TAPIR Seminar

In person: 370 Cahill. To Join via Zoom: 868 5298 8404

ABSTRACT: Type Ia supernovae result from the explosion of a carbon-oxygen white dwarf accreting mass from a binary companion, whose nature remains elusive. In the double detonation scenario, a donor star transfers helium-rich material to an accretor white dwarf, leading to the detonation of the helium shell and the subsequent detonation of the carbon core of the accretor.  I will describe new models of mass transfer from a partially degenerate helium white dwarf onto a carbon-oxygen white dwarf, and highlight their likely outcome as double-detonation type Ia supernovae. 

Following the explosion, the donor star leaves at its orbital velocity of over 1000 km/s. To date, seven such hypervelocity stars have been discovered from Gaia data. They show inflated radii and metal-polluted atmospheres. I will present new 3D hydrodynamical simulations modeling the interaction between the donor star and the supernova ejecta, and show that the post-shock properties of the donor star agree well with one of the best-studied hypervelocity stars. I will also discuss how much material is stripped from the donor and where it resides within the expanding supernova ejecta.