The Ages of Nearby A-Type Stars

Georgia State University Research Foundation, Inc., Atlanta GA

Investigators

Abstract

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.