Authors:

Ashi Poorey

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About Paper:

Warm Hypergiants (WHG) are extremely luminous A-F type supergiants, approximately 20-40 times the mass of the Sun, located on the Hertzsprung—Russell diagram near the Humphreys—Davidson limit and the yellow void, where stars are thought to undergo unstable evolutionary transitions. Previous photometric studies of WHG, including work by Dorn-Wallerstein et al. [1], identified irregular brightness variations but were not sensitive to very long-period variability. This project investigates whether WHG exhibit long-term periodicity in their brightness variations with amplitudes large enough to potentially drive episodes of mass loss and evolutionary change. Twelve years of photometric data for ten WHG in the nearby galaxies M31 and M33 are analyzed using Lomb-Scargle time-series methods to search for variability on timescales from weeks to several years. The targets are grouped into at least three categories: those showing periods of several hundred days, those with periods longer than 1000 days, and those with no discernible periodic variation. These results help characterize how pulsation and episodic mass loss influence the late evolutionary stages of massive stars.

Source:

University of Illinois Urbana-Champaign

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Co-authors:

Ashi Poorey