Chemistry and kinematics of stars in dwarf galaxies

矮星系中恒星的化学和运动学

• 批准号: 327292-2006
• 负责人: Venn, Kimberley
• 金额: $ 2.33万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=361356
• 关键词: Chemistry; kinematics; stars; dwarf; galaxies

Are dwarf galaxies the same as the protogalactic fragments that merged to form large galaxies, as described in the hierarchical galaxy formation models?    Was the Galactic thick disk formed through disk heating by a merger at an intermediate epoch?  How similar are the star formation histories of the dwarf spheroidal galaxies to the gas rich dwarf irregular systems?    Questions such as these can now be addressed through detailed chemical analyses of the individual stars in the low-mass dwarf galaxies in the Local Group, made possible with the large 8 to 10-m class telescopes and high efficiency spectrographs.  My research involves the determination of the chemical composition of old stars in dwarf spheroidal galaxies and young stars in dwarf irregular galaxies.   Currently, comparisons of stars in dwarf galaxies with similar stars in our  Galaxy show very little in common, but we are on the verge of a breakthrough as results from the multi-object spectrographs begin to emerge.   Analyses of hundreds of stars per dwarf galaxy allow us to examine hierarchical galaxy formation, as well as test our assumptions about stellar nucleosynthesis in general.  The next generation of telescopes and instrumentation will make it possible to reach the old stars in the more isolated dwarf galaxies for the first time, which may be different from the nearby systems that we are currently able to study, as well as stars in more distant dwarf galaxies such as those orbiting the Andromeda galaxy and possibly those in the Virgo cluster.

矮星系是否与分层星系形成模型中描述的合并形成大星系的原星系碎片相同？银河系厚盘是在中间时期的合并过程中通过盘加热形成的吗？矮球状星系的恒星形成历史与富含气体的矮不规则星系的恒星形成历史有多相似？诸如此类的问题现在可以通过对本星系群中低质量矮星系中单个恒星的详细化学分析来解决，这可以通过8到10米级的大型望远镜和高效光谱仪来实现。我的研究包括测定矮球状星系中年老恒星和矮不规则星系中年轻恒星的化学成分。目前，对矮星系中的恒星与银河系中类似恒星的比较显示出很少的共同点，但随着多目标光谱仪的结果开始出现，我们即将取得突破。对每个矮星系数百颗恒星的分析使我们能够检查分层星系的形成，并测试我们对恒星核合成的一般假设。下一代望远镜和仪器将使我们有可能第一次到达更孤立的矮星系中的老恒星，这可能不同于我们目前能够研究的附近系统，以及更遥远的矮星系中的恒星，如围绕仙女座星系运行的星系，可能还有处女座星团中的恒星。