The Ages of Nearby A-Type Stars

许多被研究得最好的行星系统都围绕着附近的A型恒星运行，A型恒星是比太阳质量稍大的恒星。 该项目将使用格鲁吉亚州立大学的高角分辨率天文干涉仪阵列中心（CHARA）来确定这些恒星的基本属性（例如，大小和表面温度），除其他外，这将使其年龄的估计更加准确。 准确的年龄对于确定行星系统如何随时间变化至关重要。 该计划将培养一名初级天文学家（博士后研究员）和两名本科生在一个高调的科学研究领域。 项目参与者还将参加在格鲁吉亚州立大学的艰苦劳动溪观测站的公共宣传活动。 该团队将使用CHARA干涉仪阵列测量60颗附近的A型恒星。 他们将精确测量快速旋转恒星的扁圆形状，并模拟引力变暗的影响。 这些测量将提供与进化模型更准确的比较，从中可以推断质量和年龄。这些结果可以实现新的科学进步，包括测试解释快速恒星旋转的进化模型，限制一些A型恒星如何以及为什么化学上奇特的理论，碎片盘和/或行星系统进化阶段的时间戳，其中一些恒星所拥有的，以及校正更遥远的质量和年龄估计偏差的经验关系，因此，空间上无法分辨，快速旋转的A型恒星。

Many of the best studied planetary systems orbit nearby A-Type stars, which are stars that are slightly more massive than the Sun. This project will use Georgia State University's Center for High Angular Resolution Astronomy interferometer array (CHARA) to determine the fundamental properties of these stars (for example, sizes and surface temperatures) that, among other things, will enable much more accurate estimates of their age. Accurate ages are critical for determining how planetary systems change with time. This program will train a junior astronomer (a postdoctoral researcher) and two undergraduate students in a high profile area of scientific research. Project participants will also participate in public outreach activities at Georgia State University's Hard Labor Creek Observatory. The team will use the CHARA interferometer array to survey 60 nearby A-Type stars. They will precisely measure the oblate shapes of rapidly rotating stars and model the effect of gravity darkening. These measurements will provide more accurate comparisons with evolutionary models, from which masses and ages can be inferred. The results could enable new scientific advances, including tests of evolutionary models that account for rapid stellar rotation, constraints on theories for how and why some A-Type stars are chemically peculiar, a temporal stamp for the evolutionary stage of the debris disks and/or planetary systems that some of these stars harbor, and empirical relations for correcting the biases in mass and age estimates of more distant, and thus spatially unresolved, rapidly rotating A-Type Stars.