Long-Period Variables - Pulsating AGB stars in the Gaia Era

  • Date: –15:00
  • Location: Ångströmlaboratoriet, Lägerhyddsvägen 1 Hiorter's room (Å73101)
  • Lecturer: Michele Trabucchi, University of Padua, Italy
  • Organiser: Division of Astronomy and Space Physics, Department of Physics and Astronomy
  • Contact person: Sofia Ramstedt
  • Seminarium

Abstract:

Long-period variables (LPVs) are easily detectable representative of the Asymptotic Giant Branch (AGB) evolutionary phase, characterized by wide ranges of amplitudes (millimag to several magnitudes) and periods (from a few days to > 1000 days). Their observed variability can be used to measure stellar masses and radii, to constrain stellar physics, and to trace and characterize intermediate age stellar populations. Through its connection with mass-loss and dust formation, the pulsation of the most evolved AGB stars can help to improve our understanding of the mechanisms that lead to the death of these stars, and to study the chemical evolution of galaxies. LPVs follow several period-luminosity relations, that represent promising distance estimators, especially thanks to the large-amplitude variability and intrinsic high brightness of AGB stars. The Gaia mission's data release 2 is providing new ways to probe the properties of LPVs, while the use of updated pulsation models, combined with stellar population synthesis, is revealing a new complexity in their period-luminosity diagram. Covering these topics, I will discuss how the study of LPVs is changing, the problems we are facing, and, what can we expect from the future.