A SYSTEMATIC SURVEY OF CHEMICAL ABUNDANCES AMONG A-TYPE STARS BASED ON HIGH DISPERSION SPECTROSCOPIC DATA

本研究项目基于1990年多明尼安天体物理天文台获得的大量早期型恒星的高色散数字光谱数据。最初的动机是使用均匀技术对许多恒星进行系统的分析。该项目的第一阶段是专门利用工作站和IRAF软件开发一个数据分析系统。数据分析系统完成后，在样本恒星中发现了几个有趣的天体，并对这些天体进行了详细的研究。第一个物体是一颗特殊的恒星HR 1094，它表现出异常强烈的铬（Cl）和钴（Co）谱线。它还显示了汞（Hg）和铂（Pt）的谱线，并且不属于任何已知的CP星群。第二个天体是一颗强磁星HR 7575。作为分析这颗恒星复杂光谱的第一步，已经编制了一份观测谱线识别表。对一颗“正常”的A3V狮子座95星的光谱进行了详细分析，结果发现这颗恒星是一颗缺金属的恒星。狮子座是先前发现的缺金属恒星中温度最低的恒星。这颗恒星的化学丰度结果将对缺金属恒星的理论解释提供约束。对其他恒星的分析目前正在进行中，最终结果将在不久的将来公布。

This research project is based on a large body of high dispersion digital spectroscopic data of early type stars obtained at the Dominion Astrophysical Observatory in 1990. The initial motivation has been to carry out a systematic analyzes of many stars using a homogeneous technique. The first stage of the project was devoted to develop a system of data analysis using a Work Station and the IRAF software. After the completion of the data analysis system, several interesting objects have been discovered among the sample stars and detailed studies of these objects were carried out.The first object was a peculiar star HR 1094 exhibiting amomalously strong lines of chroline (Cl) and cobalt (Co). It also shows lines of mercury (Hg) and platinum (Pt) and does not belong to any previously known group of CP stars. The second object was a strong magnetic star HR 7575. As an initial step of analyzing the complex spectrum of this star, an identification list of observed lines has been prepared.The spectrum of a 'normal' A3V star 95 Leo has been analyzed in detail and the star turned out to be a metal deficient star. 95 Leo is the coolest star among previously detected metal deficient stars. The result of chemical abundances of this star will give a constraint on the theoretical interpretation of metal deficient stars.Analysis of other stars are now in progress and the final results will be published in the near future.