标题： JWST天气报告：检索SIMP-0136上的温度变化、极光加热和静态云层覆盖情况 显示英文标题

标题： The JWST Weather Report: retrieving temperature variations, auroral heating, and static cloud coverage on SIMP-0136

摘要： SIMP-0136是一个T2.5棕矮星，其年轻的年龄（$200\pm50$~Myr）和低质量（$15\pm3$~M$_{\rm Jup}$）使其成为直接成像系外行星群体的理想类比。具有2.4小时的周期，它在红外和无线电波段都被发现是变化的，这分别被归因于云层覆盖的变化和极光的存在。为了量化驱动这种变化的大气状态变化，我们获得了覆盖SIMP-0136完整旋转的一系列时间序列光谱，使用了JWST上的NIRSpec/PRISM和MIRI/LRS。我们使用petitRADTRANS进行了一系列时间分辨的大气反演，以测量温度结构、化学成分和云量的变化。我们推断出在SIMP-0136的10 mbar以上存在约250 K的热反转，并提出这种反转是由于极光将能量沉积到高层大气中所致。为了确定哪些参数驱动观测到的光谱变化，进行了统计检验。主要贡献来自于10 mbar以下压力处温度剖面的变化，这导致有效温度从1243 K变化到1248 K。这种变化的有效温度也与CO2和H2S丰度的变化相关，而所有其他化学物质则被认为在整个大气中是均匀的。需要斑状硅酸盐云来拟合观测到的光谱，但云层特性并未发现随经度系统性变化。这项工作描绘了一个L/T过渡天体的图景，其中主要的变异性机制是磁性和热力学性质，而不是由于不均匀的云层覆盖。 显示英文摘要

摘要： SIMP-0136 is a T2.5 brown dwarf whose young age ($200\pm50$~Myr) and low mass ($15\pm3$~M$_{\rm Jup}$) make it an ideal analogue for the directly imaged exoplanet population. With a 2.4 hour period, it is known to be variable in both the infrared and the radio, which has been attributed to changes in the cloud coverage and the presence of an aurora respectively. To quantify the changes in the atmospheric state that drive this variability, we obtained time-series spectra of SIMP-0136 covering one full rotation with both NIRSpec/PRISM and the MIRI/LRS on board JWST. We performed a series of time-resolved atmospheric retrievals using petitRADTRANS in order to measure changes in the temperature structure, chemistry, and cloudiness. We inferred the presence of a ~250 K thermal inversion above 10 mbar of SIMP-0136 at all phases, and propose that this inversion is due to the deposition of energy into the upper atmosphere by an aurora. Statistical tests were performed in order to determine which parameters drive the observed spectroscopic variability. The primary contribution was due to changes in the temperature profile at pressures deeper than 10 mbar, which resulted in variation of the effective temperature from 1243 K to 1248 K. This changing effective temperature was also correlated to observed changes in the abundances of CO2 and H2S, while all other chemical species were consistent with being homogeneous throughout the atmosphere. Patchy silicate clouds were required to fit the observed spectra, but the cloud properties were not found to systematically vary with longitude. This work paints a portrait of an L/T transition object where the primary variability mechanisms are magnetic and thermodynamic in nature, rather than due to inhomogeneous cloud coverage.