2007/10/08 by Anthony L. Piro, Lars Bildsten · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1086/524189
Accepted for publication in The Astrophysical Journal, 5 pages, 4 figures
arxiv created 2007/10/08 · openalex publication_date 2008/02/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
Prior to the incineration of a white dwarf (WD) that makes a Type Ia supernova (SN Ia), the star "simmers" for ~1000 yr in a convecting, carbon-burning region. We have found that weak interactions during this time increase the neutron excess by an amount that depends on the total quantity of carbon burned prior to the explosion. This contribution is in addition to the metallicity ( Z ) dependent neutronization through the 22 Ne abundance (as studied by Timmes, Brown, & Truran). The main consequence is that we expect a "floor" to the level of neutronization that dominates over the metallicity contribution when Z / Z ☉ ≲ 2/3, and it can be important for even larger metallicities if substantial energy is lost to neutrinos via the convective Urca process. This would mask any correlations between SN Ia properties and galactic environments at low metallicities. In addition, we show that recent observations of the dependences of SNe Ia on galactic environments make it clear that metallicity alone cannot provide for the full observed diversity of events.