Postdoctoral Fellowship: AAPF: Cosmology with Most Massive Asymptotic Giant Branch Stars

Caroline Huang is awarded an NSF Astronomy and Astrophysics Fellowship to carry out a program of research and education at the Smithsonian Astrophysical Observatory. Huang will use large observational surveys to study the longest-period, most massive Mira variables, which are more astrophysically complex and distinct from their shorter-period counterparts.

Results from this project will be used to establish an independent and powerful new standard candle capable of checking other primary distance indicators and of improving our understanding of systematics in the local distance ladder, which is used in direct measurements of the Hubble Constant. For the education component of this project, Huang will also conduct work in concert with Wolbach Library's Project PHaEDRA and Harvard College Observatory's DASCH project to perform an interdisciplinary re-analysis of historical data and research performed by early HCO astronomers and women computers.

This research project will focus on using publically-available variable star catalogs to obtain absolute magnitude calibrations of long-period Miras using cluster parallaxes from the Milky Way and detached eclipsing binary distances from the Large and Small Magellanic Clouds. This study will also leverage the environmental differences of these three galaxies to study the effect of oxygen abundance on asymptotic giant branch star evolution and the form of the period-luminosity relation.

Over-luminous variables or sources with ambiguous classification based on the derived period-luminosity relations will be targeted for spectroscopic follow-up in order to confirm classification and identify potential hot-bottom burning, reducing systematics on the distance measurements obtained with these stars.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.