Author: "Felipe Braga Ribas" / Language: english - Searchworks@Jio Institute Digital Library Search Results

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1. Pluto's Atmosphere in Plateau Phase Since 2015 from a Stellar Occultation at Devasthal

Author: Bruno Sicardy, Nagarhalli M. Ashok, Anandmayee Tej, Ganesh Pawar, Shishir Deshmukh, Ameya Deshpande, Saurabh Sharma, Josselin Desmars, Marcelo Assafin, Jose Luis Ortiz, Gustavo Benedetti-Rossi, Felipe Braga-Ribas, Roberto Vieira-Martins, Pablo Santos-Sanz, Krishan Chand, Bhuwan C. Bhatt, European Research Council, European Commission, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), 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 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 de Paris, Physical Research Laboratory, Indian Institute of Space Science and Technology, Akashmitra Mandal, Aryabhatta Research Institute of Observational Sciences, Institut Polytechnique des Sciences Avancées IPSA, Univ. Lille, Universidade Federal do Rio de Janeiro (UFRJ), Laboratório Interinstitucional de e-Astronomia - LIneA, IAA-CSIC, Universidade Estadual Paulista (UNESP), Federal University of Technology-Paraná (UTFPR / DAFIS), Observatório Nacional/MCTIC, and Indian Institute of Astrophysics
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), [SDU]Sciences of the Universe [physics], Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Astrophysics - Earth and Planetary Astrophysics
Abstract: This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., A stellar occultation by Pluto was observed on 2020 June 6 with the 1.3 m and 3.6 m telescopes located at Devasthal, Nainital, India, using imaging systems in the I and H bands, respectively. From this event, we derive a surface pressure for Pluto's atmosphere of psurf=12.23-0.38+0.65 μbar. This shows that Pluto's atmosphere has been in a plateau phase since mid-2015, a result which is in excellent agreement with the Pluto volatile transport model of Meza et al. This value does not support the pressure decrease reported by independent teams, based on occultations observed in 2018 and 2019 by Young et al. and Arimatsu et al., respectively. © 2021. The Author(s). Published by the American Astronomical Society., The authors are grateful to the Directors of ARIES and IIA for granting time under Directors' Discretionary Time allotment for observing this event. The authors also thank the staff of the Devasthal Observatory and the IR Group at TIFR for their help during observations. 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 no. 669416 "Lucky Star." Research at PRL and IIST is supported by the Department of Space, Government of India. M.A., G.B.-R., F.B.-R., and R.V.-M. thank CNPq and CAPES for grants 313144/2020-6, 314772/2020-0, 465376/2014-2, and Process 88887.310463/2018-00—Project 88887.571156/2020-00. R.V.-M. also thanks grant CNPq 304544/2017-6. P.S-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 "LEO-SBNAF" (MCIU/AEI/FEDER, UE)., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.
Published: 2021

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. Physical characterization of double asteroid (617) Patroclus from 2007/2012 mutual events observations

Author: F. Colas, Florent Deleflie, Felipe Braga-Ribas, J. Normand, Hiromi Hamanowa, Alain Klotz, Pascal Descamps, P. Vingerhoets, J. A. Farrell, L. Maquet, K. Archer, G. Dubos, Vishnu Reddy, T. Pauwels, Frédéric Vachier, A. Peyrot, Joe Pollock, F. Marchis, A. Leroy, Pedro V. Sada, Jérôme Berthier, Sylvain Bouley, J.-P. Teng-Chuen-Yu, 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), Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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), and 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
Subjects: Physics, Ecliptic coordinate system, 010504 meteorology & atmospheric sciences, Rotation, Surfaces - satellites of asteroids - eclipses - photometry, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Astrometry, Astrophysics, Light curve, 01 natural sciences, Asteroids, Jupiter, Amplitude, Space and Planetary Science, Asteroid, Trojan, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Eclipse
Abstract: International audience; We publish a set of 16 light curves of mutual events inside the synchronous system of the Jupiter Trojan (617) Patroclus. Patroclus is th only binary system of the six target asteroids of the forthcoming NASA Discovery-class mission Lucy. Determining the physical parameters of the system is therefore of primary importance in helping to plan the flyby mission.Light curves were acquired during two follow-up campaigns of 6 months each between January-June 2007 and July-December 2012. Eight small eclipse events of amplitude of 0.2-0.3 mag were recorded in 2007. On the other hand, in 2012, the amplitudes of the phenomena were much deeper, between 0.6 and 0.8 mag, due to a nearly edge-on configuration of the system.We refined the sidereal period to 102.78624 ± 0.00015h = 4.282760 ± 0.000005days. The J2000 ecliptic coordinates of the pole of the system were found to be λ = 235.3 ± 1.2° andβ = - 62.4 ± 0.2°. The volume ratio was determined equal to q = 0.69 ± 0.08. By using a model of inhomogeneous Roche ellipsoids in hydrostatic equilibrium, we derived a bulk density of 0.81 ± 0.16g/cm3 and a surface grain density of 2.69 ± 0.36g/cm3 in agreement with spectroscopic observations of this P-type asteroid.As a validation, our solution was applied to revisit recent results obtained from observations of another type: AO astrometry and stellar occultation. Our model is thus perfectly able to account for these observations after fitting the mutual separation to the value of 695 ± 10km. Consequently, the area-equivalent diameter of the system as a whole is derived DΑ = 168.8 ± 2.6km.
Published: 2020

4. Stellar occultations enable milliarcsecond astrometry for Trans-Neptunian objects and Centaurs

Author: Josselin Desmars, A. Burtovoi, H. Mikuž, J. R. de Barros, Emmanuel Jehin, Marcelo Assafin, J. Fabrega Polleri, S. Sposetti, D. Herald, R. Szakats, A. R. Gomes-Júnior, Bruno Sicardy, D. W. Dunham, H. Tomioka, A. Ossola, Domenico Nardiello, F. L. Rommel, C. L. Pereira, A. Stechina, T. Hayamizu, Sohrab Rahvar, P. Sogorb, R. Vieira-Martins, Jose Luis Ortiz, Julio Camargo, J. B. Dunham, Luca Zampieri, P. Pravec, R. Komžík, J. Broughton, T. Janik, Anaëlle Maury, B. E. Morgado, P. M. Kilmartin, Pablo Santos-Sanz, G. Benedetti-Rossi, K. Hosoi, Rafael Sfair, Othon C. Winter, Nicolás Morales, D. Gault, András Pál, Y. Ueno, J. Tregloan-Reed, A. C. Gilmore, T. Carruthers, Estela Fernández-Valenzuela, P. B. Siqueira, J. Lecacheux, W. Hanna, Rhian H. Jones, Michele Fiori, Jeffrey A. Newman, Valerio Nascimbeni, Jonathan Bradshaw, K. Kitazaki, E. Pimentel, Rene Duffard, Felipe Braga-Ribas, Jan Maarten Winkel, S. Kerr, P. Nosworthy, A. Marciniak, D. Hooper, Giampiero Naletto, C. Jacques, Kamil Hornoch, Colin Snodgrass, Joseph Brimacombe, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Fundação de Amparo à Pesquisa do Estado de São Paulo, Centre National D'Etudes Spatiales (France), National Research, Development and Innovation Office (Hungary), European Research Council, Fonds de la Recherche Scientifique (Fédération Wallonie-Bruxelles), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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), Bairro Imperial de São Cristóvão, Federal University of Technology-Paraná (UTFPR/DAFIS), Institut Polytechnique des Sciences Avancées Ipsa, Univ. Lille, IAA-CSIC, Sorbonne Paris Cité, Universidade Federal do Rio de Janeiro (UFRJ), University of Central Florida, Universidade Estadual Paulista (Unesp), International Occultation Timing Association (IOTA), Trans-Tasman Occultation Alliance (TTOA), Canberra Astronomical Society, Samford Valley Observatory (Q79), Coral Towers Observatory, University of Padova, INAF-Astronomical Observatory of Padova, Jewel Box Observatory, Sonear Observatory, University of Canterbury, Academy of Sciences of the Czech Republic, Astronomical Association of Queensland, Lam, Swiss Astronomical Society, Research Centre for Astronomy and Earth Sciences, Eötvös Loránd University, Institute of Physics, Centro de Amigos de la Astronomia Reconquista-CAAR, Japan Occultation Information Network (JOIN), Reedy Creek Observatory, Université de Liège, Slovak Academy of Sciences, Adam Mickiewicz University, San Pedro de Atacama Celestial Explorations-SPACE, Faculty of Mathematics and Physics, Panamanian Observatory in San Pedro de Atacama-OPSPA, Sharif University of Technology, Royal Observatory, Club d'Astronomie Luberon Sud Astro, and Universidad de Antofagasta
Subjects: 010504 meteorology & atmospheric sciences, general [Minor planets, asteroids], FOS: Physical sciences, Context (language use), Astrophysics, Ephemeris, 01 natural sciences, 0103 physical sciences, Trans-Neptunian object, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Earth and Planetary Astrophysics (astro-ph.EP), International Celestial Reference System, Astrometry, Kuiper belt: general, Minor planets, asteroids: general, Occultations, Minor planets, general [Kuiper belt], Astronomy and Astrophysics, Planetary system, asteroids: general, Space and Planetary Science, Asteroid, astro-ph.EP, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, astro-ph.IM, Reference frame
Abstract: Full list of authors: Rommel, F. L.; Braga-Ribas, F.; Desmars, J.; Camargo, J. I. B.; Ortiz, J. L.; Sicardy, B.; Vieira-Martins, R.; Assafin, M.; Santos-Sanz, P.; Duffard, R.; Fernández-Valenzuela, E.; Lecacheux, J.; Morgado, B. E.; Benedetti-Rossi, G.; Gomes-Júnior, A. R.; Pereira, C. L.; Herald, D.; Hanna, W.; Bradshaw, J.; Morales, N. Brimacombe, J.; Burtovoi, A.; Carruthers, T.; de Barros, J. R.; Fiori, M.; Gilmore, A.; Hooper, D.; Hornoch, K.; Jacques, C.; Janik, T.; Kerr, S.; Kilmartin, P.; Winkel, Jan Maarten; Naletto, G.; Nardiello, D.; Nascimbeni, V.; Newman, J.; Ossola, A.; Pál, A.; Pimentel, E.; Pravec, P.; Sposetti, S.; Stechina, A.; Szakáts, R.; Ueno, Y.; Zampieri, L.; Broughton, J.; Dunham, J. B.; Dunham, D. W.; Gault, D.; Hayamizu, T.; Hosoi, K.; Jehin, E.; Jones, R.; Kitazaki, K.; Komžík, R.; Marciniak, A.; Maury, A.; Mikuž, H.; Nosworthy, P.; Fábrega Polleri, J.; Rahvar, S.; Sfair, R.; Siqueira, P. B.; Snodgrass, C.; Sogorb, P.; Tomioka, H.; Tregloan-Reed, J.; Winter, O. C., Context. Trans-Neptunian objects (TNOs) and Centaurs are remnants of our planetary system formation, and their physical properties have invaluable information for evolutionary theories. Stellar occultation is a ground-based method for studying these distant small bodies and has presented exciting results. These observations can provide precise profiles of the involved body, allowing an accurate determination of its size and shape. Aims. The goal is to show that even single-chord detections of TNOs allow us to measure their milliarcsecond astrometric positions in the reference frame of the Gaia second data release (DR2). Accurate ephemerides can then be generated, allowing predictions of stellar occultations with much higher reliability. Methods. We analyzed data from various stellar occultation detections to obtain astrometric positions of the involved bodies. The events published before the Gaia era were updated so that the Gaia DR2 stellar catalog is the reference, thus providing accurate positions. Events with detection from one or two different sites (single or double chord) were analyzed to determine the event duration. Previously determined sizes were used to calculate the position of the object center and its corresponding error with respectto the detected chord and the International Celestial Reference System propagated Gaia DR2 star position. Results. We derive 37 precise astrometric positions for 19 TNOs and four Centaurs. Twenty-one of these events are presented here for the first time. Although about 68% of our results are based on single-chord detection, most have intrinsic precision at the submilliarcsecond level. Lower limits on the diameter of bodies such as Sedna, 2002 KX14, and Echeclus, and also shape constraints on 2002 VE95, 2003 FF128, and 2005 TV189 are presented as valuable byproducts. Conclusions. Using the Gaia DR2 catalog, we show that even a single detection of a stellar occultation allows improving the object ephemeris significantly, which in turn enables predicting a future stellar occultation with high accuracy. Observational campaigns can be efficiently organized with this help, and may provide a full physical characterization of the involved object, or even the study of topographic features such as satellites or rings. © 2020 ESO., 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). 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; M.A. 427700/2018-3, 310683/2017-3, 473002/2013-2; O.C.W. 305210/2018-1. The following authors acknowledge the respective grants: B.E.M. thanks the CAPES/Cofecub-394/2016-05 grant; G.B-R. acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016; M.A. acknowledges FAPERJ grant E-26/111.488/2013; A.R.G.Jr acknowledges FAPESP grant 2018/11239-8; O.C.W. and R.S. acknowledge FAPESP grant 2016/24561-0. D.N. acknowledges support from the French Centre National d'Etudes Spatiales (CNES). K.H. and P.P. were supported by the project R.V.O.: 67985815. A.P. and R.S. received support from the K-125015 grant of the National Research, Development and Innovation Office (NKFIH, Hungary). Partial funding of the computational infrastructure and database servers are received from the grant KEP-7/2018 of the Hungarian Academy of Sciences. Some of the results were based on observations taken at the 1.6m telescope on Pico dos Dias Observatory of the National Laboratory of Astrophysics (LNA/Brazil). Some data are based on observations collected at the Copernicus and Schmidt telescopes (Asiago, Italy) of the INAF-Astronomical Observatory of Padova. 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 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. TRAPPIST is a project funded by the Belgian FNRS under grant FRFC 2.5.594.09.F and the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. E.J. is a FNRS Senior Research Associate. We would like to acknowledge financial support by the Spanish grant AYA-RTI2018-098657-JI00 "LEO-SBNAF" (MCIU/AEI/FEDER, U.E.) and the financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). Also, AYA2017-89637-R and FEDER funds are acknowledged. We are thankful to the following observers who participated and provided data for respective events as listed in Table B.1: Orlando A. Naranjo from Universidad de Los Andes, Merida/VEN; Faustino Organero from La Hita Observatory - Toledo/ESP.
Published: 2020

