Fundamental parameters of hot subdwarf stars from the Tycho-Gaia sample

热演化恒星的基本参数，如质量和半径，受到的约束很差。热亚矮星（sdO/B）是一种致密的氦星，是热演化恒星中的重要星族。它们在紫外线下支配着古老的恒星种群，是研究恒星演化中各种特殊事件的关键对象，如恒星和行星的相互作用或Ia型超新星的祖先。从2016年开始，我们将能够确定这些恒星的基本参数并研究它们的形成。为了实现这一目标，我们必须改进这些特殊物体的大气模型，并使用高质量的同质数据集最大限度地减少系统性。为了这个项目，我们在艾萨克·牛顿望远镜的IDS摄谱仪上呆了五个晚上。在此提议资金支付此次观测运行的费用。

The fundamental parameters of hot evolved stars, like masses and radii, are poorly constrained. Hot subdwarf stars (sdO/B) are compact helium stars and constitute an important population of hot evolved stars. They dominate old stellar populations in the ultraviolet and are key objects to study peculiar events in stellar evolution as diverse as the interaction of stars and planets or the progenitors of type Ia supernovae. With accurate distances from the Gaia mission available from 2016 we will be able to determine the fundamental parameters of those stars and study their formation. To achieve this, we have to improve the atmospheric models for those peculiar objects and minimize systematics using a homogeneous dataset of high quality. We were granted five nights with the IDS spectrograph at the Isaac Newton telescope for this project. Here propose funds to cover the expenses of this observing run.