Studying the Inner Regions of Young Binary Systems using Near-Infrared Interferometry

行星在年轻恒星周围的气体+尘埃盘中形成。一旦行星获得了足够的质量，它们就会在盘面结构上打开缝隙，就像在HL Tau这样的系统中可能观察到的那样。为了探测打开缺口的行星本身，人们进行了各种搜索，但收效甚微。因此，需要从观测到的缝隙几何形状间接推断假设的缝隙开口体的性质。关键的下一步是在相互作用的物体的性质，特别是它们的质量和轨道是众所周知的情况下，研究潮汐相互作用。这种情况可以在年轻的近距离双星系统中找到，在这些系统中，一颗低质量的恒星伴星以几百天到几年的时间尺度绕着一颗质量更大的中央恒星运行。这些伴星可以截断圆盘或打开缝隙，探测与行星形成类似的动力学过程。可以使用径向速度测量和红外干涉观测来测量伴星的三维轨道和质量。同时，潮汐开启间隙的几何形状现在可以在更长的波长上测量，例如使用VLTI中红外干涉仪和ALMA亚毫米干涉仪。这个PHD项目的目的是研究一个年轻的双星系统的红外/亚毫米干涉术的样本，得出3-D轨道，并测量伴星对盘结构的潮汐影响。我们将约束基本的恒星和盘参数，并导出伴星的吸积率，为模拟行星形成盘中的盘清理和吸积过程提供一个重要的基准。

Planets form in the gas+dust discs around young stars. Once the planets have gained sufficient mass they open gaps in the disc surface structure, as might be observed in systems such as HL Tau. Various searches have been conducted in order to detect the gap-opening planets themselves, but with limited success. Therefore, the properties of the putative gap-opening bodies need to be inferred indirectly from the observed gap geometry. The essential next step is to study tidal interactions in cases where the properties of the interacting bodies, in particular their mass and orbit, are well-known. Such cases can be found in young close binary systems, where a low-mass stellar companion orbits a more massive central star on timescales of a few hundred days to a few years. These companions can either truncate the disc or open gaps, probing similar dynamical processes as in planet formation. The 3-D orbits and masses of the companions can be measured using radial velocity measurements and infrared interferometric observations. At the same time, the geometry of the tidally-opened gap can now be measured at longer wavelengths, for instance with VLTI mid-infrared interferometry and ALMA sub-millimetre interferometry.The aim of this PhD project is to study a sample of young binary systems with infrared/sub-millimeter interferometry, to derive 3-D orbits, and to measure the tidal influence that the companions exerts on the disc structure. We will constrain fundamental stellar & disc parameters and derive the accretion rate onto the companion star, providing an important benchmark for modelling disc clearing and accretion processes in planet-forming discs.