5. Volatile evolution and atmospheres of Trans-Neptunian Objects

Author: Felipe Braga-Ribas, Leslie A. Young, and Robert E. Johnson
Subjects: Observational database, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, FOS: Physical sciences, 01 natural sciences, Astrobiology, High surface, Pluto, Physics - Atmospheric and Oceanic Physics, 13. Climate action, 0103 physical sciences, Atmospheric and Oceanic Physics (physics.ao-ph), Environmental science, Stellar occultation, Sublimation (phase transition), Trans-Neptunian object, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: At 30-50 K, the temperatures typical for surfaces in the Kuiper Belt (e.g. Stern & Trafton 2008), only seven species have sublimation pressures higher than 1 nbar (Fray & Schmitt 2009): Ne, N$_2$, CO, Ar, O$_2$, CH$_4$, and Kr. Of these, N$_2$, CO, and CH$_4$ have been detected or inferred on the surfaces of Trans-Neptunian Objects (TNOs). The presence of tenuous atmospheres above these volatile ices depends on the sublimation pressures, which are very sensitive to the composition, temperatures, and mixing states of the volatile ices. Therefore, the retention of volatiles on a TNO is related to its formation environment and thermal history. The surface volatiles may be transported via seasonally varying atmospheres and their condensation might be responsible for the high surface albedos of some of these bodies. The most sensitive searches for tenuous atmospheres are made by the method of stellar occultation, which have been vital for the study of the atmospheres of Triton and Pluto, and has to-date placed upper limits on the atmospheres of 11 other bodies. The recent release of the Gaia astrometric catalog has led to a "golden age" in the ability to predict TNO occultations in order to increase the observational data base.
Published: 2020

6. The 2014-2015 Brazilian Mutual Phenomena campaign for the Jovian satellites and improved results for the 2009 events

Author: R. Vieira-Martins, A. Dias-Oliveira, L. A. G. Boldrin, J. O. Miranda, D. I. Machado, Felipe Braga-Ribas, Marcelo Assafin, M. Malacarne, Othon C. Winter, Rafael Sfair, L. L. Trabuco, T. de Santana, H. S. Gaspar, Julio Camargo, A. R. Gomes-Junior, G. Benedetti-Rossi, B. C. B. Camargo, B. E. Morgado, Observatório Nacional/MCTIC, Laboratório Interinstitucional de e-Astronomia - LIneA and INCT do e-Universo, Universidade Federal do Rio de Janeiro (UFRJ), Escola SESC de Ensino Médio, Universidade Estadual do Oeste do Paraná (Unioeste), Polo Astronômico Casimiro Montenegro Filho/FPTI-BR, Universidade Federal do Espírito Santo (UFES), Universidade Estadual Paulista (Unesp), and Federal University of Technology - Paraná (UTFPR/DAFIS)
Subjects: 010504 meteorology & atmospheric sciences, Amalthea, FOS: Physical sciences, Ephemeris, 01 natural sciences, Jupiter, symbols.namesake, Ganymede, 0103 physical sciences, data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Eclipse, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Callisto, Astronomy, Astronomy and Astrophysics, Astrometry, Light curve, Galilean moons, individual: Io [Planets and satellites], Space and Planetary Science, symbols, Natural satellite, Satellite, Europa, Astrophysics - Earth and Planetary Astrophysics
Abstract: Progress in astrometry and orbital modelling of planetary moons in the last decade enabled better determinations of their orbits. These studies need accurate positions spread over extended periods. We present the results of the 2014-2015 Brazilian campaign for 40 mutual events from 47 observed light curves by the Galilean satellites plus one eclipse of Amalthea by Ganymede. We also reanalysed and updated results for 25 mutual events observed in the 2009 campaign. All telescopes were equipped with narrow-band filters centred at 889 nm with a width of 15 nm to eliminate the scattered light from Jupiter. The albedos' ratio was determined using images before and after each event. We simulated images of moons, umbra, and penumbra in the sky plane, and integrated their fluxes to compute albedos, simulate light curves and fit them to the observed ones using a chi-square fitting procedure. For that, we used the complete version of the Oren-Nayer reflectance model. The relative satellite positions mean uncertainty was 11.2 mas ($\sim$35 km) and 10.1 mas ($\sim$31 km) for the 2014-2015 and 2009 campaigns respectively. The simulated and observed \textsc{ascii} light curve files are freely available in electronic form at the \textit{Natural Satellites DataBase} (NSDB). The 40/25 mutual events from our 2014-2015/2009 campaigns represent a significant contribution of 17%/15% in comparison with the PHEMU campaigns lead by the IMCCE. Besides that, our result for the eclipse of Amalthea is only the 4$^{th}$ such measurement ever published after the three ones observed by the 2014-2015 international PHEMU campaign. Our results are suitable for new orbital/ephemeris determinations for the Galilean moons and Amalthea., 14 pages, 8 figures and 5 tables
Published: 2019

7. First stellar occultation by the Galilean moon Europa and upcoming events between 2019 and 2021

Author: Marcelo Assafin, G. Y. Navas, J. R. de Barros, R. C. Boufleur, P. Cacella, C. Jaques, T. de Santana, Felipe Braga-Ribas, Julio Camargo, F. L. Rommel, Alain Maury, Othon C. Winter, E. Pimentel, L. L. Trabuco, Rafael Sfair, A. Crispim, G. Benedetti-Rossi, William Schoenell, R. Vieira-Martins, D. I. Machado, J. Fabrega, B. E. Morgado, Valery Lainey, A. R. Gomes-Júnior, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), 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 Nacional/MCTIC, Laboratório Interinstitucional de e-Astronomia-LIneA and INCT do e-Universo, Universidade Federal do Rio de Janeiro (UFRJ), Universidade Estadual Paulista (Unesp), California Institute of Technology, Sorbonne Universités, Federal University of Technology-Paraná (UTFPR/DAFIS), Univ. Paris Diderot, San Pedro de Atacama Celestial Explorations, Unioeste, Polo Astronômico Casimiro Montenegro Filho/FPTI-BR, Observatório SONEAR, SMPW, Research Center of Astronomy, and Instituto de Física/UFRGS
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Context (language use), Astrophysics, individual: Europa [Planets and satellites], 01 natural sciences, Galilean, methods, Jupiter, symbols.namesake, Primary (astronomy), 0103 physical sciences, observational [Methods], individual, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, photometric [Techniques], Observational techniques, observational -techniques, Astronomy and Astrophysics, Galactic plane, photometric -occultations -planets and satellites, Galilean moons, Stars, 13. Climate action, Space and Planetary Science, symbols, Occultations, Europa, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. Bright stellar positions are now known with an uncertainty below 1 mas thanks to Gaia DR2. Between 2019-2020, the Galactic plane will be the background of Jupiter. The dense stellar background will lead to an increase in the number of occultations, while the Gaia DR2 catalogue will reduce the prediction uncertainties for the shadow path. Aims. We observed a stellar occultation by the Galilean moon Europa (J2) and propose a campaign for observing stellar occultations for all Galilean moons. Methods. During a predicted period of time, we measured the light flux of the occulted star and the object to determine the time when the flux dropped with respect to one or more reference stars, and the time that it rose again for each observational station. The chords obtained from these observations allowed us to determine apparent sizes, oblatness, and positions with kilometre accuracy. Results. We present results obtained from the first stellar occultation by the Galilean moon Europa observed on 2017 March 31. The apparent fitted ellipse presents an equivalent radius of 1561.2 $\pm$ 3.6 km and oblatenesses 0.0010 $\pm$ 0.0028. A very precise Europa position was determined with an uncertainty of 0.8 mas. We also present prospects for a campaign to observe the future events that will occur between 2019 and 2021 for all Galilean moons. Conclusions. Stellar occultation is a suitable technique for obtaining physical parameters and highly accurate positions of bright satellites close to their primary. A number of successful events can render the 3D shapes of the Galilean moons with high accuracy. We encourage the observational community (amateurs included) to observe the future predicted events., Comment: 10 pages, 16 figures, 4 tables, A&A Letter doi:10.1051/0004-6361/201935500
Published: 2019

8. 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

9. Astrometry and Occultation predictions to Trans-Neptunian and Centaur Objects observed within the Dark Energy Survey

Author: V. Scarpine, Juan de Vicente, Marcelo Assafin, J. Carretero, Flavia Sobreira, Alex Drlica Wagner, S. Serrano, Nikolay Kuropatkin, E. Suchyta, Tim Abbot, Mathew Smith, I. Sevilla, Aurelio Carnero Rossell, Rodney S. Gomes, Josh Frieman, A. A. Plazas, G. Gutierrez, Josselin Desmars, Julio Camargo, Enrique Gaztanaga, Roberto Vieira-Martins, M. A. G. Maia, Juan Garcia-Bellido, Matias Carrasco Kind, Ramon Miquel, E. Buckley-Geer, Luiz N. da Costa, Emmanuel Bertin, Ricardo L. C. Ogando, D. L. Burke, Michael Schubnell, David J. James, David J. Brooks, J. Gschwend, S. Avila, Gary Bernstein, S. Allam, Robert A. Gruendl, Matheus Gysi, Felipe Menanteau, Pablo Fosalba, Molly E. C. Swanson, Christopher J. Davis, Will G. Hartley, Marcelle Soares-Santos, Devon L. Hollowood, Martin Banda-Huarca, Filipe B. Abdalla, Gregory Tarle, Daniel Gruen, Felipe Braga Ribas, D. W. Gerdes, Peter Doel, Thomas Diehl, K. Honscheid, Christopher J. Miller, S. Hamilton, William Wester, Kyler Kuehn, Carlos E. Cunha, E. J. Sanchez, K. Romer, 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), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DES, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, FOS: Physical sciences, Large Synoptic Survey Telescope, 01 natural sciences, Occultation, surveys, 0103 physical sciences, occultations, ephemerides, 010303 astronomy & astrophysics, QC, STFC, 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy, RCUK, Astronomy and Astrophysics, Centaur, Astrometry, Albedo, Photometry (astronomy), Space and Planetary Science, Sky, astro-ph.EP, astrometry, Kuiper belt: general, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: Transneptunian objects (TNOs) are a source of invaluable information to access the history and evolution of the outer solar system. However, observing these faint objects is a difficult task. As a consequence, important properties such as size and albedo are known for only a small fraction of them. Now, with the results from deep sky surveys and the Gaia space mission, a new exciting era is within reach as accurate predictions of stellar occultations by numerous distant small solar system bodies become available. From them, diameters with kilometer accuracies can be determined. Albedos, in turn, can be obtained from diameters and absolute magnitudes. We use observations from the Dark Energy Survey (DES) from November 2012 until February 2016, amounting to 4292847 CCD frames. We searched them for all known small solar system bodies and recovered a total of 202 TNOs and Centaurs, 63 of which have been discovered by the DES collaboration until the date of this writing. Their positions were determined using the Gaia Data Release 2 as reference and their orbits were refined. Stellar occultations were then predicted using these refined orbits plus stellar positions from Gaia. These predictions are maintained, and updated, in a dedicated web service. The techniques developed here are also part of an ambitious preparation to use the data from the Large Synoptic Survey Telescope (LSST), that expects to obtain accurate positions and multifilter photometry for tens of thousands of TNOs., 25 pages, submitted to Astronomical Journal
Published: 2019

