Abundances and Evolution of Stars in the Bulge of the Galaxy

银河系核球中恒星的丰度和演化

• 批准号: 9015827
• 负责人: Robert Rich
• 金额: $ 8.74万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-05-01 至 1993-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9015827&HistoricalAwards=false
• 关键词: Abundances; Evolution; Stars; Bulge; Galaxy

The heavy metal composition of the central nuclear Bulge of our Milky Way Galaxy is important to studies of the types of stars constituting both external galaxies and the first generation of stars in the disk of our Galaxy. Currently star formation is thought to proceed more rapidly in the Bulge than in the neighborhood of the Sun. A point of controversy over the last twenty years has been the question of whether strong absorption lines in the spectra of red giant stars actually reflect an enhanced abundance of heavy elements, or whether they perhaps arise as a consequence of anomalies in the structures of the atmospheres of these stars. The Principal Investigator (PI) wishes to conduct research in this area by measuring the abundance of the heavy metal elements in a selected group of Bulge red giants. This study will differ from those of the past in that high dispersion spectra will be obtained with modern solid state arrays to conduct the abundance analysis. The results will be used to estimate the mass distribution of supernovae which return nuclear-processed material into the interstellar medium. A secondary project will be to determine whether carbon-star giants (the origin of which is likewise unclear) in the Bulge have enhanced metal abundances relative to the Sun's composition.

银河系中央核球的重金属成分对于研究构成银河系外部星系的恒星类型和银河系盘中的第一代恒星具有重要意义。目前，恒星的形成被认为在凸起比在太阳附近进行得更快。在过去的二十年里，一个有争议的问题是，红巨星光谱中的强吸收线是否实际上反映了重元素丰度的增加，或者它们是否可能是由于这些恒星大气结构的异常而产生的。首席调查员(PI)希望通过测量选定的一组凸起红巨星中重金属元素的丰度来进行这方面的研究。这项研究将不同于以往的研究，因为将利用现代固态阵列获得高色散光谱来进行丰度分析。这些结果将被用来估计超新星的质量分布，这些超新星将核处理过的物质返回星际介质。第二个项目将是确定凸起中的碳星巨星(其来源同样不清楚)是否增加了相对于太阳组成的金属丰度。