The evolution of massive stars in the context of V838 Monocerotis

Raphael Hirschi

University of Basel, Switzerland

The aim of this paper is to look at the evolution of massive stars in order to determine whether or not the progenitor of V838 Mon may be a massive star. In the first part of this paper, the evolution of massive stars around solar metallicity is described, especially the evolution in the Hertzsprung-Russell (HR) diagram. Then, using the observational constraints, the probable
progenitors (and their evolution) are described.

Using models of single stars, no progenitor can be found amongst massive stars that can
satisfy all the observational constraints. Wolf-Rayet stars (stars with initial masses above about 30 $M_\odot$, which have lost their hydrogen rich envelopes) could explain 10 to 100 $M_\odot$ of circumstellar material but they are very luminous ($L \gtrsim 10^5\,L_\odot$). Main sequence stars crossing the HR diagram and becoming red supergiants (RSG) can have very low effective temperatures but take thousands of years to cross over. Be stars (fast rotating stars with a mass around 10 $M_\odot$), which form disk or B stars accreting matter from a binary companion of a similar mass would need to be compared in detail with the observational constraints.

In the future, there will hopefully be further observational constraints on the models coming from the mass and nature (interstellar or
circumstellar) of the material producing the light echo and from a frequency estimate of
spectacular objects such as V838 Mon.

Reference: To appear in ASP Conf. Ser.,The Nature of V838 Mon and its Light Echo, May 16-19th 2006, ed. R.L.M. Corradi and U. Munari
Status: Conference proceedings


Comments: 8 pages, 3 figures