A Monte Carlo Simulation of OB Star Binary Evolution
Session 56 -- Stellar Evolution and Clusters
Oral presentation, Wednesday, 10:30-12:00, Durham Room

## [56.01] A Monte Carlo Simulation of OB Star Binary Evolution

J. L. Terman (Columbia U., Northwestern U.)

We have developed a model that tests the idea that supernovas in massive binary systems can produce the high velocity populations of runaway OB stars, High Mass X-ray Binaries (HMXB's), Be stars and radio pulsars seen in the Galaxy. Our model takes a representative population of OB stars (8 - 40 ${\rm M}_{\odot}$) and evolves them off the main-sequence. In short period binary systems, the primary will fill its Roche lobe and transfer its mass to the secondary conservatively for as long as the secondary's Rochex lobe does not overflow. Our model has three parameters: (1) the final mass ratio ($m_1/m_2$) of the system after conservative mass transfer stops, (2) the minimum core mass that will explode as a type II supernova, (3) the magnitude of the kick velocity given to the remnant neutron star after the explosion. We find that the final mass transfer ratio affects the kinematics of the HMXB's, runaway OB and Be stars studied significantly. The magnitude of the kick velocity strongly affects the number of HMXB's and Be stars and also greatly alters the distribution of pulsar velocities produced. The velocities of the runaway O stars and HMXB's produced by our model agree well with observations as do the calculated X-ray luminosities of O stars with compact companions from wind-driven accretion.