太阳系天体的氘氢比(D/H比)是揭示其形成历史的重要线索。本文将海王星大气模型与双子座近红外光谱仪(GNIRS)高光谱分辨率观测数据进行拟合,确定了甲烷在红外H波段($\sim$ 1.6 μm)吸收的D/H比。该模型是使用我们的辐射转移软件VSTAR(Versatile Software for the Transfer of Atmospheric Radiation)和大气拟合软件ATMOF(Atmospheric Fitting)导出的。这项工作所使用的甲烷线清单是在过去几年中才得到的,因此可以对以前的估计进行改进。我们确定了行星盘上的一个明亮区域,并发现它对应于一个光学厚的低云。我们初步确定CH $_{\rm 3}$ D/CH $_{\rm 4}$为3.0 $\times10^{-4}$,这与Irwin等人(2014)最近使用相同模型参数和线列表但不同观测数据确定的3.0 $^{+1.0}_{-0.9}\sim\times10^{-4}$一致。这支持了海王星的原太阳冰D/H比远小于彗星的证据,并表明海王星在其目前的轨道内形成。
英文摘要:
The ratio of deuterium to hydrogen (D/H ratio) of Solar System bodies is an important clue to their formation histories. Here we fit a Neptunian atmospheric model to Gemini Near Infrared Spectrograph (GNIRS) high spectral resolution observations and determine the D/H ratio in methane absorption in the infrared H-band ($\sim$ 1.6 μm). The model was derived using our radiative transfer software VSTAR (Versatile Software for the Transfer of Atmospheric Radiation) and atmospheric fitting software ATMOF (ATMOspheric Fitting). The methane line list used for this work has only become available in the last few years, enabling a refinement of earlier estimates. We identify a bright region on the planetary disc and find it to correspond to an optically thick lower cloud. Our preliminary determination of CH$_{\rm 3}$D/CH$_{\rm 4}$ is 3.0$\times10^{-4}$, which is in line with the recent determination of Irwin et al. (2014) of 3.0$^{+1.0}_{-0.9}\sim\times10^{-4}$, made using the same model parameters and line list but different observational data. This supports evidence that the proto-solar ice D/H ratio of Neptune is much less than that of the comets, and suggests Neptune formed inside its present orbit.
Investigating potential causes for high inferred intrinsic temperatures of warm transiting Neptune and Sub-Neptune planets
University of Texas, Austin(德克萨斯大学奥斯汀分校);Massachusetts Institute of Technology(麻省理工学院);Leibniz Institute for Astrophysics Potsdam(波茨坦莱布尼茨天体物理研究所);University of Amsterdam(阿姆斯特丹大学);The Open University of Israel(以色列开放大学);Arizona State University(亚利桑那州立大学);University of California, Santa Cruz(加州大学圣克鲁兹分校);Carnegie Institution for Science(卡内基科学学会)
Beyond Equilibrium Temperature: How the Atmosphere/Interior Connection Affects the Onset of Methane, Ammonia, and Clouds in Warm Transiting Giant Planets
Contrasting C/O ratios in Uranus and Neptune from disequilibrium chemistry: A clue to distinct evolutionary pathways?
Aix-Marseille Université(艾克斯-马赛大学);Southwest Research Institute(西南研究院);Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux(波尔多大学天体物理实验室);Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité(巴黎天文台、巴黎文理研究大学、法国国家科学研究中心、索邦大学、巴黎西岱大学);University of Science and Technology of China(中国科学技术大学);Dublin Institute for Advanced Studies(都柏林高等研究所);Space Science Institute(空间科学研究所)
2001 QR$_{322}$ - an update on Neptune's first unstable Trojan companion
海王星特洛伊人是最近加入到太阳系小天体群体的一员。第一个被发现的成员2001 QR $_{322}$的轨道在发现后不久就根据对该天体的早期观测进行了研究,发现它在与太阳系的年龄相当的时间尺度上是动态稳定的。在随后几年中,随着对该物体的进一步观测,其轨道的最佳拟合解发生了变化。因此,我们在2010年对2001 QR $_{322}$的轨道进行了新的研究,发现它位于海王星特洛伊云的动态稳定区和不稳定区之间的边界,并得出结论,需要进一步观测才能确定该物体轨道的真正稳定性。在这里,我们跟进的早期工作,并提出了初步的动力学研究结果,使用更新的适合2001年QR $_{322}$的轨道。尽管2001年QR $_{322}$的轨道的精度有所提高,我们发现,最适合的解决方案仍然保持平衡的刀刃,躺在我们以前的工作中指出的稳定和不稳定的相同区域之间。今后,我们打算进行新的观测,希望能在一定程度上完善轨道,最终弄清其真实性质。
The HARPS search for southern extra-solar planets. XLVII. Five Jupiter-mass planets in long-period orbits, one highly irradiated Neptune, one brown dwarf, and five stellar binaries