10. The first observed stellar occultations by the irregular satellite Phoebe (Saturn IX) and improved rotational period

Author: Marcelo Assafin, B E Morgado, Sohrab Rahvar, Julio Camargo, Colin Snodgrass, J. Campbell-White, Emmanuel Jehin, G. Benedetti-Rossi, Josselin Desmars, M. Owada, K Hosoi, Tsutomu Hayamizu, L A Mammana, T Hirose, A. R. Gomes-Júnior, E. Fernández-Lajús, R Horvat, D. Giles, Bruno Sicardy, S. Kerr, R. Vieira-Martins, Darren Maybour, Felipe Braga-Ribas, T. Barry, A De Horta, D. I. Machado, W. Hanna, Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), 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), Observatorio Nacional [Rio de Janeiro], 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), Western Sydney University, University of Dundee, Universidad Nacional de Mar del Plata [Mar del Plata] (UNMdP), Royal Astronomical Society of New Zealand [Waikanae], Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Astronomical Association of Queensland (AAQ), Unioeste - Universidade Estadual do Oeste do Paraná, School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), São Paulo State University (UNESP), Universidade Federal do Rio de Janeiro [Rio de Janeiro] (UFRJ), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Western Sydney University (UWS), The Open University [Milton Keynes] (OU), Universidade Estadual Paulista (Unesp), Laboratório Interinstitucional de E-Astronomia - LIneA, Federal University of Technology - Paraná (UTFPR / DAFIS), Observatório Nacional/MCTI, Section Meudon, Institut Poytechnique des Sciences Avancées IPSA, Univ. Lille, Engineering and Mathematics, Universidad Nacional de la Plata, CONICET/UNLP, International Occultation Timing Association (IOTA), Japan Occultation Information Network (JOIN), Astronomical Association of Queensland, Royal Astronomical Society of New Zealand (RASNZ), Polo Astroñomico Casimiro Montenegro Filho/FPTI-BR, Universidade Estadual Do Oeste Do Paraná, Complejo Astronómico El Leoncito (CASLEO), Sharif University of Technology, Royal Observatory, 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), and Universidade Estadual do Oeste do Paraná (UNIOESTE)
Subjects: Rotation period, Physics, Ciencias Astronómicas, 010504 meteorology & atmospheric sciences, Saturn (rocket family), Astronomy, Astronomy and Astrophysics, 01 natural sciences, Astronomía, satellites: individual: Phoebe, planets, Space and Planetary Science, Planet, individual: Phoebe [Planets and satellites], 0103 physical sciences, occultations, Satellite, Occultations, planets and satellites: individual: Phoebe, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We report six stellar occultations by (Saturn IX) Phoebe, an irregular satellite of Saturn, obtained between mid-2017 and mid-2019. The 2017 July 06 event is the first stellar occultation by an irregular satellite ever observed. The occultation chords were compared to a 3D shape model of the satellite obtained from Cassini observations. The rotation period available in the literature led to a sub-observer point at the moment of the observed occultations where the chords could not fit the 3D model. A procedure was developed to identify the correct sub-observer longitude. It allowed us to obtain the rotation period with improved precision over currently known value from literature. We show that the difference between the observed and the predicted sub-observer longitude suggests two possible solutions for the rotation period. By comparing these values with recently observed rotational light curves and single-chord stellar occultations, we can identify the best solution for Phoebe's rotational period as $9.27365 \pm 0.00002$ h. From the stellar occultations, we also obtained 6 geocentric astrometric positions in the ICRS as realised by the Gaia-DR2 with uncertainties at the 1-mas level., Instituto de Astrofísica de La Plata
Published: 2019

11. Non-relativistic energy density functionals

Author: Felipe Braga-Ribas, Julio Camargo, Marcelo Assafin, R. Vieira Martins, Bruno Sicardy, A. Andrei, D. N. da Silva Neto, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Nicolas Schunck
Subjects: Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2019

12. APPROX -mutual approximations between the Galilean moons: the 2016-2018 observational campaign

Author: R. Vieira-Martins, G. Borderes-Motta, B. C. B. Camargo, T. de Santana, J. O. Miranda, Marcelo Assafin, D. I. Machado, G. Benedetti-Rossi, T. Moura, A. Crispim, M. Malacarne, V. Robert, Othon C. Winter, T. Bassallo, T. A. R. Yamashita, Valéry Lainey, Rafael Sfair, S. Santos-Filho, A. Dias-Oliveira, L. A. G. Boldrin, B. E. Morgado, Felipe Braga-Ribas, Julio Camargo, F. K. Ribeiro, L. L. Trabuco, A. R. Gomes-Júnior, 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), Observatorio Nacional [Rio de Janeiro], Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Observatório Nacional/MCT, Institut Polytechnique des Sciences Avancées (IPSA), Centro Algoritmi, University of Minho, Guimarães, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Iwate University, University of Minho [Braga], Observatório Nacional/MCTIC, Laboratório Interinstitucional de e-Astronomia - LIneA, Universidade Estadual do Oeste do Paraná (Unioeste), Polo Astronômico Casimiro Montenegro Filho/FPTI-BR, Universidade Estadual Paulista (Unesp), Universidade Federal do Espírito Santo (UFES), Federal University of Technology - Paraná (UTFPR/DAFIS), Institut Polytechnique des Sciences Avancées IPSA, Univ. Lille 1, Escola SESC de Ensino Médio, and California Institute of Technology
Subjects: individual: europa [Planets and satellites], media_common.quotation_subject, individual: ganymede [Planets and satellites], Planets, FOS: Physical sciences, Ephemeris, 01 natural sciences, Jovian, law.invention, Telescope, Jupiter, symbols.namesake, law, 0103 physical sciences, 10. No inequality, data analysis [Methods], 010303 astronomy & astrophysics, media_common, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Astrometry, individual: callisto [Planets and satellites], Galilean moons, individual: io [Satellites], Space and Planetary Science, Sky, symbols, Natural satellite, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The technique of mutual approximations accurately gives the central instant at the maximum apparent approximation of two moving natural satellites in the sky plane. This can be used in ephemeris fitting to infer the relative positions between satellites with high precision. Only the mutual phenomena -- occultations and eclipses -- may achieve better results. However, mutual phenomena only occur every six years in the case of Jupiter. Mutual approximations do not have this restriction and can be observed at any time along the year as long as the satellites are visible. In this work, we present 104 central instants determined from the observations of 66 mutual approximations between the Galilean moons carried out at different sites in Brazil and France during the period 2016--2018. For 28 events we have at least two independent observations. All telescopes were equipped with a narrow-band filter centred at 889 nm with a width of 15 nm to eliminate the scattered light from Jupiter. The telescope apertures ranged between 25--120 cm. For comparison, the precision of the positions obtained with classical CCD astrometry is about 100 mas, for mutual phenomena it can achieve 10 mas or less and the average internal precision obtained with mutual approximations was 11.3 mas. This new kind of simple, yet accurate observations can significantly improve the orbits and ephemeris of Galilean satellites and thus be very useful for the planning of future space missions aiming at the Jovian system., Comment: 12 pages, 7 figures
Published: 2019

13. The trans-Neptunian object (84922) 2003 VS2 through stellar occultations

Author: A. Ceretta, Pablo Santos-Sanz, Thierry-Pascal Baum, M. Malacarne, F. L. Rommel, Gonzalo Tancredi, G. Rojas, A. Alvarez-Candal, Joe Pollock, A. Peyrot, Carine Jacques, J. L. Ortiz, S. Roland, Marcelo Assafin, F. Feys, Valentin D. Ivanov, Estela Fernández-Valenzuela, Alain Maury, Ricardo Gil-Hutton, Frédéric Vachier, Shai Kaspi, J. Desmars, D. Bérard, R. Melia, Emmanuel Jehin, Noah Brosch, Felipe Braga-Ribas, A. Pratt, L. Almenares, J. Spagnotto, P. Cacella, R. A. Artola, G. Benedetti-Rossi, Julio Camargo, Rene Duffard, A. R. Gomes-Júnior, Raoul Behrend, Nicolás Morales, A. F. Colas, Cyrielle Opitom, C. Colazo, S. Moindrot, R. Sfair, A. Milone, D. I. Machado, Ilan Manulis, R. Vieira-Martins, Marcelo Emilio, J. Lecacheux, Federica B. Bianco, B. E. Morgado, J.-P. Teng, Bruno Sicardy, Observatório Nacional (ON/MCTIC), INCT do e-Universo, Section Meudon, IAA-CSIC, Universidade Federal do Rio de Janeiro (UFRJ), Univ. Paris Diderot, CNRS UMR F-8028, Federal University of Technology—Paraná (UTFPR/DAFIS), University of Central Florida, Facultad de Ciencias, Estación Astrofísica de Bosque Alegre, Observatoire Astronomique des Makes, Observatoire de Genève, University of Delaware, Joseph R. Biden Jr. School for Public Policy and Administration, Data Science Institute, Center for Urban Science and Progress, Tel Aviv University, Observatorio Astronómico Los Molinos, Universidade Estadual Paulista (Unesp), ESO, University of Liège, San Pedro de Atacama Celestial Explorations, European Southern Observatory—Alonso de Cordova 3107, Appalachian State University, European Section, Universidad de la Republica, Observatorio El Catalejo, DogsHeaven Observatory X87, Universidade Estadual de Ponta Grossa (UEPG), San Juan National University and CONICET, Southern Observatory for Near Earth Asteroids Research (SONEAR), Universidade Estadual do Oeste do Paraná (Unioeste), FPTI-BR, Universidade Federal do Espírito Santo (UFES), Weizmann Institute of Science, National Institute for Space Research (INPE), Universidade Federal de São Carlos (UFSCar), 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), 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), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil), European Research Council, European Commission, Ministerio de Economía y Competitividad (España), Junta de Andalucía, Ministerio de Ciencia, Innovación y Universidades (España), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, and Fonds de la Recherche Scientifique (Fédération Wallonie-Bruxelles)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, European community, Kuiper belt (893), We present results from three world-wide campaigns that resulted in the detections of two single-chord and one multi-chord stellar occultations by the plutino object (84922) 2003 VS2. From the single-chord occultations in 2013 and 2014 we obtained accurate astrometric positions for the object, while from the multi-chord occultation on 2014 November 7, we obtained the parameters of the best-fitting ellipse to the limb of the body at the time of occultation. We also obtained short-term photometry data for the body in order to derive its rotational phase during the occultation. The rotational light curve present a peak-to-peak amplitude of 0.141 ± 0.009 mag. This allows us to reconstruct the 3D shape of the body, with principal semi-axes of a = 313.8 ± 7.1 km, b = 265.5- + 9.8 8.8 km, and c = 247.3- + 43.6 26.6 km, which is not consistent with a Jacobi triaxial equilibrium figure. The derived spherical volume equivalent diameter of 548.3- + 44.6 29.5 km is about 5% larger than the radiometric diameter of 2003 VS2 derived from Herschel data of 523 ± 35 km, but still compatible with it within error bars. From those results we can also derive the geometric albedo (0.123- + 0.014 0.015) and, under the assumption that the object is a Maclaurin spheroid, the density r = 1400- + 300 1000 for the plutino. The disappearances and reappearances of the star during the occultations do not show any compelling evidence for a global atmosphere considering a pressure upper limit of about 1 microbar for a pure nitrogen atmosphere, nor secondary features (e.g., rings or satellite) around the main body. © 2019. The American Astronomical Society. All rights reserved, European research, FOS: Physical sciences, Library science, Astronomy and Astrophysics, 01 natural sciences, Unified Astronomy Thesaurus concepts), State agency, Trans-Neptunian objects (1705), Space and Planetary Science, 0103 physical sciences, media_common.cataloged_instance, European union, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, media_common
Abstract: We present results from three world-wide campaigns that resulted in the detections of two single-chord and one multi-chord stellar occultations by the plutino object (84922) 2003 VS2. From the single-chord occultations in 2013 and 2014 we obtained accurate astrometric positions for the object, while from the multi-chord occultation on 2014 November 7, we obtained the parameters of the best-fitting ellipse to the limb of the body at the time of occultation. We also obtained short-term photometry data for the body in order to derive its rotational phase during the occultation. The rotational light curve present a peak-to-peak amplitude of 0.141 ± 0.009 mag. This allows us to reconstruct the 3D shape of the body, with principal semi-axes of a = 313.8 ± 7.1 km, b = 265.5- + 9.8 8.8 km, and c = 247.3- + 43.6 26.6 km, which is not consistent with a Jacobi triaxial equilibrium figure. The derived spherical volume equivalent diameter of 548.3- + 44.6 29.5 km is about 5% larger than the radiometric diameter of 2003 VS2 derived from Herschel data of 523 ± 35 km, but still compatible with it within error bars. From those results we can also derive the geometric albedo (0.123- + 0.014 0.015) and, under the assumption that the object is a Maclaurin spheroid, the density r = 1400- + 300 1000 for the plutino. The disappearances and reappearances of the star during the occultations do not show any compelling evidence for a global atmosphere considering a pressure upper limit of about 1 microbar for a pure nitrogen atmosphere, nor secondary features (e.g., rings or satellite) around the main body. © 2019. The American Astronomical Society. All rights reserved., G.B.-R. is thankful for the support of the CAPES and FAPERJ/PAPDRJ (E26/203.173/2016) grant. Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ERC grant agreement No. 669416 >LUCKY STAR>). 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 (SBNAF). P.S.-S. and J.L.O. 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. P.S.-S., J.L.O., and R.D. 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 Astrofisica de Andalucia (SEV-2017-0709). Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program ID 094.C-0352. M. A. thanks CNPq (grants 427700/2018-3, 310683/2017-3, and 473002/2013-2) and FAPERJ (grant E-26/111.488/2013). J.I.B.C. acknowledges CNPq grant 308150/2016-3. R. V.-M. thanks grants: CNPq-304544/2017-5, 401903/2016-8, Faperj: PAPDRJ-45/2013, and E-26/203.026/2015. F.B.-R. acknowledges CNPq grant 309578/2017-5. E.F.-V. acknowledges UFC 2017 Preeminent Postdoctoral Program (P3). 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. E.J. is a FNRS Senior Research Associate. A.A.C. acknowledges support from FAPERJ (grant E-26/203.186/2016) and CNPq grants (304971/2016-2 and 401669/2016-5). B.M. thanks the CAPES/Cofecub-394/2016-05 grant. A.R.G.J. and R.S. thank the financial support of FAPESP (proc. 2018/11239-8, proc. 2011/08171-3, proc. 2016/24561-0). A. M. thanks Caisey Harlingten for the use of his 50 cm telescope. We thank V. Buso and R. Condori for the observation efforts.
Published: 2019

