Chemically Peculiar Hot Subdwarfs

总结：炽热的次矮星代表了一种罕见但寿命相对较长的星星，现在GAIA清楚地将其确定为赫兹-罗素图中的一个独特类别。大多数的表面都富含氢，可以被解释为核心氦燃烧的恒星，在一个紧密的双星相互作用中失去了大部分的表面层。大约10%-20%有富氦表面，必须来自其他演化通道。我们正在用SALT和LAMOST对这些恒星进行光谱调查，并发现了各种各样的奇异天体，包括重金属亚矮星，逃逸星，极端第二星族星和新的极端氦星。学生将接管SALT调查数据的日常操作和简化，并将学习光谱分析技术，以检查单个恒星，以有助于更全面地了解恒星演化的后期阶段。

Summary: Hot subdwarfs represent a rare but relatively-long-lived class of star, now clearly identified by GAIA as a distinct class in the Hertzsprung-Russell diagram. The majority have hydrogen-rich surfaces and can be accounted for as core-helium burning stars which lost most of their surface layers in a close binary-star interaction. About 10 - 20 per cent have helium rich surfaces, and must come from other evolution channels. We are carrying out a spectroscopic survey of these stars with SALT and also with LAMOST, and are discovering an extraordinary variety of exotic objects, including heavy-metal subdwarfs, runaway stars, extreme population II stars, and new extreme helium stars. The student will take over the day-to-day operation and reduction of the SALT survey data, and will learn techniques of spectral analysis to examine individual stars, in order to contribute to a more comprehensive picture of the late stages of stellar evolution.