标题： 热木星HD 149026b凌星大气的探测 显示英文标题

标题： The Search for an Atmospheric Signature of the Transiting Exoplanet HD 149026b

摘要： HD 149026b是一颗短周期、土星质量的行星，它经过一颗富金属恒星前面。通过光度测定确定的该行星半径与其他已知凌星行星相比异常小，并且其重元素核心显然占总行星质量的约70%。为了建模罗西特-麦克劳克林效应，在凯克望远镜上获取了凌星前后的时序光谱。在这里，我们利用这些观测结果，对凌星内和凌星外获得的光谱进行微分对比，以寻找来自行星大气中中性原子锂和钾的特征信号。没有检测到2%水平的信号；因此，我们对这些原子的柱密度设定了上限。 显示英文摘要

摘要： HD 149026b is a short-period, Saturn-mass planet that transits a metal-rich star. The planet's radius, determined by photometry, is remarkably small compared to other known transiting planets, with a heavy-element core that apparently comprises ~70% of the total planet mass. Time-series spectra were obtained at Keck before and during transit in order to model the Rossiter-McLaughlin effect. Here we make use of these observations to carry out a differential comparison of spectra obtained in and out of transit to search for signatures of neutral atomic lithium and potassium from the planet atmosphere. No signal was detected at the 2% level; we therefore place upper limits on the column density of these atoms.