标题： 热木星的朋友III：红外光谱搜索低质量恒星伴星 显示英文标题

标题： Friends of Hot Jupiters III: An Infrared Spectroscopic Search for Low-Mass Stellar Companions

摘要： 附近场星的调查表明恒星双星很常见，但人们对这些伴星可能对行星形成和演化产生的影响知之甚少。 “热木星的朋友”项目使用三种互补的技术来寻找已知行星宿主恒星的恒星伴星：径向速度监测、自适应光学成像和近红外光谱。 本文中，我们检查了五十颗宿主短周期气体巨行星恒星的高分辨率K波段红外光谱。 我们利用光谱拟合来搜索由于目标星光谱中存在冷型恒星伴星而导致的混合线，我们对温度在3500-5000K之间、大多数系统中投影分离小于100AU的伴星敏感。 我们确认了八个具有候选低质量伴星的系统，其中包括一个在我们的AO成像巡天中独立探测到的伴星。 对于有径向速度加速的系统，光谱上的非检测排除了高倾角轨道上恒星伴星存在的可能性。 我们用这些数据对小投影分离处的恒星双星分数设定了上限，并表明候选伴星群体与场星一致，也与我们在之前AO巡天中检测到的宽分离伴星群体一致。 我们没有发现光谱恒星伴星倾向于位于短周期气体巨行星的偏心和/或错位轨道系统的证据。 显示英文摘要

摘要： Surveys of nearby field stars indicate that stellar binaries are common, yet little is known about the effects that these companions may have on planet formation and evolution. The Friends of Hot Jupiters project uses three complementary techniques to search for stellar companions to known planet-hosting stars: radial velocity monitoring, adaptive optics imaging, and near-infrared spectroscopy. In this paper, we examine high-resolution K band infrared spectra of fifty stars hosting gas giant planets on short-period orbits. We use spectral fitting to search for blended lines due to the presence of cool stellar companions in the spectra of our target stars, where we are sensitive to companions with temperatures between 3500-5000 K and projected separations less than 100 AU in most systems. We identify eight systems with candidate low-mass companions, including one companion that was independently detected in our AO imaging survey. For systems with radial velocity accelerations, a spectroscopic non-detection rules out scenarios involving a stellar companion in a high inclination orbit. We use these data to place an upper limit on the stellar binary fraction at small projected separations, and show that the observed population of candidate companions is consistent with that of field stars and also with the population of wide-separation companions detected in our previous AO survey. We find no evidence that spectroscopic stellar companions are preferentially located in systems with short-period gas giant planets on eccentric and/or misaligned orbits.