14. GravityCam : wide-field high-resolution high-cadence imaging surveys in the visible from the ground

Author: M. Hundertmark, Colin Snodgrass, Sergio Ortolani, Craig D. Mackay, Benoit Carry, Valentin D. Ivanov, A. Doressoundiram, Martin Dominik, U. G. Jørgensen, Daniel F. Evans, Iain A. Steele, Stephen Serjeant, Jesper Skottfelt, Konstantin D. Stefanov, Felipe Braga-Ribas, Poshak Gandhi, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and 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)
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO), astronomical technology, detectors, seeing, Dark matter, Population, T-NDAS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, law.invention, micro [Gravitational lensing], Telescope, law, 0103 physical sciences, QB Astronomy, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Adaptive optics, education, 010303 astronomy & astrophysics, Image resolution, Instrumentation and Methods for Astrophysics (astro-ph.IM), Galaxy cluster, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QC, astronomical technology, detectors, ) planetary systems [(stars], QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, general [Kuiper belt], seeing, Galaxy, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], weak [Gravitational lensing], Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: GravityCam is a new concept of ground-based imaging instrument capable of delivering significantly sharper images from the ground than is normally possible without adaptive optics. Advances in optical and near infrared imaging technologies allow images to be acquired at high speed without significant noise penalty. Aligning these images before they are combined can yield a 2.5 to 3 fold improvement in image resolution. By using arrays of such detectors, survey fields may be as wide as the telescope optics allows. Consequently, GravityCam enables both wide-field high-resolution imaging and high-speed photometry. We describe the instrument and detail its application to provide demographics of planets and satellites down to Lunar mass (or even below) across the Milky Way. GravityCam is also suited to improve the quality of weak shear studies of dark matter distribution in distant clusters of galaxies and multiwavelength follow-ups of background sources that are strongly lensed by galaxy clusters. The photometric data arising from an extensive microlensing survey will also be useful for asteroseismology studies, while GravityCam can be used to monitor fast multiwavelength flaring in accreting compact objects, and promises to generate a unique data set on the population of the Kuiper belt and possibly the Oort cloud., Comment: 23 pages, 15 figures. Revision submitted to Proceedings of the Astronomical Society of Australia, 25 September 2018
Published: 2018

15. The future of stellar occultations by distant solar system bodies: Perspectives from the Gaia astrometry and the deep sky surveys

Author: Felipe Braga-Ribas, Julio Camargo, Marcelo Assafin, D. Bérard, G. Benedetti-Rossi, Roberto Vieira-Martins, Bruno Sicardy, Josselin Desmars, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatorio Nacional [Rio de Janeiro], and 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)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, FOS: Physical sciences, Large Synoptic Survey Telescope, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Key point, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Astrometry, Space and Planetary Science, Sky, Stellar occultation, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: Distant objects in the solar system are crucial to better understand the history and evolution of its outskirts. The stellar occultation technique allows the determination of their sizes and shapes with kilometric accuracy, a detailed investigation of their immediate vicinities, as well as the detection of tenuous atmospheres. The prediction of such events is a key point in this study, and yet accurate enough predictions are available to a handful of objects only. In this work, we briefly discuss the dramatic impact that both the astrometry from the Gaia space mission and the deep sky surveys -- the Large Synoptic Survey Telescope in particular -- will have on the prediction of stellar occultations and how they may influence the future of the study of distant small solar system bodies through this technique., 10 pages, 3 figures, ACM2017
Published: 2018

16. 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

17. Results from a triple chord stellar occultation and far-infrared photometry of the trans-Neptunian object (229762) 2007 UK126

Author: Jerry Bardecker, Julio Camargo, Thomas Müller, Alfred Krabbe, Jürgen Wolf, Aart M. Olsen, Dave Herald, Felipe Braga-Ribas, Jose Luis Ortiz, Karsten Schindler, Csaba Kiss, European Commission, Hungarian Scientific Research Fund, Junta de Andalucía, German Academic Exchange Service, Universities Space Research Association (US), European Space Agency, and National Research, Development and Innovation Office (Hungary)
Subjects: Rotation period, 010504 meteorology & atmospheric sciences, Kuiper belt objects: individual: (229762) 2007 UK126, FOS: Physical sciences, Astrophysics, individual: (229762) 2007 UK126 [Kuiper belt objects], Ellipse, 01 natural sciences, Occultation, Photometry (optics), Far infrared, Planet, Geometric albedo, Methods: data analysis, 0103 physical sciences, Trans-Neptunian object, data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Astronomy and Astrophysics, Radiation mechanisms: thermal, 13. Climate action, Space and Planetary Science, thermal [Radiation mechanisms], Occultations, Astrophysics - Earth and Planetary Astrophysics
Abstract: Schindler, K. et. al., Context. A stellar occultation by a trans-Neptunian object (TNO) provides an opportunity to probe the size and shape of these distant solar system bodies. In the past seven years, several occultations by TNOs have been observed, but mostly from a single location. Only very few TNOs have been sampled simultaneously from multiple locations. Sufficient data that enable a robust estimation of shadow size through an ellipse fit could only be obtained for two objects. Aims. We present the first observation of an occultation by the TNO 2007 UK126 on 15 November 2014, measured by three observers, one nearly on and two almost symmetrical to the shadow's centerline. This is the first multi-chord dataset obtained for a so-called detached object, a TNO subgroup with perihelion distances so large that the giant planets have likely not perturbed their orbits. We also revisit Herschel/PACS far-infrared data, applying a new reduction method to improve the accuracy of the measured fluxes. Combining both datasets allows us to comprehensively characterize 2007 UK126. Methods. We use error-in-variable regression to solve the non-linear problem of propagating timing errors into uncertainties of the ellipse parameters. Based on the shadow's size and a previously reported rotation period, we expect a shape of a Maclaurin spheroid and derive a geometrically plausible size range. To refine our size estimate of 2007 UK126, we model its thermal emission using a thermophysical model code. We conduct a parametric study to predict far-infrared fluxes and compare them to the Herschel/PACS measurements. Results. The favorable geometry of our occultation chords, combined with minimal dead-time imaging, and precise GPS time measurements, allow for an accurate estimation of the shadow size (best-fitting ellipse with axes 645.80 +/- 5.68 km x 597.81 +/- 12.74 km) and the visual geometric albedo (p(V) = 15.0 +/- 1.6%). By combining our analyses of the occultation and the far-infrared data, we can constrain the effective diameter of 2007 UK126 to d(eff) = 599-629 km. We conclude that subsolar surface temperatures are in the order of approximate to 50 55 K., K.S. has been supported financially by a one-year fellowship from the German Academic Exchange Service (DAAD) during his stay at NASA Ames Research Center, CA as part of his Ph.D. research. K.S. would also like to thank the Universities Space Research Association (USRA) for their support throughout his thesis. T.M., C.K. and J.L.O. have received funding from the European Union's Horizon 2020 Research and Innovation Programme, under Grant Agreement No. 687378. C.K. has been supported by the PECS grant # 4000109997/13/NL/KML of the Hungarian Space Office and the European Space Agency, the K-104607 grant of the Hungarian Research Fund (OTKA), and the GINOP-2.3.2-15-2016 00003 grant of the National Research, Development and Innovation Office of Hungary (NKFIH). J.L.O. acknowledges support from Proyecto de Excelencia J.A. 2012-FQM1776.
Published: 2017

18. RESULTS FROM THE 2014 NOVEMBER 15TH MULTI-CHORD STELLAR OCCULTATION BY THE TNO (229762) 2007 UK 126

Author: Nicolás Morales, Marcelo Assafin, Josselin Desmars, Stephen E. Levine, R. Vieira-Martins, Rodrigo Leiva, Pablo Santos-Sanz, Felipe Braga-Ribas, Jonathan Irwin, G. Benedetti-Rossi, M. A. Gómez-Muñoz, A. R. Gomes-Júnior, Aart M. Olsen, Jerry Bardecker, James K. Bean, Marc W. Buie, David Charbonneau, Bruno Sicardy, Rene Duffard, J. L. Ortiz, R. Sumner, Leonel Gutierrez, Larry Wasserman, Julio Camargo, A. Dias-Oliveira, Audrey Thirouin, John Keller, D. W. Ruby, Brian A. Skiff, Observatorio Nacional [Rio de Janeiro], Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Paul Scherrer Institute (PSI), Observatório Nacional/MCT, Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Southwest Research Institute [Boulder] (SwRI), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), 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), Universidade Federal do Rio de Janeiro [Rio de Janeiro] (UFRJ), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Junta de Andalucía, Ministerio de Economía y Competitividad (España), European Commission, National Science Foundation (US), European Research Council, Fundação de Amparo à Pesquisa e Inovação do Espírito Santo, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), and Consejo Nacional de Ciencia y Tecnología (México)
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Chord (geometry), 010504 meteorology & atmospheric sciences, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, individual (229762, 2007 UK126) [Kuiper belt objects], 01 natural sciences, fundamental parameters [planets and satellites], Space and Planetary Science, occultations, 0103 physical sciences, Stellar occultation, Kuiper belt objects: individual (229762, 2007 UK126), planets and satellites: fundamental parameters, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: Benedetti-Rossi, G. et. al., We present results derived from the first multi-chord stellar occultation by the trans-Neptunian object (229762) 2007 UK, observed on 2014 November 15. The event was observed by the Research and Education Collaborative Occultation Network project and International Occultation Timing Association collaborators throughout the United States. Use of two different data analysis methods obtain a satisfactory fit to seven chords, yielding an elliptical fit to the chords with an equatorial radius of R = 338 km and equivalent radius of R = 319 km. A circular fit also gives a radius of R = 324 km. Assuming that the object is a Maclaurin spheroid with indeterminate aspect angle, and using two published absolute magnitudes for the body, we derive possible ranges for geometric albedo between p = 0.159 and p = 0.189 , and for the body oblateness between ∈ = 0.105 and ∈ = 0.118 . For a nominal rotational period of 11.05 hr, an upper limit for density of ρ = 1740 kg m is estimated for the body., The RECON project would not be possible without all of the support from our community teams (teachers, students, and community members) and was funded by NSF grants AST-1212159, AST-1413287, and AST-1413072. Special thanks to Dean and Starizona for their support of RECON above and beyond the usual bounds of a commercial relationship. Part of the research 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>). Funding from Spanish grant AYA-2014-56637-C2-1-P is acknowledged, as is the Proyecto de Excelencia de la Junta de Andaluca, J. A. 2012-FQM1776. R.D. acknowledges the support of MINECO for his Ramon y Cajal Contract. FEDER funds are also acknowledged. A.D.O. is thankful for the support of the CAPES (BEX 9110/12-7) FAPERJ/PAPDRJ (E-26/200.464/2015) grants. G.B.R. is thankful for the support of CAPES/Brazil and FAPERJ (Grant E-01/2015/209545). J.I.B.C. acknowledges CNPq for a PQ2 fellowship (process number 308489/2013-6). L.G. thanks the support from CONACYT through grant 167236. M.A. thanks the CNPq (Grants 473002/2013-2 and 308721/2011-0) and FAPERJ (Grant E-26/111.488/2013). P.S.-S. acknowledges that part of the research leading to these results has received funding from the European Unions Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378. R.V.M. acknowledges the following grants: CNPq-306885/2013, CAPES/Cofecub-2506/2015, FAPERJ/PAPDRJ-45/2013, FAPERJ/CNE/05-2015.
Published: 2016

