Mon. Not. R. Astron. Soc., 439, 954-967 (2014/March-3)
A pre-explosion optical transient event from a white dwarf merger with a giant supernova progenitor.
SABACH E. and SOKER N.
Abstract (from CDS):
We examine rare evolutionary routes of binary systems where the initially more massive primary star of M1,0 ≃ 5.5-8.5M☉ forms a white dwarf (WD), while the secondary star of 4M☉ ≲ M2, 0 < M1, 0 accretes mass from the evolved primary and later terminates as a core-collapse supernova (CCSN). In such a WD-NS (neutron star) reverse evolution a NS or a potential NS-progenitor massive core is formed after the WD. These SN explosions are likely to be preceded by strong interaction of the WD with the giant secondary's core, leading to an Intermediate-Luminosity Optical Transient (ILOT; Red Transient; Red Nova) event weeks to years before the explosion. The common envelope phase of the WD and the giant ends with a merger that forms an ILOT, or an envelope ejection that leads, after a CCSN of the giant's core, to a NS-NS or WD-NS surviving binary. The WD could suffer a thermonuclear explosion that might be observed as a Type Ia SN. Most of these CCSN and thermonuclear explosions will be peculiar. We calculate the stellar evolution of representative cases using Modules for Experiments in Stellar Astrophysics (MESA). The occurrence rate of these systems is ∼ 3-5 percent of that of CCSNe.