论文标题
带有反射光谱的外球星大气的多轨道和多带表征
Multi-orbital-phase and multi-band characterization of exoplanetary atmospheres with reflected light spectra
论文作者
论文摘要
从空间中广泛分离的系外行星的直接成像将获得其反射光谱并测量大气特性。先前的计算表明，轨道相的变化会导致光谱信号，但是是否可以使用该信号来表征大气。我们使用迄今为止最逼真的模拟器姐妹模拟了对星际效果的观测值47 UMA B，以估计由于残留的星光，太阳闪闪发光和外生光的光线而导致的不确定性。然后，我们使用贝叶斯检索算法Exorel $^\ re $来确定使用罗马或HABEX样望远镜观察的大气特性的约束，并比较在多个轨道相或多个波长频段中观察的策略。在类似罗马的望远镜上，带有600-800 nm的$ \ sim20 \％$带宽，检索发现了一个退化的情况，其气体丰富度较低，并且比真相更深或更深。在800-1000 nm中以相同的集成时间并因此有效地消除了这种退化的溶液，在800-1000 nm中重复观察到800-1000 nm的第二美元\％$波长频段，在800-1000 nm中重复观察结果。使用HABEX样望远镜的单个观察结果将对气体丰度和云特性产生高精度的限制，而没有退化的情况。这些结果通常也适用于具有类似波长覆盖范围和S/N的冠状动脉的高对比度光谱法，并且可以帮助设计波长带宽以及将来的系外行星直接成像实验的观察计划。
Direct imaging of widely separated exoplanets from space will obtain their reflected light spectra and measure atmospheric properties. Previous calculations have shown that a change in the orbital phase would cause a spectral signal, but whether this signal may be used to characterize the atmosphere has not been shown. We simulate starshade-enabled observations of the planet 47 Uma b, using the to-date most realistic simulator SISTER to estimate the uncertainties due to residual starlight, solar glint, and exozodiacal light. We then use the Bayesian retrieval algorithm ExoReL$^\Re$ to determine the constraints on the atmospheric properties from observations using a Roman- or HabEx-like telescope, comparing the strategies to observe at multiple orbital phases or in multiple wavelength bands. With a $\sim20\%$ bandwidth in 600 - 800 nm on a Roman-like telescope, the retrieval finds a degenerate scenario with a lower gas abundance and a deeper or absent cloud than the truth. Repeating the observation at a different orbital phase or at a second $20\%$ wavelength band in 800 - 1000 nm, with the same integration time and thus degraded S/N, would effectively eliminate this degenerate solution. Single observation with a HabEx-like telescope would yield high-precision constraints on the gas abundances and cloud properties, without the degenerate scenario. These results are also generally applicable to high-contrast spectroscopy with a coronagraph with a similar wavelength coverage and S/N, and can help design the wavelength bandwidth and the observation plan of exoplanet direct imaging experiments in the future.