19. Pluto's Atmosphere from the 2015 June 29 Ground-Based Stellar Occultation at the Time of the New Horizons Flyby

Author: Marcelo Assafin, J. Bradshaw, J. Milner, Jean Lecacheux, B. Loader, D. Giles, G. Benedetti-Rossi, P. A. Yock, S. Todd, P. B. Graham, P. Nosworthy, Ronan Cunniffe, D. Jenke, Dan M. Watson, M. Forbes, Felipe Braga-Ribas, D. Dunham, G. L. White, R. Horvat, P. F. Skilton, Jack D. Drummond, P. Purcell, A. Dias-Oliveira, M. Harnisch, J. L. Ortiz, Pierre Kervella, K. M. Hill, A. Pennell, R. Glassey, R. Groom, J. Broughton, J. Newman, W. Beisker, W. H. Allen, Hadrien A. R. Devillepoix, Rene Duffard, J. P. Beaulieu, M. Streamer, E. Meza, S. Kerr, R. Jansen, Bruno Sicardy, Andrew A. Cole, Diane Berard, L. Davis, A. J. Castro-Tirado, G. McKay, R. Idaczyk, D. Hooper, M. A. Barry, Martin Jelínek, A. B. Giles, Roberto Vieira-Martins, Julio Camargo, L. Field, G. Hudson, S. Parker, D. Gault, Richard Querel, H. Watanabe, M. Unwin, Josselin Desmars, A. Ramos-Gomes-Jr., B. Lade, H. Pavlov, E. Lellouch, D. Herald, John Talbot, 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), Occultation Section [Wellington], Royal Astronomical Society of New Zealand, Observatorio Nacional [Rio de Janeiro], 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), Shanghai Astronomical Observatory [Shanghai] (SHAO), Chinese Academy of Sciences [Beijing] (CAS), Heriot-Watt University [Edinburgh] (HWU), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), International Occultation Timing Association European Section (IOTA ES), International Occultation Timing Association European Section, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Instituto de Astrofsica de Andalucia, National Institute of Water and Atmospheric Research [Wellington] (NIWA), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Groningen Bioinformatics Centre, GBB, University of Groningen [Groningen], Ageing Group, Centre for Public Health, Queen's University [Belfast] (QUB), Health Center Research Institute, McGill University = Université McGill [Montréal, Canada], Reedy Creek, Center for Science Communication, University of Otago [Dunedin, Nouvelle-Zélande], Laboratoire d'Ingénierie des Matériaux de Bretagne (LIMATB), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO), Astronomical Society of Western Australia (ASWA), Stockport Observatory, Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Kuriwa Observatory, Canberra Astronomical Society, Department of Electrical and Computer Engineering [Alberta], University of Alberta, Observatório Nacional/MCT, Universidade Federal do Rio de Janeiro [Rio de Janeiro] (UFRJ), International Occultation Timing Association (IOTA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), National Institute of Water and Atmospheric Research [Lauder] (NIWA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Royal Observatory (UKATC), Stanford University [Stanford], Department of Physics and Atmospheric Science [Halifax], Dalhousie University [Halifax], STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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), Stanford University, 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 ), Shanghai Astronomical Observatory [Shanghai] ( SHAO ), Chinese Academy of Sciences [Beijing] ( CAS ), Heriot-Watt University [Edinburgh] ( HWU ), 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 ), Universidade Federal do Rio de Janeiro [Rio de Janeiro] ( UFRJ ), International Occultation Timing Association European Section ( IOTA ES ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), National Institute of Water and Atmospheric Research (NIWA), Lauder, New Zealand, Institut d'Astrophysique de Paris ( IAP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), The Queen's University of Belfast, McGill University, University of Otago, Laboratoire d'Ingénierie des Matériaux de Bretagne ( LIMATB ), Université de Bretagne Sud ( UBS ) -Université de Brest ( UBO ) -Institut Brestois du Numérique et des Mathématiques ( IBNM ), Université de Brest ( UBO ) -Université de Brest ( UBO ), Astronomical Society of Western Australia, and Niels Bohr Institute ( NBI )
Subjects: [PHYS]Physics [physics], New horizons, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy, Astronomy and Astrophysics, Surface pressure, Block (meteorology), 01 natural sciences, Atmosphere, Pluto, Temperature gradient, Flash (photography), Amplitude, 13. Climate action, Space and Planetary Science, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Geology, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience; We present results from a multi-chord Pluto stellar occultation observed on 2015 June 29 from New Zealand and Australia. This occurred only two weeks before the NASA New Horizons flyby of the Pluto system and serves as a useful comparison between ground-based and space results. We find that Pluto's atmosphere is still expanding, with a significant pressure increase of 5 ± 2% since 2013 and a factor of almost three since 1988. This trend rules out, as of today, an atmospheric collapse associated with Pluto's recession from the Sun. A central flash, a rare occurrence, was observed from several sites in New Zealand. The flash shape and amplitude are compatible with a spherical and transparent atmospheric layer of roughly 3 km in thickness whose base lies at about 4 km above Pluto's surface, and where an average thermal gradient of about 5 K km−1 prevails. We discuss the possibility that small departures between the observed and modeled flash are caused by local topographic features (mountains) along Pluto's limb that block the stellar light. Finally, using two possible temperature profiles, and extrapolating our pressure profile from our deepest accessible level down to the surface, we obtain a possible range of 11.9–13.7 μbar for the surface pressure.
Published: 2016

20. James Webb Space Telescope Observations of Stellar Occultations by Solar System Bodies and Rings

Author: Felipe Braga-Ribas, Stefanie N. Milam, Noemi Pinilla-Alonso, Zhong-Yi Lin, Leslie A. Young, Th. Müller, Esa Vilenius, Pablo Santos-Sanz, J. L. Ortiz, Gonzalo Tancredi, John Stansberry, Amanda S. Bosh, Z. W. Zhang, Rene Duffard, Emmanuel Lellouch, Richard G. French, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Max-Planck-Institut für Extraterrestrische Physik (MPE), Observatório Nacional/MCT, 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, and 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)
Subjects: Physics, [PHYS]Physics [physics], Solar System, 010504 meteorology & atmospheric sciences, James Webb Space Telescope, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Lagrangian point, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Occultation, Space and Planetary Science, 0103 physical sciences, Orbit (dynamics), Astrophysics::Solar and Stellar Astrophysics, Stellar occultation, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: In this paper, we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of Solar System bodies and rings using stellar occultations. The strengths and weaknesses of the stellar occultation technique are evaluated in light of JWST's unique capabilities. We identify several possible JWST occultation events by minor bodies and rings and evaluate their potential scientific value. These predictions depend critically on accurate a priori knowledge of the orbit of JWST near the Sun–Earth Lagrange point 2 (L2). We also explore the possibility of serendipitous stellar occultations by very small minor bodies as a byproduct of other JWST observing programs. Finally, to optimize the potential scientific return of stellar occultation observations, we identify several characteristics of JWST's orbit and instrumentation that should be taken into account during JWST's development.
Published: 2016

21. Astrometry of the main satellites of Uranus: 18 years of observations

Author: Felipe Braga-Ribas, R. Vieira-Martins, Marcelo Assafin, D. N. da Silva Neto, G. Benedetti-Rossi, Julio Camargo, A. Dias-Oliveira, F. P. Magalhaes, A. R. Gomes-Júnior, Alexandre Humberto Andrei, Observatorio Nacional [Rio de Janeiro], 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), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Observatório Nacional/MCT, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Solar System, Uranus, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrometry, Ephemeris, Declination, Oberon, Space and Planetary Science, Observatory, Right ascension, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], computer, ComputingMilieux_MISCELLANEOUS, computer.programming_language, Astrophysics - Earth and Planetary Astrophysics
Abstract: We determine accurate positions of the main satellites of Uranus: Miranda, Ariel, Umbriel, Titania, and Oberon. Positions of Uranus, as derived from those of these satellites, are also determined. The observational period spans from 1992 to 2011. All runs were made at the Pico dos Dias Observatory, Brazil. We used the software called Platform for Reduction of Astronomical Images Automatically (PRAIA) to minimise (digital coronography) the influence of the scattered light of Uranus on the astrometric measurements and to determine accurate positions of the main satellites. The positions of Uranus were then indirectly determined by computing the mean differences between the observed and ephemeris positions of these satellites. A series of numerical filters was applied to filter out spurious data. These filters are mostly based on the comparison between the positions of Oberon with those of the other satellites and on the offsets as given by the differences between the observed and ephemeris positions of all satellites. We have, for the overall offsets of the five satellites, -29 (+/-63) mas in right ascension and -27 (+/-46) mas in declination. For the overall difference between the offsets of Oberon and those of the other satellites, we have +3 (+/-30) mas in right ascension and -2 (+/-28) mas in declination. Ephemeris positions for the satellites were determined from DE432+ura111. Comparisons using other modern ephemerides for the solar system -INPOP13c- and for the motion of the satellites -NOE-7-2013- were also made. They confirm that the largest contribution to the offsets we find comes from the motion of the barycenter of the Uranus system around the barycenter of the solar system, as given by the planetary ephemerides. Catalogues with the observed positions are provided., Comment: 13 pages, 21 figures
Published: 2015

22. Results of two multichord stellar occultations by dwarf planet (1) Ceres

Author: J. B. Dunham, Breno L. Giacchini, C. Jacques, Bruno Sicardy, G. Benedetti-Rossi, P. D. Maley, F. R. Herpich, T. Blank, T. George, William Schoenell, J. Brooks, R. F. Dantowitz, Alexandre J. T. S. Mello, Marcelo Assafin, E. Pimentel, A. Milone, A. R. Gomes-Júnior, N. S. Weber, L. Mehret, Marcelo Emilio, Brad Timerson, J. Broughton, David W. Dunham, Chad K. Ellington, Felipe Braga-Ribas, Julio Camargo, R. Vieira-Martins, Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Observatório Nacional/MCT, Observatorio Nacional [Rio de Janeiro], Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), International Occultation Timing Association (IOTA), Reedy Creek, Universidade Estadual de Ponta Grossa, Universidade Estadual de Ponta Grossa - State University of Ponta Grossa (UEPG), Instituto Nacional de Pesquisas Espaciais (INPE), Ministério da Ciência, Tecnologia e Inovação, and Universität Paderborn (UPB)
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Dwarf planet, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Occultation, Space and Planetary Science, Asteroid, Aspect angle, Polar, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the results of two multi-chord stellar occultations by the dwarf planet (1) Ceres that were observed from Brazil on 2010 August 17, and from the USA on 2013 October 25. Four positive detections were obtained for the 2010 occultation, and nine for the 2013 occultation. Elliptical models were adjusted to the observed chords to obtain Ceres' size and shape. Two limb fitting solutions were studied for each event. The first one is a nominal solution with an indeterminate polar aspect angle. The second one was constrained by the pole coordinates as given by Drummond et al. Assuming a Maclaurin spheroid, we determine an equatorial diameter of 972 $\pm$ 6 km and an apparent oblateness of 0.08 $\pm$ 0.03 as our best solution. These results are compared to all available size and shape determinations for Ceres made so far, and shall be confirmed by the NASA's Dawn space mission., 9 pages, 6 figures. Accepted for publication in MNRAS
Published: 2015

23. Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations

Author: Valery Lainey, Marcelo Assafin, R. Vieira-Martins, B. E. Morgado, G. Benedetti-Rossi, A. Dias-Oliveira, William Thuillot, Felipe Braga-Ribas, D. N. da Silva Neto, A. R. Gomes-Júnior, Jean-Eudes Arlot, Alexandre Humberto Andrei, Julio Camargo, Josselin Desmars, Y. Duchemin, Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Observatorio Nacional [Rio de Janeiro], Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'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), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Pôle Instrumentation, Informatique et Systèmes, Institut de Recherche en Systèmes Electroniques Embarqués (IRSEEM), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-École Supérieure d’Ingénieurs en Génie Électrique (ESIGELEC)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-École Supérieure d’Ingénieurs en Génie Électrique (ESIGELEC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), 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), Universidade Federal do Rio de Janeiro [Rio de Janeiro] (UFRJ), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Technologie de Belfort-Montbeliard (UTBM), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Universidade Federal do Parana [Curitiba] (UFPR), Universidade Federal do Paraná (UFPR), and Centro Universitário Estadual da Zona Oeste [Rio de Janeiro] (UEZO)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Ephemeris, 01 natural sciences, Jupiter, Planet, Neptune, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], International Celestial Reference System, Uranus, Astronomy, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Astronomy and Astrophysics, Astrometry, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Space and Planetary Science, [INFO.INFO-ES]Computer Science [cs]/Embedded Systems, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: The irregular satellites of the giant planets are believed to have been captured during the evolution of the solar system. Knowing their physical parameters, such as size, density, and albedo is important for constraining where they came from and how they were captured. The best way to obtain these parameters are observations in situ by spacecrafts or from stellar occultations by the objects. Both techniques demand that the orbits are well known. We aimed to obtain good astrometric positions of irregular satellites to improve their orbits and ephemeris. We identified and reduced observations of several irregular satellites from three databases containing more than 8000 images obtained between 1992 and 2014 at three sites (Observat\'orio do Pico dos Dias, Observatoire de Haute-Provence, and European Southern Observatory - La Silla). We used the software PRAIA (Platform for Reduction of Astronomical Images Automatically) to make the astrometric reduction of the CCD frames. The UCAC4 catalog represented the International Celestial Reference System in the reductions. Identification of the satellites in the frames was done through their ephemerides as determined from the SPICE/NAIF kernels. Some procedures were followed to overcome missing or incomplete information (coordinates, date), mostly for the older images. We managed to obtain more than 6000 positions for 18 irregular satellites: 12 of Jupiter, 4 of Saturn, 1 of Uranus (Sycorax), and 1 of Neptune (Nereid). For some satellites the number of obtained positions is more than 50\% of what was used in earlier orbital numerical integrations. Comparison of our positions with recent JPL ephemeris suggests there are systematic errors in the orbits for some of the irregular satellites. The most evident case was an error in the inclination of Carme., Comment: 9 pages, with 3 being online material
Published: 2015

24. Evidence that Pluto’s atmosphere does not collapse from occultations including the 2013 May 04 event

Author: Emmanuel Jehin, Marcelo Assafin, A. Ramos Gomes, Leslie A. Young, Marc W. Buie, J. L. Ortiz, Alain Maury, M. Norbury, Catherine B. Olkin, R. C. Smith, Lawrence H. Wasserman, Richard G. French, Cyrielle Opitom, D. Borncamp, A. Dias de Oliveira, Nicolás Morales, Norbert Zacharias, Felipe Braga-Ribas, Federica B. Bianco, Bruno Sicardy, A. Pickles, Michaël Gillon, Eliot F. Young, M. Zacharias, Observatoire de Paris, Université Paris sciences et lettres (PSL), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Southern Observatory (ESO), Observatório Nacional/MCT, Southwest Research Institute [San Antonio] (SwRI), and National Aeronautics and Space Administration (US)
Subjects: Epoch (astronomy), Occultation, Astrobiology, Atmosphere, Astrophysics::Solar and Stellar Astrophysics, surface, Ice caps, Physics::Atmospheric and Oceanic Physics, ComputingMilieux_MISCELLANEOUS, Atmospheres, evolution, Physics, [PHYS]Physics [physics], Atmospheric pressure, Pluto, Pluto, atmosphere, Astronomy, Astronomy and Astrophysics, Pluto, surface, Atmospheres: evolution, evolution [Atmospheres], 13. Climate action, Space and Planetary Science, Physics::Space Physics, Orbit (dynamics), Astrophysics::Earth and Planetary Astrophysics, Occultations, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Event (particle physics)
Abstract: © 2014 The Authors. Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013, and models of energy balance between Pluto's surface and atmosphere, we find the preferred models are consistent with Pluto retaining a collisional atmosphere throughout its 248-year orbit. The occultation results show an increasing atmospheric pressure with time in the current epoch, a trend present only in models with a high thermal inertia and a permanent N2 ice cap at Pluto's north rotational pole., This work was supported in part by NASA Planetary Astronomy Grant NNX12AG25G.
Published: 2015

25. Photometric and spectroscopic evidence for a dense ring system around Centaur Chariklo

Author: Pablo Santos-Sanz, Rene Duffard, C. Colazo, Bruno Sicardy, Estela Fernández-Valenzuela, Felipe Braga-Ribas, Alvaro Alvarez-Candal, Jose Luis Ortiz, Nicolás Morales, Noemi Pinilla-Alonso, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Observatorio Astronómico de Córdoba (OAC), Universidad Nacional de Córdoba [Argentina], and Observatório Nacional/MCT
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Absolute magnitude, [PHYS]Physics [physics], FOS: Physical sciences, Astronomy and Astrophysics, Tholin, Astrophysics, Centaur, Spectral line, Light scattering, Photometry (optics), Amorphous carbon, 13. Climate action, Space and Planetary Science, Aspect angle, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics
Abstract: In this work we aim to study if the variability in the absolute magnitude of Chariklo and the temporal variation of the spectral ice feature, even its disappearance in 2007, can be explained by an icy ring system whose aspect angle changes with time. We modeled the light reflected by a system as the one described above to explain the variations on the absolute magnitude of Chariklo and its rings. Using X-Shooter at VLT we obtained a new reflectance spectra, here we compared this new set of data with the ones available in the literature. We showed how the water ice feature is visible in 2013 in accordance with the ring configuration, which had an opening angle of nearly 34$^o$ in 2013. Finally we also used models of the scattering of light to fit the visible and near-infrared spectra showing different characteristic to obtain information on the composition of Chariklo and its rings. {We showed that past absolute photometry of Chariklo from the literature and new photometric data that we obtained in 2013 can be explained by a ring of particles whose opening angle changes as a function of time. We used the two possible pole solutions for the ring system and found that only one of them, $\alpha$=151.30$\pm0.5$, $\delta=41.48\pm0.2$ $^o$ ($\lambda=137.9\pm0.5$, $\beta=27.7\pm0.2$ $^o$) provides the right variation of the aspect angle with time to explain the photometry, whereas the other possible pole solution fails to explain the photometry. From spectral modeling, using the result on the pole solution, we derived the composition of Chariklo surface and of that of the rings. Chariklo surface is composed by nearly 60% of amorphous carbon, 30% of silicates and 10\% of organics, no water ice was found on the surface. Whereas the ring contains 20% of water ice, 40-70% of silicates and 10-30% of tholins and small quantities of amorphous carbon., Comment: Astronomy and Astrophysics in press
Published: 2014

26. A ring system detected around the Centaur (10199) Chariklo

Author: K. M. Ivarsen, Kasper Harpsøe, Fernando Roig, N. Ligier, N. R. Frank, Rafael Sfair, Shenghong Gu, Jose Luis Ortiz, J. Lecacheux, Cyrielle Opitom, Jesper Skottfelt, J. B. Haislip, Joe Pollock, Nicolás Morales, L. Vanzi, Rodrigo Leiva, P. Lemos, François Colas, Gonzalo Tancredi, E. M. Schneiter, Frédéric Vachier, Xuefeng Wang, Marcelo Assafin, R. Vieira-Martins, R. G. Sandness, Colin Snodgrass, Nicolás Marín Martínez, Emmanuel Jehin, Marcelo Emilio, Jean Manfroid, L. Almenares, J. Spagnotto, Daniel E. Reichart, S. Roland, Martin Dominik, Thomas Widemann, U. G. Jørgensen, J. P. Moore, V. Perez, A. Ramos Gomes, C. Colazo, Markus Rabus, Pierre Kervella, D. I. Machado, Ricardo Gil-Hutton, L. Mehret, F. Roques, Julio Camargo, Bruno Sicardy, E. Lellouch, D. G. Lambas, G. Benedetti-Rossi, Alain Maury, L. Maquet, M. El Moutamid, A. Ceretta, Rene Duffard, R. Melia, Hektor Monteiro, Aaron P. LaCluyze, Michaël Gillon, F. Char, L. Lorenzini, Felipe Braga-Ribas, 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), Cátedra de Tecnología de la Madera. Departamento de Ingeniería Forestal (CTM-ETSIM), Universidad Politécnica de Madrid (UPM), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Observatorio Nacional [Rio de Janeiro], Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Department of Physics and Astronomy [Boone], Appalachian State University, University of North Carolina System (UNC)-University of North Carolina System (UNC), Southwest Research Institute [Boulder] (SwRI), Universidade Estadual de Ponta Grossa, Universidade Estadual de Ponta Grossa - State University of Ponta Grossa (UEPG), Observatorio Astronómico de Córdoba (OAC), Universidad Nacional de Córdoba [Argentina], Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo, Universidade Federal do Rio de Janeiro Ladeira do Pedro Antônio, 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), San Pedro de Atacama Celestial Explorations (SPACE), San Pedro de Atacama Celestial Explorations, Universidad Nacional de San Juan [Argentine] (UNSJ), Instituto de Astrofisica de Canarias (IAC), Institut d'Astrophysique et de Géophysique [Liège], Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max-Planck-Institut für Sonnensystemforschung (MPS), 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), Universidad Nacional de San Juan (UNSJ), The Royal Society, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy
Subjects: RING, Solar System, 010504 meteorology & atmospheric sciences, Ciencias Físicas, Haumea, FOS: Physical sciences, Astrophysics, 01 natural sciences, 7. Clean energy, Planet, 0103 physical sciences, QB Astronomy, Trans-Neptunian object, 010303 astronomy & astrophysics, R2C, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, QB, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Debris disk, Multidisciplinary, ~DC~, Astronomy, Radius, Planetary system, Galaxy, Astronomía, Astrophysics::Earth and Planetary Astrophysics, SATELLITES, BDC, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], SYSTEM, CIENCIAS NATURALES Y EXACTAS, Astrophysics - Earth and Planetary Astrophysics
Abstract: Hitherto, rings have been found exclusively around the four giant planets in the Solar System. Rings are natural laboratories in which to study dynamical processes analogous to those that take place during the formation of planetary systems and galaxies. Their presence also tells us about the origin and evolution of the body they encircle. Here we report observations of a multichord stellar occultation that revealed the presence of a ring system around (10199) Chariklo, which is a Centaur-that is, one of a class of small objects orbiting primarily between Jupiter and Neptune-with an equivalent radius of 124â â 9â kilometres (ref. 2). There are two dense rings, with respective widths of about 7 and 3 kilometres, optical depths of 0.4 and 0.06, and orbital radii of 391 and 405 kilometres. The present orientation of the ring is consistent with an edge-on geometry in 2008, which provides a simple explanation for the dimming of the Chariklo system between 1997 and 2008, and for the gradual disappearance of ice and other absorption features in its spectrum over the same period. This implies that the rings are partly composed of water ice. They may be the remnants of a debris disk, possibly confined by embedded, kilometre-sized satellites. © 2014 Macmillan Publishers Limited. Fil: Braga Ribas, F.. Observatório Nacional; Brasil Fil: Sicardy, B.. Universite Pierre et Marie Curie; Francia Fil: Ortiz, J.L.. Consejo Superior de Investigaciones Científicas; España Fil: Snodgrass, C.. Max Planck Institute for Solar System Research; Alemania Fil: Roques, F.. Universite Pierre et Marie Curie; Francia Fil: Vieira Martins, R.. Centre National de la Recherche Scientifique; Francia. Universidade Federal do Rio de Janeiro; Brasil Fil: Camargo, J.I.B.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Assafin, M.. Universidade Federal do Rio de Janeiro; Brasil Fil: Duffard, R.. Consejo Superior de Investigaciones Científicas; España Fil: Jehin, E.. Université de Liège; Bélgica Fil: Pollock, J.. Appalachian State University; Estados Unidos Fil: Leiva, R.. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; Chile Fil: Emilio, M.. Universidade Estadual de Ponta Grossa; Brasil Fil: MacHado, D.I.. Universidade Estadual Do Oeste Do Pará; Brasil Fil: Colazo, C.. Universidad Nacional de Córdoba; Argentina. Ministerio de Educación de la Provincia de Córdoba; Argentina Fil: Lellouch, E.. Universite Pierre et Marie Curie; Francia Fil: Skottfelt, J.. University of Copenhagen; Dinamarca. Geological Museum; Dinamarca Fil: Gillon, M.. Université de Liège; Bélgica Fil: Ligier, N.. Universite Pierre et Marie Curie; Francia Fil: Maquet, L.. Universite Pierre et Marie Curie; Francia Fil: Benedetti Rossi, G.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Gomes, A. Ramos. Universidade Federal do Rio de Janeiro; Brasil Fil: Kervella, P.. Universite Pierre et Marie Curie; Francia Fil: Monteiro, H.. Instituto de Física e Química; Brasil Fil: Sfair, R.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Moutamid, M. El. Universite Pierre et Marie Curie; Francia. Centre National de la Recherche Scientifique; Francia Fil: Tancredi, G.. Observatorio Astronómico Los Molinos; Uruguay. Universidad de la República; Uruguay Fil: Spagnotto, J.. Observatorio El Catalejo la Pampa; Argentina Fil: Maury, A.. San Pedro de Atacama Celestial Explorations; Chile Fil: Morales, N.. Consejo Superior de Investigaciones Científicas; España Fil: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico ; Argentina Fil: Roland, S.. Observatorio Astronómico Los Molinos; Uruguay Fil: Ceretta, A.. Universidad de la República; Uruguay. Observatorio del IPA; Uruguay Fil: Gu, S.-H.. Chinese Academy of Sciences; República de China Fil: Wang, X.-B.. Chinese Academy of Sciences; República de China Fil: Harpsøe, K.. University of Copenhagen; Dinamarca. Geological Museum; Dinamarca Fil: Rabus, M.. Universidad Católica de Chile; Chile. Pontificia Universidad Católica de Chile; Chile. Max Planck Institute for Astronomy; Alemania Fil: Manfroid, J.. Université de Liège; Bélgica Fil: Opitom, C.. Université de Liège; Bélgica Fil: Vanzi, L.. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; Chile Fil: Mehret, L.. Universidade Estadual de Ponta Grossa; Fil: Lorenzini, L.. Polo Astronômico Casimiro Montenegro Filho; Brasil Fil: Schneiter, E.M.. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Iate-conicet; Argentina Fil: Melia, R.. Universidad Nacional de Córdoba; Argentina Fil: Lecacheux, J.. Universite Pierre et Marie Curie; Francia Fil: Colas, F.. Centre National de la Recherche Scientifique; Francia Fil: Vachier, F.. Centre National de la Recherche Scientifique; Francia Fil: Widemann, T.. Universite Pierre et Marie Curie; Francia Fil: Almenares, L.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Sandness, R.G.. San Pedro de Atacama Celestial Explorations; Chile Fil: Char, F.. Universidad de Antofagasta; Chile Fil: Perez, V.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Lemos, P.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Martinez, N.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Jørgensen, U.G.. Universidad de Copenhagen; Dinamarca Fil: Dominik, M.. University of St. Andrews; Reino Unido Fil: Roig, F.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Reichart, D.E.. University of North Carolina; Estados Unidos Fil: Lacluyze, A.P.. University of North Carolina; Estados Unidos Fil: Haislip, J.B.. University of North Carolina; Estados Unidos Fil: Ivarsen, K.M.. University of North Carolina; Estados Unidos Fil: Moore, J.P.. University of North Carolina; Estados Unidos Fil: Frank, N.R.. University of North Carolina; Estados Unidos Fil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina
Published: 2014

