Massive stars (with masses more than 8 solar masses) play a major role in the evolution of their host galaxies. Via stellar winds, they deposit large amounts of momentum and energy into their surroundings and enrich the interstellar medium with chemically processed material, providing the cradles for next generations of stars and planets. Despite their great importance, stellar evolution theory is most uncertain for massive stars. In particular, the amount of mass lost during certain transition phases with sudden mass ejections is yet unknown.
Our research focuses on different stages in the evolution of massive stars, among them are yellow and blue hypergiants, B[e] supergiants, interacting binaries such as symbiotic stars, and various types of peculiar objects. We study their variability, trying to link it to stellar pulsations and phases of enhanced mass loss and eruptions, based mainly on the analysis of optical and infra-red spectroscopic and photometric time series. We obtain important insights into the structure, kinematics, and evolution of the ejected material around the stars from modern imaging techniques.
The observed behaviour of our targets is modelled using state-of-the-art radiative transfer models of stellar atmospheres, winds, and circumstellar material.
Osalus Euroopa Kosmoseagentuuri (ESA) Gaia missioonis
Indrek Kolka has been part of the Gaia Data Processing and Analysis Consortium (DPAC) since 2002.
In 2011–2013, researchers were co-partners of the ESA PECS project "Emission-Line Star Classification in the Gaia Catalogue" (I. Kolka, L. Leedjärv, T. Eenmäe, T. Tuvikene).
In 2014–2015, we continued working on the ESA PECS project "Algorithms for Mapping Galactic Structures with Gaia and Euclid".
Astrophysical observatrory instruments in Tõravere include