论文标题
从2017年10月5日出色的仿生和先前的观察结果开始,特里顿大气的结构和季节性变化的限制
Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations
论文作者
论文摘要
Neptune的主要卫星特里顿(Triton)的出色掩星在2017年10月5日从欧洲,北非和美国观察到。我们从这个事件中得出了90条光曲线,其中42个产生了中央闪光检测。 我们的目的是限制Triton的大气结构和自Voyager 2 Epoch(1989)以来其大气压的季节变化。我们还通过中央闪光分析得出了下部大气的形状。我们使用ABEL倒置和直接射线追踪代码来提供高度,压力和温度曲线的高度范围$ \ sim $ \ sim $ 8 km至$ \ sim $ 190 km,对应于9μbar的压力水平,从9μbar降至几种纳米。 结果。 (i)在1400 km(47 km海拔47 km)的参考半径下发现1.18 $ \ pm $0.03μbar的压力。 (ii)对Voyager 2无线电科学掩盖的新分析表明,这与1989年的压力向降低到表面压力的推断是一致的。(iii)对1989年至2017年之间获得的偷除的调查表明,在1990年代报道的表面压力增加,但由于很少有可能是在1990年代所报道的,但由于很少的高级/n级别的速度可用于降低速度和数据范围。分析的挥发性传输模型支持表面压力中等增加,最大值左右在2005-2015左右不超过23μbar。 1995年至1997年和2017年观察到的压力似乎与此处介绍的挥发性运输模型相互不一致。 (iv)中央闪光结构没有显示大气失真的证据。我们发现在8 km高度附近的大气的明显底漆上,上限为0.0011。
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. 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. We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range $\sim$8 km to $\sim$190 km, corresponding to pressure levels from 9 μbar down to a few nanobars. Results. (i) A pressure of 1.18$\pm$0.03 μbar 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 μbar. 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.