The Long-time Evolution of Accretion-Induced Collapse of White Dwarfs to Neutron Stars

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Speaker :  
Dr. Eirini Batziou (Max Planck Institute for Astrophysics, Germany)
Location :  
2nd Floor Seminar Room & Online
Date :  

Time : 

Abstract :

The accretion-induced collapse (AIC) of white dwarfs (WDs) is an alternative scenario to neutron star (NS) formation; apart from the core collapse of massive stars, it can act as a site for heavy-element nucleosynthesis and is a candidate for fast-evolving transients. 
We present the results of the first long-time evolution of AICs from the onset of the white dwarf collapse to the homologous expansion of the ejecta for a set of six models, including non-rotating and rotating WDs with different initial masses, spin rates, and angular momentum profiles. Our simulations determine characteristic properties of the AIC events, such as ejecta masses and energy, ejecta geometry,  the neutron-to-proton ratio, entropy, and the properties of NSs born from collapsing WDs. We demonstrated that AICs produce neutrino-driven outflows and are sub-energetic events with low explosion energies of ~ 0.1 Bethe. Our models yield outflows with a total ejecta mass of ~0.001 solar masses and a large spread in the neutron-to-proton ratio distribution that can have implications for the r-process nucleosynthesis.