Thesis Topic: Probing the past history of star formation through red supergiants

Thesis Supervisor: Fernando Comerón

Abstract

Red supergiants of spectral types K and M are the descendants of the hot, luminous O and early B-type stars once they have left the main sequence and entered the helium-burning phase. Being among the brightest stars in the infrared makes them easily identifiable, and their ages at that evolutionary stage make them useful as probes of past massive star formation in OB associations long after the associations have dispersed in space. The excellent astrometry of the upcoming Gaia Data Release 3 will make it possible to reconstruct trajectories and estimate birthplaces of these stars up to several kiloparsecs away from the Sun, giving the opportunity of investigating the history of recent massive star formation in the local galactic disk over timescales several times longer than those accessible using the O-type stars observable at present. The purpose of the PhD project is to produce an extensive census of red supergiants in our Galaxy assisted by the Gaia data and the results of several other surveys, identify shortcomings requiring new observations with ESO telescopes, and apply the results to investigate the star formation history over the entire lifetime of giant molecular clouds and their evolution during and after their passage through the galactic spiral arms.