טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentEfrat Sabach
SubjectTransient Event from a Core-WD Merger
DepartmentDepartment of Physics
Supervisor Full Professor Soker Noam
Full Thesis textFull thesis text - English Version


Abstract

We examine rare evolutionary routes of binary systems where the initially more massive primary star of M1,0 ?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 reverse evolution a neutron star (NS) or a massive core that is a potential progenitor of a NS is formed after the WD. These SN explosions are likely to be preceded by strong interaction of the WD with the core of the giant secondary, 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). We estimate that the systems studied here occur at a rate of 3 − 5 percent of that of CCSNe.