Ages, Kinematics, and Chemistry of Stellar Populations

恒星族群的年龄、运动学和化学

• 批准号: 9221237
• 负责人: Bruce Carney
• 金额: $ 28.86万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-03-01 至 1998-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9221237&HistoricalAwards=false
• 关键词: Ages; Kinematics; Chemistry; Stellar; Populations

Ages, Kinematics, and Chemistry of Stellar Populations. The relationships of the Galaxy's stellar populations remain a puzzle. Kinematically biased programs, even with the detailed modeling to be completed during the award period, do justice to hot populations like the Galactic halo but not to cool disk populations. Thus, a program begun in 1991 will be carried to completion in the solar neighborhood wherein Dr. Carney, together with Dr. John Laird at Bowling Green University, will identify several thousand G dwarf stars, then determine accurate radial velocities and metallicities to test the discrete versus continuum models of the thick disk and thin disk populations. The study and use of synthetic spectra will be extended into the infrared in anticipation of future chemistry versus kinematics studies throughout the disk. Recent age estimates of the oldest globular clusters are inconsistent with the expansion ages implied by the popularly favored large Hubble constants, independent of the local mass density parameter. For more accurate ages of globular clusters, more work is required on the abundance of oxygen in halo stars. A test of the halo distance scale will be performed using a maximum likelihood statistical parallax analysis of 500 metal-poor stars. Lithium abundances in single halo stars with a wide range of effective temperature will be derived to probe Big Bang nucleosynthesis.

恒星群的年龄、运动学和化学。银河系恒星数量之间的关系仍然是一个谜。运动学上有偏差的程序，即使在奖励期间完成了详细的建模，对像银河晕这样的热星系群也能做到公正，但对冷星系盘群却不行。因此，一项始于1991年的计划将在太阳附近完成，卡尼博士将与鲍灵格林大学的约翰·莱尔德博士一起，确定几千颗G矮星，然后确定精确的径向速度和金属丰度，以测试厚盘和薄盘人口的离散与连续模型。合成光谱的研究和使用将扩展到红外，以预测未来整个磁盘的化学与运动学研究。最近对最古老的球状星团的年龄估计与广受欢迎的大哈勃常数所暗示的膨胀年龄不一致，该常数独立于局部质量密度参数。为了更准确地确定球状星团的年龄，需要对晕星中氧的丰度进行更多的研究。将对500颗缺金属恒星进行最大似然统计视差分析，以测试光晕距离尺度。在广泛的有效温度范围内的单晕恒星中，锂丰度将被导出来探测大爆炸核合成。