27. Analysis of 25 mutual eclipses and occultations between the Galilean satellites observed from Brazil in 2009

Author: H. S. Gaspar, J. P. S. Carvalho, R. Vieira-Martins, Felipe Braga-Ribas, Rafael Sfair, Marcelo Assafin, Andre Izidoro, P. M. Pires dos Santos, A. Dias-Oliveira, Julio Camargo, Othon C. Winter, R. C. Domingos, L. A. G. Boldrin, D. N. da Silva Neto, Jarbas Cordeiro Sampaio, Observatorio Nacional [Rio de Janeiro], 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), 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), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), ECLIPSE 2015, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Faculdade de Ciencias da Universidade de Lisboa, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, Galilean moons, Jupiter, symbols.namesake, Phase angle (astronomy), Space and Planetary Science, Limb darkening, Planet, 0103 physical sciences, symbols, Natural satellite, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Eclipse
Abstract: International audience; The light curves of mutual eclipses and occultations between the natural satellites of a planet allow us to obtain high-precision position and relative motion from differential photometry, enough to detect weak orbital disturbing forces, such as tidal forces. The observations are made during the equinoxes of the planet.We studied 25 light curves observed in Brazil during the 2009 campaign of the Galilean satellites’ mutual phenomena. A narrow-band filter centred at 890 nm was used, strongly attenuating the Jupiter's scattered light. We fitted the occultation and eclipse light curves using semi-analytical models that take into account the gradual decrease of light over the shadow, the solar limb darkening and the solar phase angle. The Oren–Nayar reflexive model was used to map the inhomogeneous light scattering on the surface of the satellites. For the first time it is used in a work about mutual events. Here, we include the study that made us decide for this model.We measured the impact parameter, relative velocity and central instant with average precisions of 7.46 km (2.2 mas), 0.08 km s−1 (0.02 mas s−1) and 0.42 s (6.13 km), respectively. The fit precision of the normalized light-curve fluxes ranged between 0.4 and 4.4 per cent.
Published: 2013

28. Astrometric results of observations of mutual occultations and eclipses of the Saturnian satellites in 2009

Author: D. L. Gorshanov, O. Dechambre, Ricard Casas, A. Sergeev, A. Murphy, Brian Loader, G. Dourneau, F. Colas, A. Kurenya, A. Farmakopoulos, Marcelo Assafin, V. Kozlov, Julio Camargo, J. F. Le Campion, A. Dias-Oliveira, P. Valdes Sada, D. N. da Silva Neto, V. Tsamis, X. Zhang, D. Gault, J. Lecacheux, N. V. Emelyanov, Dave Herald, Apostolos A. Christou, Felipe Braga-Ribas, A. Massalle, R. Vieira-Martins, Jean-Eudes Arlot, T. George, N. Parakhin, Maksim V. Andreev, C. Schnabel, Valery Lainey, Alexandre Roman-Lopes, M. Mc Brien, 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), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), 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), Observatorio Nacional/MCT, Observatório Nacional/MCT, Observatório do Valongo, Universidade Federal do Rio de Janeiro Ladeira do Pedro Antônio, Universidade Estadual da Zona Oeste (UEZO), Universidade Estadual da Zona Oeste, M2A 2012, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), International Occulting and Timing Association (IOTA), International Occulting and Timing Association, Pulkovo Observatory, Russian Academy of Sciences [Moscow] (RAS), Canberra Astronomical Society, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-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)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB)
Subjects: 010504 meteorology & atmospheric sciences, planets and satellites: dynamical evolution and stability, Context (language use), Ephemeris, 01 natural sciences, Geocentric coordinates, Photometry (optics), 0103 physical sciences, occultations, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Astrometry, Position angle, Light curve, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Space and Planetary Science, astrometry, Astrophysics::Earth and Planetary Astrophysics, Right ascension, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], catalogs
Abstract: Context. The photometry of mutual occultations and eclipses of natural planetary satellites can be used to infer very accurate astrometric data. This can be achieved by processing the light curves of the satellites observed during international campaigns of photometric observations of these mutual events. Aims. This work focuses on processing the complete database of photometric observations of the mutual occultations and eclipses of the Uranian satellites made during the international campaign in 2007. The final goal is to derive new accurate astrometric data. Methods. We used an accurate photometric model of mutual events that explicitly depends on parameters that these accurate observations should be sensitive to, including the albedos of the satellites. Our original method is applied to derive astrometric data in relative positions from photometric observations of mutual occultations and eclipses of the Uranian satellites. Results. We process the 41 light-curves obtained during the international campaign of photometric observations of the Uranian satellites in 2007. The root-mean-square (rms) of the residuals “observations minus calculations” (O‐C) with respect to theory for the best 34 observations are equal to 10.3 and 17.7 mas in right ascension and declination, respectively. For five observations only the position angle was derived. Topocentric or heliocentric angular differences for satellites pairs were obtained from 25 central instant offsets between observation and theory during the time period from May 4, 2007 to January 4, 2008. Conclusions. The rms of the residuals is from 10 to 20 mas that corresponds in situ to 10 to 20 km. These mutual event observations appear to be the most accurate astrometric ground-based observations of the major Uranian satellites to-date and should be used for dynamical purposes.
Published: 2012

29. A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

Author: W. J. B. Corradi, G. P. Tozzi, D. N. da Silva Neto, S. Pastor, A. Castro, R. Gil Hutton, Petr Kubánek, P. Santos-Sanz, Felipe Braga-Ribas, L. Cuesta, L. Gutiérrez, E. Lellouch, M. T. Eibe, S. Saravia, R. Vieira Martins, H. Hernández-Toledo, Jean Manfroid, C. Jacques, A. Ramos Gomes, I. de la Cueva, A. Milone, Marcelo Emilio, Juan Fabregat, Stefano Mottola, F. Roques, Martin Jelínek, José M. Madiedo, E. García Melendo, D. Weaver, M. Cebrián, Pilar Montañés-Rodríguez, Audrey Thirouin, A. Ullán, Iain A. Steele, Wilson Reis, Roberto Vázquez, J. Lecacheux, Michaël Gillon, A. J. Castro-Tirado, Marcelo Assafin, Jose Luis Ortiz, Alain Maury, Alfredo Sota, J.A. de los Reyes, C. Harlingten, Bruno Sicardy, Emmanuel Jehin, V. Peris, Alejandro Oscoz, Daniel Hestroffer, G. Muler, R. Sanchez-Ramirez, Nicolás Morales, Alexandre Humberto Andrei, François Colas, Thomas Widemann, F. Organero, Julio Camargo, Fabio P. Santos, S. Pedraz, Rene Duffard, Raoul Behrend, 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 Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, San Pedro de Atacama Celestial Explorations (SPACE), San Pedro de Atacama Celestial Explorations, Complejo Astronómico El Leoncito [San Juan] (CASLEO), Universidad Nacional de Córdoba [Argentina]-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad Nacional de San Juan (UNSJ)-Universidad Nacional de la Plata [Argentine] (UNLP), Observatório Nacional/MCT, 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), Observatório do Valongo, Universidade Federal do Rio de Janeiro Ladeira do Pedro Antônio, Universidade Estadual da Zona Oeste (UEZO), Universidade Estadual da Zona Oeste, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Caisey Harlingten Observatory, Geneva Observatory, University of Geneva [Switzerland], German Aerospace Center (DLR), Fundació Privada Observatori Esteve Duran, Institut de Ciencies de l'Espai [Barcelona] (ICE-CSIC), Observatorio Astronomico de Valencia, Universitat de València (UV), Facultad de Ciencias Experimentales, Universidad de Huelva, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatorio astronómico de La Hita, Observatorio de la Murta, Centro Astronómico Hispano Alemán, Observatorio de Calar Alto (CAHA), Sociedad Malagueña de Astronomía, Centro Cultural José María Gutiérrez Romero, Astroimagen, Observatorio Nazaret, Liverpool JMU, Instituto de Astrofisica de Canarias (IAC), Observatório Astronomico Christus, Colégio Christus, Observatório CEAMIG-REA, Instituto de Ciências Exatas, Departamento de Física, Universidade Federal de Minas Gerais, Instituto Nacional de Pesquisas Espaciais (INPE), Ministério da Ciência, Tecnologia e Inovação, Universidade Estadual de Ponta Grossa, Universidade Estadual de Ponta Grossa - State University of Ponta Grossa (UEPG), Instituto de Astronomía, Universidad Nacional Autónoma de México (UNAM), Universidad Nacional de Córdoba [Argentina]-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad Nacional de San Juan [Argentine] (UNSJ)-Universidad Nacional de la Plata [Argentine] (UNLP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Genève = University of Geneva (UNIGE), and Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Ciencias Físicas, Astronomical unit, Dwarf planet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Orbital eccentricity, Astrophysics, no utilizado, 01 natural sciences, 7. Clean energy, Occultation, dwarf planet, Atmosphere, 0103 physical sciences, Trans-Neptunian object, 010303 astronomy & astrophysics, Eris, 0105 earth and related environmental sciences, Physics, Multidisciplinary, biology, Pluto, Astronomy, biology.organism_classification, Astronomía, 13. Climate action, CIENCIAS NATURALES Y EXACTAS, albedo
Abstract: The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1ĝ€‰au is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 ut. The event is consistent with a spherical shape for Eris, with radius 1,163±6 kilometres, density 2.52±0.05 grams per cm 3 and a high visible geometric albedo,. No nitrogen, argon or methane atmospheres are detected with surface pressure larger than about 10,000 times more tenuous than Pluto's present atmosphere. As Pluto's radius is estimated to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun. © 2011 Macmillan Publishers Limited. All rights reserved. Fil: Sicardy, B.. Universite Pierre et Marie Curie; Francia. Institut Universitaire de France; Francia Fil: Ortiz, J.L.. Consejo Superior de Investigaciones Científicas; España Fil: Assafin, M.. Universidade Federal do Rio de Janeiro; Brasil Fil: Jehin, E.. Université de Liège; Bélgica Fil: Maury, A.. San Pedro de Atacama Celestial Explorations; Chile Fil: Lellouch, E.. Universite Pierre et Marie Curie; Francia Fil: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico ; Argentina Fil: Braga Ribas, F.. Universite Pierre et Marie Curie; Francia. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Colas, F.. Universite Pierre et Marie Curie; Francia Fil: Hestroffer, D.. Universite Pierre et Marie Curie; Francia Fil: Lecacheux, J.. Universite Pierre et Marie Curie; Francia Fil: Roques, F.. Universite Pierre et Marie Curie; Francia Fil: Santos-Sanz, P.. Universite Pierre et Marie Curie; Francia Fil: Widemann, T.. Universite Pierre et Marie Curie; Francia Fil: Morales, N.. Consejo Superior de Investigaciones Científicas; España Fil: Duffard, R.. Consejo Superior de Investigaciones Científicas; España Fil: Thirouin, A.. Consejo Superior de Investigaciones Científicas; España Fil: Castro-Tirado, A.J.. Consejo Superior de Investigaciones Científicas; España Fil: Jelínek, M.. Consejo Superior de Investigaciones Científicas; España Fil: Kubánek, P.. Consejo Superior de Investigaciones Científicas; España Fil: Sota, A.. Consejo Superior de Investigaciones Científicas; España Fil: Sánchez-Ramírez, R.. Consejo Superior de Investigaciones Científicas; España Fil: Andrei, A.H.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil. Universidade Federal do Rio de Janeiro; Brasil Fil: Camargo, J.I.B.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil. Universidade Federal do Rio de Janeiro; Brasil Fil: Da Silva Neto, D.N.. Centro Universitário Estadual Da Zona Oeste; . Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Gomes Jr., A. Ramos. Universidade Federal do Rio de Janeiro; Brasil Fil: Martins, R. Vieira. Universite Pierre et Marie Curie; Francia. Universidade Federal do Rio de Janeiro; Brasil. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Gillon, M.. Université de Liège; Bélgica Fil: Manfroid, J.. Université de Liège; Bélgica Fil: Tozzi, G.P.. Osservatorio Astrofisico di Arcetri; Italia Fil: Harlingten, C.. Caisey Harlingten Observatory; Reino Unido Fil: Saravia, S.. San Pedro de Atacama Celestial Explorations; Chile Fil: Behrend, R.. Universidad de Ginebra; Suiza Fil: Mottola, S.. German Aerospace Center; Alemania Fil: Melendo, E. García. Universitat Autònoma de Barcelona; España. Consejo Superior de Investigaciones Científicas; España Fil: Peris, V.. Universidad de Valencia; España Fil: Fabregat, J.. Universidad de Valencia; España Fil: Madiedo, J.M.. Universidad de Huelva; España Fil: Cuesta, L.. Consejo Superior de Investigaciones Científicas; España Fil: Eibe, M.T.. Consejo Superior de Investigaciones Científicas; España Fil: Ullán, A.. Consejo Superior de Investigaciones Científicas; España Fil: Organero, F.. Observatorio astronómico de La Hita; España Fil: Pastor, S.. Observatorio de la Murta; España Fil: De Los Reyes, J.A.. Observatorio de la Murta; España Fil: Pedraz, S.. Centro Astronómico Hispano Alemán; España Fil: Castro, A.. Centro Cultural José María Gutiérrez Romero; España Fil: De La Cueva, I.. Astroimagen; España Fil: Muler, G.. Observatorio Nazaret; España Fil: Steele, I.A.. Liverpool JMU; Reino Unido Fil: Cebrián, M.. Instituto Astrofisico de Canarias; Fil: Montañés-Rodríguez, P.. Instituto Astrofisico de Canarias; España Fil: Oscoz, A.. Instituto Astrofisico de Canarias; España Fil: Weaver, D.. Observatório Astronomico Christus; Brasil Fil: Jacques, C.. Observatório CEAMIG-REA; Brasil Fil: Corradi, W.J.B.. Universidade Federal do Minas Gerais; Brasil Fil: Santos, F.P.. Universidade Federal do Minas Gerais; Brasil Fil: Reis, W.. Universidade Federal do Minas Gerais; Brasil Fil: Milone, A.. Instituto Nacional de Pesquisas Espaciais; Brasil Fil: Emilio, M.. Universidade Estadual de Ponta Grossa; Brasil Fil: Gutiérrez, L.. Universidad Nacional Autónoma de México; México Fil: Vázquez, R.. Universidad Nacional Autónoma de México; México Fil: Hernández Toledo, H.. Universidad Nacional Autónoma de México; México
Published: 2011

