Abstract
Type Ia supernovae (SNe Ia) are generally agreed to arise from
thermonuclear explosions of carbon–oxygen white dwarfs. The actual
path to explosion, however, remains elusive, with numerous plausible
parent systems and explosion mechanisms suggested. Observationally, SNe
Ia have multiple subclasses, distinguished by their light curves and
spectra. This raises the question of whether these indicate that
multiple mechanisms occur in nature or that explosions have a large but
continuous range of physical properties. We revisit the idea that normal
and 91bg-like SNe can be understood as part of a spectral sequence in
which changes in temperature dominate. Specifically, we find that a
single ejecta structure is sufficient to provide reasonable fits of both
the normal SN Ia SN 2011fe and the 91bg-like SN 2005bl, provided that
the luminosity and thus temperature of the ejecta are adjusted
appropriately. This suggests that the outer layers of the ejecta are
similar, thus providing some support for a common explosion mechanism.
Our spectral sequence also helps to shed light on the conditions under
which carbon can be detected in premaximum SN Ia spectra—we find
that emission from iron can “fill in” the carbon trough in
cool SNe Ia. This may indicate that the outer layers of the ejecta of
events in which carbon is detected are relatively metal-poor compared to
events in which carbon is not detected.
Original language | English |
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Pages (from-to) | 15 |
Journal | The Astrophysical Journal |
Volume | 846 |
Issue number | 1 |
DOIs | |
Publication status | Published - 01 Sept 2017 |
Keywords
- supernovae: general
- supernovae: individual: SN 2011fe
- SN 2005bl