标题： 利用高分辨率传输光谱诊断热木星和极热木星的肢体不对称性 显示英文标题

标题： Diagnosing limb asymmetries in hot and ultra-hot Jupiters with high-resolution transmission spectroscopy

摘要： 由于它们可能处于潮汐锁定状态，（超）热木星的大气层应该经历强烈的空间非均匀的辐射加热。 巨大的辐射对比度和由此产生的大气环流诱导了温度和化学梯度，这些梯度可以在凌日期间在这些大气的东缘和西缘产生不对称性。 通过以高光谱分辨率观测一颗（超）热木星的传输光谱，可以通过交叉相关分析得出的净多普勒频移来恢复这些不对称性。 鉴于涉及的各种机制，识别观测到的不对称性的潜在原因并非易事。 在这项工作中，我们使用参数化和自洽的大气模型，探索了热木星和超热木星高分辨率交叉相关光谱中的不对称性来源及其诊断方法。 如果观测到了不对称性，我们发现很难将其归因于平衡化学梯度，因为许多其他过程也可能导致不对称性。 识别一种在行星大气温度范围内化学稳定的分子可以帮助建立一个“基准”，以区分其他物种中观测到的肢不对称的多种潜在原因。 鉴于CO在超热木星温度范围内的稳定性，我们将其确定为理想分子。 此外，我们发现，如果肢不对称是由晨昏线云引起的，则在凌日过程中，许多物种的蓝移应该减小。 最后，通过将我们的前向模型与Kesseli等人（2022年）的结果进行比较，我们证明将高分辨率光谱分为两个相位箱提供了在保持信噪比和解析不对称性之间的一种理想的折衷方案。 显示英文摘要

摘要： Due to their likely tidally synchronized nature, (ultra)hot Jupiter atmospheres should experience strongly spatially heterogeneous instellation. The large irradiation contrast and resulting atmospheric circulation induce temperature and chemical gradients that can produce asymmetries across the eastern and western limbs of these atmospheres during transit. By observing an (ultra)hot Jupiter's transmission spectrum at high spectral resolution, these asymmetries can be recovered -- namely through net Doppler shifts originating from the exoplanet's atmosphere yielded by cross-correlation analysis. Given the range of mechanisms at play, identifying the underlying cause of observed asymmetry is nontrivial. In this work, we explore sources and diagnostics of asymmetries in high-resolution cross-correlation spectroscopy of hot and ultra-hot Jupiters using both parameterized and self-consistent atmospheric models. If an asymmetry is observed, we find that it can be difficult to attribute it to equilibrium chemistry gradients because many other processes can produce asymmetries. Identifying a molecule that is chemically stable over the temperature range of a planetary atmosphere can help establish a ``baseline'' to disentangle the various potential causes of limb asymmetries observed in other species. We identify CO as an ideal molecule, given its stability over nearly the entirety of the ultra-hot Jupiter temperature range. Furthermore, we find that if limb asymmetry is due to morning terminator clouds, blueshifts for a number of species should decrease during transit. Finally, by comparing our forward models to Kesseli et al. (2022), we demonstrate that binning high-resolution spectra into two phase bins provides a desirable trade-off between maintaining signal to noise and resolving asymmetries.