@misc{10481/74472,
year = {2022},
month = {4},
url = {http://hdl.handle.net/10481/74472},
abstract = {Context. A stellar occultation by Neptune's main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection.

Aims. We aimed at constraining Triton's atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis.

Methods. We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range similar to 8 km to similar to 190 km, corresponding to pressure levels from 9 mu bar down to a few nanobars.

Results. (i) A pressure of 1.18 +/- 0.03 mu bar is found at a reference radius of 1400 km (47 km altitude). (ii) A new analysis of the Voyager 2 radio science occultation shows that this is consistent with an extrapolation of pressure down to the surface pressure obtained in 1989. (iii) A survey of occultations obtained between 1989 and 2017 suggests that an enhancement in surface pressure as reported during the 1990s might be real, but debatable, due to very few high S/N light curves and data accessible for reanalysis. The volatile transport model analysed supports a moderate increase in surface pressure, with a maximum value around 2005-2015 no higher than 23 mu bar. The pressures observed in 1995-1997 and 2017 appear mutually inconsistent with the volatile transport model presented here. (iv) The central flash structure does not show evidence of an atmospheric distortion. We find an upper limit of 0.0011 for the apparent oblateness of the atmosphere near the 8 km altitude.},
organization = {Portuguese Foundation for Science and Technology	SFRH/BD/131700/2017},
organization = {European Social Fund (ESF)	SFRH/BD/131700/2017},
organization = {European Research Council under the European Community's H2020 2014-2021 ERC grant	669416},
organization = {Spanish Government	SEV-2017-0709	
AYA-2017-84637-R	
AYA-RTI2018-098657-J-I00},
organization = {Junta de Andalucia	2012-FQM1776},
organization = {European Union's Horizon 2020 Research and Innovation Programme, as part of the project "Small Bodies Near and Far" (SBNAF)	687378},
organization = {Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)},
organization = {Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF)	309578/2017-5	
304544/2017-5	
401903/2016-8	
308150/2016-3	
305917/2019-6	
427700/2018-3	
310683/2017-3	
473002/2013-2},
organization = {Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)	001},
organization = {Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)	465376/2014-2	
CAPES-FAPERJ/PAPDRJ grant	E26/203.173/2016	
CAPES-PRINT/UNESP grant	88887.571156/2020-00},
organization = {Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ)	E26/111.488/2013},
organization = {Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)	2018/11239-8},
organization = {Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)	150612/2020-6},
organization = {European Union's Horizon 2020 research and innovation programme	730890},
organization = {Regional Government of the Aosta Valley},
organization = {Town Municipality of Nus},
organization = {Unite des Communes valdotaines Mont-Emilius},
organization = {Planetary Society},
organization = {Fondazione CRT-Cassa di Risparmio di Torino},
organization = {Portuguese Foundation for Science and Technology	PTDC/FISAST/29942/2017},
organization = {FEDER through COMPETE 2020	POCI010145 FEDER007672},
organization = {UK Research & Innovation (UKRI)},
organization = {Science & Technology Facilities Council (STFC)},
organization = {Fondos de Inversiones de Teruel (FITE)},
organization = {Spanish Government	AYA2015-65041P	
PID2019-109467GB-100},
organization = {Grupos Gobierno Vasco	IT1366-19},
organization = {Fonds de la Recherche Scientifique - FNRS	PDR T.0120.21},
organization = {University of Liege},
organization = {CAPES/Cofecub-394/2016-05},
publisher = {EDP},
keywords = {Methods: data analysis},
keywords = {Methods: observational},
keywords = {Planets and satellites: atmospheres},
keywords = {Planets and satellites: physical evolution},
keywords = {Techniques: photometric},
title = {Constraints on the structure and seasonal variations of Triton’s atmosphere from the 5 October 2017 stellar occultation and previous observations},
doi = {10.1051/0004-6361/202141443},
author = {Marques Oliveira, J. and Ortiz Moreno, José Luis and Santos Sanz, Pablo and Morales, N. and Duffard, René Damian and Fernández Valenzuela, Estela del Mar and Castro Tirado, Alberto Javier and Kretlow, M. and Alonso Burgos, Sergio and Román Reche, Antonio and Casanova, V.},
}