30. Precise predictions of stellar occultations by Pluto, Charon, Nix, and Hydra for 2008-2015

Author: Marcelo Assafin, Bruno Sicardy, Leslie A. Young, Felipe Braga-Ribas, A. H. Andrei, D. N. da Silva Neto, R. Vieira Martins, Julio Camargo, Observatório do Valongo, Universidade Federal do Rio de Janeiro, Observatório Nacional/MCTI, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Southwest Research Institute, and Centro Universitário Estadual da Zona Oeste
Subjects: Physics, Proper motion, Stellar mass, Astronomy, Astronomy and Astrophysics, Astrometry, Astrophysics, Ephemeris, Occultation, Star catalogue, Pluto, Stars, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Context. We investigate transneptunian objects, including Pluto and its satellites, by stellar occultations. Aims: Our aim is to derive precise, astrometric predictions for stellar occultations by Pluto and its satellites Charon, Hydra and Nix for 2008-2015. We construct an astrometric star catalog in the UCAC2 system covering Plutoarcmins sky path. Methods: We carried out in 2007 an observational program at the ESO2p2/WFI instrument covering the sky path of Pluto from 2008 to 2015. We made the astrometry of 110 GB of images with the Platform for Reduction of Astronomical Images Automatically (PRAIA). By relatively simple astrometric techniques, we treated the overlapping observations and derived a field distortion pattern for the WFI mosaic of CCDs to within 50 mas precision. Results: Positions were obtained in the UCAC2 frame with errors of 50 mas for stars up to magnitude R = 19, and 25 mas up to R = 17. New stellar proper motions were also determined with 2MASS and the USNO B1.0 catalog positions as first epoch. We generated 2252 predictions of stellar occultations by Pluto, Charon, Hydra and Nix for 2008-2015. An astrometric catalog with proper motions was produced, containing 2.24 million stars covering Plutoarcmins sky path with 30arcmin width. Its magnitude completeness is about R = 18-19 with a limit about R = 21. Based on the past 2005-2008 occultations successfully predicted, recorded and fitted, a linear drift with time in declination with regard to DE418/plu017 ephemerides was determined for Pluto and used in the current predictions. For offset (mas) = A * (t (yr) - 2005.0) + B, we find A = +30.5 ± 4.3 mas yr-1 and B = -31.5 ± 11.3 mas, with standard deviation of 14.4 mas for the offsets. For these past occultations, predictions and follow-up observations were made with the 0.6 m and 1.6 m telescopes at the Laboratório Nacional de Astrofísica/Brazil. Conclusions: Recurrent issues in stellar occultation predictions were addressed and properly overcome: body ephemeris offsets, catalog zero-point position errors and field-of-view size, long-term predictions and stellar proper motions, faint-visual versus bright-infrared stars and star/body astrometric follow-up. In particular, we highlight the usefulness of the obtained astrometric catalog as a reference frame for star/body astrometric follow-up before and after future events involving the Pluto system. Besides, it also furnishes useful photometric information for field stars in the flux calibration of observed light curves. Updates on the ephemeris offsets and candidate star positions (geometric conditions of predictions and finding charts) are made available by the group at http://www.lesia.obspm.fr/perso/bruno-sicardy
Published: 2010

31. Study of the Plutino Object (208996) 2003 AZ 84 from Stellar Occultations: Size, Shape, and Topographic Features

Author: A. Klotz, Julio Camargo, T. Hayamizu, Shashikiran Ganesh, Noah Brosch, Felipe Braga-Ribas, Avishay Gal-Yam, Paolo Tanga, J. L. Ortiz, J. Bradshaw, S. Andersson, G. Dangl, H. Tomioka, Rodrigo Leiva, Marcelo Assafin, A. Sharma, Andrea Richichi, Emmanuel Jehin, S. Sposetti, Tapas Baug, Frédéric Vachier, Zhao Ergang, T. Chandrasekhar, Zhu Liying, H. Yamamura, Shai Kaspi, Hayato Watanabe, Puji Irawati, E. Frappa, R. Naves, Eran O. Ofek, Thomas Widemann, Zouhair Benkhaldoun, Nora Morales, C. Rinner, Qian Shengbang, Alain Maury, Pablo Santos-Sanz, Ilan Manulis, Rene Duffard, Yasukazu Ikari, S. Kerr, A. Dias-Oliveira, Raoul Behrend, Jean Manfroid, Vishnu Mohan, J. Jain, Audrey Thirouin, G. Wortmann, A. Daassou, A. R. Gomes-Junior, Michaël Gillon, Hiroyuki Watanabe, Jean Lecacheux, G. Benedetti-Rossi, P. Mahasena, M. Owada, Josselin Desmars, Roberto Vieira-Martins, A. Asai, R. Garcia-Lozano, Bruno Sicardy, T. Haymes, 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), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Observatorio Nacional [Rio de Janeiro], Observatório Nacional/MCT, Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Physical Research Laboratory [Ahmedabad] (PRL), and Indian Space Research Organisation (ISRO)
Subjects: Rotation period, Chord (geometry), [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Astrophysics, Rotation, 01 natural sciences, Occultation, law.invention, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Geometric albedo, law, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Astronomy and Astrophysics, Light curve, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Amplitude, Space and Planetary Science, Hydrostatic equilibrium, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.PHYS.PHYS-DATA-AN]Physics [physics]/Physics [physics]/Data Analysis, Statistics and Probability [physics.data-an], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present results derived from four stellar occultations by the plutino object (208996) 2003~AZ$_{84}$, detected at January 8, 2011 (single-chord event), February 3, 2012 (multi-chord), December 2, 2013 (single-chord) and November 15, 2014 (multi-chord). Our observations rule out an oblate spheroid solution for 2003~AZ$_{84}$'s shape. Instead, assuming hydrostatic equilibrium, we find that a Jacobi triaxial solution with semi axes $(470 \pm 20) \times (383 \pm 10) \times (245 \pm 8)$~km % axis ratios $b/a= 0.82 \pm 0.05$ and $c/a= 0.52 \pm 0.02$, can better account for all our occultation observations. Combining these dimensions with the rotation period of the body (6.75~h) and the amplitude of its rotation light curve, we derive a density $��=0.87 \pm 0.01$~g~cm$^{-3}$ a geometric albedo $p_V= 0.097 \pm 0.009$. A grazing chord observed during the 2014 occultation reveals a topographic feature along 2003~AZ$_{84}$'s limb, that can be interpreted as an abrupt chasm of width $\sim 23$~km and depth $> 8$~km or a smooth depression of width $\sim 80$~km and depth $\sim 13$~km (or an intermediate feature between those two extremes).
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31 results on '"Felipe Braga Ribas"'

1. Pluto's Atmosphere in Plateau Phase Since 2015 from a Stellar Occultation at Devasthal

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

3. Physical characterization of double asteroid (617) Patroclus from 2007/2012 mutual events observations

4. Stellar occultations enable milliarcsecond astrometry for Trans-Neptunian objects and Centaurs

5. Volatile evolution and atmospheres of Trans-Neptunian Objects

6. The 2014-2015 Brazilian Mutual Phenomena campaign for the Jovian satellites and improved results for the 2009 events

7. First stellar occultation by the Galilean moon Europa and upcoming events between 2019 and 2021

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

9. Astrometry and Occultation predictions to Trans-Neptunian and Centaur Objects observed within the Dark Energy Survey

10. The first observed stellar occultations by the irregular satellite Phoebe (Saturn IX) and improved rotational period

11. Non-relativistic energy density functionals

12. APPROX -mutual approximations between the Galilean moons: the 2016-2018 observational campaign

13. The trans-Neptunian object (84922) 2003 VS2 through stellar occultations

14. GravityCam : wide-field high-resolution high-cadence imaging surveys in the visible from the ground

15. The future of stellar occultations by distant solar system bodies: Perspectives from the Gaia astrometry and the deep sky surveys

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

17. Results from a triple chord stellar occultation and far-infrared photometry of the trans-Neptunian object (229762) 2007 UK126

18. RESULTS FROM THE 2014 NOVEMBER 15TH MULTI-CHORD STELLAR OCCULTATION BY THE TNO (229762) 2007 UK 126

19. Pluto's Atmosphere from the 2015 June 29 Ground-Based Stellar Occultation at the Time of the New Horizons Flyby

20. James Webb Space Telescope Observations of Stellar Occultations by Solar System Bodies and Rings

21. Astrometry of the main satellites of Uranus: 18 years of observations

22. Results of two multichord stellar occultations by dwarf planet (1) Ceres

23. Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations

24. Evidence that Pluto’s atmosphere does not collapse from occultations including the 2013 May 04 event

25. Photometric and spectroscopic evidence for a dense ring system around Centaur Chariklo

26. A ring system detected around the Centaur (10199) Chariklo

27. Analysis of 25 mutual eclipses and occultations between the Galilean satellites observed from Brazil in 2009

28. Astrometric results of observations of mutual occultations and eclipses of the Saturnian satellites in 2009

29. A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

30. Precise predictions of stellar occultations by Pluto, Charon, Nix, and Hydra for 2008-2015

31. Study of the Plutino Object (208996) 2003 AZ 84 from Stellar Occultations: Size, Shape, and Topographic Features

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31 results on '"Felipe Braga Ribas"'

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