Date/Time
Date(s) - 26/01/2011
3:20 pm - 4:20 pm

Title: Stellar Mergers in Low-mass Interacting Binary Stars

Speaker: Dr. Michael Politano, Marquette University

Institute: Marquette University

Location: ABB 102

Description:

The number of binary stars in our galaxy equals or exceeds the number of single stars. Some of these binary stars are close enough to each other for significant tidal interactions to occur. One scenario involving such tidal interactions involves a giant star (tens to hundreds of times greater than the radius of our Sun) engulfing its companion. Because of dynamical friction, the companion spirals in towards the core (center) of the giant star. This tidally-induced phase of evolution is known as the “common envelope (CE)” phase and is believed to play an essential role in the formation of short-period binaries containing compact objects (such as white dwarfs or neutron stars). There are two possible outcomes of the CE phase. If enough orbital energy is released into the envelope to unbind it before the companion spirals into the core, the result is a short-period binary containing the core of the giant star (which becomes a white dwarf) and the companion. If there is insufficient energy in the orbit to unbind the envelope, the companion and the giant will merge. In this talk, I describe the results of theoretical calculations designed to simulate the present-day population of such merged objects within the disk of our galaxy.