the Jacobi model has semiaxes $a$=157$\pm$4 km, $b$=139$\pm$ 4 km and $c$=86$\pm$1 km, and density $796^{+2}_{-4}$ kg m$^{-3}$ . Depending on the model, we obtain topographic features of 6-11 km, typical of Saturn icy satellites with similar size and density. We constrain Chariklo's geometric albedo between 3.1\% (sphere) and 4.9\% (ellipsoid), while the ring $I/F$ reflectivity is less constrained between 0.6\% (Jacobi) and 8.9\% (sphere). The ellipsoid model explains both the optical light curve and the long-term photometry variation of the system, giving a plausible value for the geometric albedo of the ring particles of $10-15\%$. The derived Chariklo's mass of 6-8$\times10^{18}$ kg places the rings close to the 3:1 resonance between the ring mean motion and Chariklo's rotation period., Comment: Accepted for publication in AJ

Published
2017

5. The two Titan stellar occultations of 14 November 2003

Author

M. Kidger, H. Lüdemann, B. Thomé, F. Bode, Daisuke Baba, C. Martinez, François Colas, C. Tegtmeier, D. Fiel, Jean Lecacheux, Takahiro Nagayama, M. Kretlow, P. Schoenau, T. Payet, Françoise Roques, S. Renner, Brian Fraser, Ian S. Glass, M. Rapaport, H. J. Bode, D. Neubauer, M. Hernandez, P. Meintjies, J. P. Teng, Robert R. Howell, C. Turk, S. Lacour, W. Beisker, F. Hund, C. Etienne, O. Naranjo, Bruno Sicardy, Tetsuya Nagata, Thomas Widemann, A. Bellucci, Terry J. Jones, Francesca Ferri, K.-L. Bath, E. Frappa, S. Itting-Enke, J. Lüdemann, A. Jansen, Agnes Fienga, Emmanuel Lellouch, A. Tegtmeier, G. Hesler, J. L. Ortiz, S. Pau, P. Rosenzweig, A. Peyrot, M. Vignand, C. DeWitt, 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 Astronomie du 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Ingénieurs, Techniciens et Administratifs, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), International Occultation Timing Association, European Section (IOTA/ES), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Observatoire de Paris, Université Paris sciences et lettres (PSL), Instituto Superior de Ciencias Astronómicas, South African Astronomical Observatory (SAAO), Department of Astrophysics, Nagoya University, Windhoek, Hakos Guestfarm, Astronomical Society of Southern Africa, Boyden Observatory, University of the Free State, Association des Utilisateurs de Détecteurs Electroniques (AUDE), Association des Utilisateurs de Détecteurs Electroniques, Lycée Stanislas, Paris, Astronef-Planétarium de Saint-Etienne, Observatoire astronomique des Makes, Association Réunionnaise pour l'Etude du Ciel Austral (ARECA), Wyoming InfraRed Observatory, Department of Physics and Astronomy, Instituto de Astrofísica de Canarias (IAC), Instituto de Astrofisica de Andalucia, CSIC (IAA), Universidad de Los Andes, Facultad de Ciencias, Departamento de Física, Grupo de Astrofísica Teórica, Observatoire aquitain des sciences de l'univers (OASU), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, Haze, Equator, Soil Science, Aquatic Science, Oceanography, Atmospheric sciences, Latitude, symbols.namesake, Altitude, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Southern Hemisphere, Stratosphere, Earth-Surface Processes, Water Science and Technology, Ecology, Paleontology, Forestry, Light curve, Geophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], symbols, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract

[1] We report the observation of two stellar occultations by Titan on 14 November 2003, using stations in the Indian Ocean, southern Africa, Spain, and northern and southern Americas. These occultations probed altitudes between ∼550 and 250 km (∼1 to 250 μbar) in Titan's upper stratosphere. The light curves reveal a sharp inversion layer near 515 ± 6 km altitude (1.5 μbar pressure level), where the temperature increases by 15 K in only 6 km. This layer is close to an inversion layer observed fourteen months later by the Huygens HASI instrument during the entry of the probe in Titan's atmosphere on 14 January 2005 [Fulchignoni et al., 2005]. Central flashes observed during the first occultation provide constraints on the zonal wind regime at 250 km, with a strong northern jet (∼200 m s -1 ) around the latitude 55°N, wind velocities of ∼150 m s -1 near the equator, and progressively weaker winds as more southern latitudes are probed. The haze distribution around Titan's limb at 250 km altitude is close to that predicted by the Global Circulation Model of Rannou et al. (2004) in the southern hemisphere, but a clearing north of 40°N is necessary to explain our data. This contrasts with Rannou et al.'s (2004) model, which predicts a very thick polar hood over Titan's northern polar regions. Simultaneous observations of the flashes at various wavelengths provide a dependence of τ ∝ λ -q , with q = 1.8 ± 0.5 between 0.51 and 2.2 μm for the tangential optical depth of the hazes at 250 km altitude.

Published
2006

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