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Our recent work demonstrates a correlation between the high-velocity blue edge, vedge, of the ironpeak Fe/Co/Ni H-band emission feature and the optical light curve shape of normal, transitional and sub-luminous type Ia Supernovae (SNe Ia). We explain this correlation in terms of SN Ia physics. vedge corresponds to the sharp transition between the complete and incomplete silicon burning regions in the ejecta. It measures the point in velocity space where the outer 56Ni mass fraction, XNi, falls to the order of 0.03-0.10. For a given 56Ni mass, M(56Ni), vedge is sensitive to the speci c kinetic energy Ekin(M(56Ni)=MWD) of the corresponding region. Combining vedge with light curve parameters (i.e., sBV , m15;s in B and V ) allows us to distinguish between explosion scenarios. The correlation between vedge and light-curve shape is consistent with explosion models near the Chandrasekhar limit. However, the available sub-MCh WD explosion model based on SN 1999by exhibits velocities which are too large to explain the observations. Finally, the sub-luminous SN 2015bo exhibits signatures of a dynamical merger of two WDs demonstrating diversity among explosion scenarios at the faint end of the SNe Ia population.
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This content will become publicly available on September 1, 2025
Ejecta Masses in Type Ia Supernovae—Implications for the Progenitor and the Explosion Scenario*
Abstract The progenitor system(s) as well as the explosion mechanism(s) of thermonuclear (Type Ia) supernovae are long-standing issues in astrophysics. Here we present ejecta masses and other physical parameters for 28 recent Type Ia supernovae inferred from multiband photometric and optical spectroscopic data. Our results confirm that the majority of SNe Ia showobservableejecta masses below the Chandrasekhar-limit (having a meanMej≈ 1.1 ± 0.3M⊙), consistent with the predictions of recent sub-MChexplosion models. They are compatible with models assuming either single- or double-degenerate progenitor configurations. We also recover a sub-sample of supernovae within 1.2M⊙<Mej< 1.5M⊙that are consistent with near-Chandrasekhar explosions. Taking into account the uncertainties of the inferred ejecta masses, about half of our SNe are compatible with both explosion models. We compare our results with those in previous studies, and discuss the caveats and concerns regarding the applied methodology.
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- PAR ID:
- 10542355
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- PASP
- Date Published:
- Journal Name:
- Publications of the Astronomical Society of the Pacific
- Volume:
- 136
- Issue:
- 9
- ISSN:
- 0004-6280
- Page Range / eLocation ID:
- 094201
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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