Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations
Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations
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2017 年 10 月 5 日恒星掩星和之前观测对海卫一大气结构和季节变化的限制
DOI：
10.1051/0004-6361/202141443
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发表时间：
2022
影响因子：
6.5
通讯作者：
B. Downs
中科院分区：
文献类型：
--
作者：
J. Oliveira;B. Sicardy;A. R. Gomes;J. L. Ortiz;D. F. Strobel;T. Bertrand;F. Forget;E. Lellouch;J. Desmars;D. B'erard;A. Doressoundiram;J. Lecacheux;Rodrigo Leiva;E. Meza;F. Roques;D. Souami;T. Widemann;P. Santos;N. Morales;R. Duffard;E. Fern'andez;A. Castro‐Tirado;F. Braga;B. Morgado;M. Assafin;J. Camargo;R. Vieira;G. Benedetti;S. Santos;M. Banda;F. Quispe;C. Pereira;F. Rommel;G. Margoti;A. Dias;F. Colas;J. Berthier;S. Renner;R. Hueso;S. P'erez;A. S'anchez;J. F. Rojas;W. Beisker;M. Kretlow;D. Herald;D. Gault;K. Bath;H. Bode;E. Bredner;K. Guhl;T. Haymes;E. Hummel;B. Kattentidt;O. Klos;A. Pratt;B. Thomé;C. Avdellidou;K. Gazeas;E. Karampotsiou;L. Tzouganatos;E. Kardasis;A. Christou;E. Xilouris;I. Alikakos;A. Gourzelas;A. Liakos;V. Charmandaris;M. Jel'inek;J. vStrobl;A. Eberle;K. Rapp;B. Gahrken;B. Klemt;S. Kowollik;R. Bitzer;M. Miller;G. Herzogenrath;D. Frangenberg;L. Brandis;I. Putz;V. Perdelwitz;G. Piehler;P. Riepe;K. Poschinger;P. Baruffetti;D. Cenadelli;J. Christille;F. Ciabattari;R. D. Luca;D. Alboresi;G. Leto;R. Z. Sánchez;P. Bruno;G. Occhipinti;L. Morrone;L. Cupolino;A. Noschese;A. Vecchione;C. Scalia;R. L. Savio;G. Giardina;S. Kamoun;R. Barbosa;R. Behrend;M. Spano;É. Bouchet;M. Cottier;L. Falco;S. Gallego;L. Tortorelli;S. Sposetti;J. Sussenbach;F. Abbeel;P. Andr'e;M. Llibre;F. Pailler;J. Ardissone;M. Boutet;J. Sanchez;M. Bretton;A. Cailleau;V. Píč;L. Granier;R. Chauvet;M. Conjat;J. Dauvergne;O. Dechambre;P. Delay;Marc Delcroix;L. Rousselot;Jade Ferreira;P. Machado;P. Tanga;J. Rivet;E. Frappa;M. Irzyk;F. Jabet;M. Kaschinski;A. Klotz;Y. Rieugnie;A. Klotz;O. Labrevoir;D. Lavandier;D. Walliang;A. Leroy;S. Bouley;S. Lisciandra;J. Coliac;F. Metz;D. Erpelding;P. Nougayrede;T. Midavaine;M. Miniou;S. Moindrot;P. Morel;B. Reginato;E. Reginato;J. Rudelle;B. Trégon;R. Tanguy;J. David;W. Thuillot;D. Hestroffer;G. Vaudescal;D. B. Aissa;Z. Grigahcene;D. Briggs;S. Broadbent;P. Denyer;N. J. Haigh;N. Quinn;G. Thurston;S. Fossey;C. Arena;M. Jennings;J. Talbot;S. Alonso;A. Reche;V. Casanova;E. Briggs;R. Iglesias;J. Ib'anez;M. C. Mart'in;H. Gonz'alez;J. Garc'ia;J. Marchant;I. Ordóñez;P. Martorell;J. Salamero;F. Organero;L. Ana;F. Fonseca;V. Peris;O. Brevia;A. Selva;C. Perelló;V. Cabedo;R. Gonccalves;M. Ferreira;F. M. Dias;A. Daassou;K. Barkaoui;Z. Benkhaldoun;M. Guennoun;J. Chouqar;E. Jehin;C. Rinner;J. Lloyd;M. E. Moutamid;C. Lamarche;J. Pollock;D. Caton;V. Kouprianov;B. Timerson;G. Blanchard;B. Payet;A. Peyrot;J. Teng;J. Franccoise;B. Mondon;T. Payet;C. Boissel;M. Castets;W. Hubbard;R. Hill;H. Reitsema;O. Mousis;L. Ball;G. Neilsen;S. Hutcheon;Kaitlan Lay;P. Anderson;M. Moy;M. Jonsen;I. Pink;R. Walters;B. Downs
上下文。2017年10月5日，海王星的主要卫星Triton在欧洲、北非和美国观测到了一次恒星掩星。我们从这次事件中得出了90条光曲线，其中42条产生了中央fl火山灰探测。目标。我们的目标是限制Triton的大气结构和自旅行者2号纪元(1989)以来其大气压力的季节变化。我们还从中心的fl灰分分析中得出了低层大气的形状。方法：研究方法。我们使用阿贝尔反演和直接射线跟踪代码来提供fi8公里到∼190公里高度范围内的密度、压力和温度曲线，对应于从9微巴到几个纳米巴的压力水平。结果。(I)在1400公里(47公里高度)的参考半径处发现压力为1.18±0.03微巴。(2)对旅行者2号无线电科学掩星的新分析表明，这与1989年获得的气压向下到地面气压的外推是一致的。(Iii)对1989年至2017年期间的掩星进行的一项调查表明，1990年代报告的地面气压的增加可能是真实的，但值得商榷，因为很少有高的S/N光曲线和可用于再分析的数据。所分析的挥发性输送模型支持地表压力的适度增加，2005-2015年左右的最大值不高于23微巴。1995-1997年和2017年观察到的压力似乎与这里提出的波动运输模型相互不一致。(4)中心的fl火山灰结构没有显示出大气扭曲的证据。我们发现在8公里高度附近大气的表观扁平度的上限为0.0011。(fi)
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 ∼ 8 km to ∼ 190 km, corresponding to pressure levels from 9 µ bar down to a few nanobars. Results. (i) A pressure of 1.18 ± 0.03 µ 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 µ 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.