Speaker
Description
The community has reached a consensus that thermonuclear supernovae are explosions of white dwarfs. But it is not known how an isolated white dwarf can explode. Most explosion scenarios involve white dwarfs in a binary to explain thermonuclear explosions. But the exact nature of the companion star, and the explosion mechanisms are not well understood. White dwarf supernovae are also important source of Fe group elements, so it is important to study their impact on galactic chemical evolution.
Observational campaigns over the years have strengthened the need for invoking multiple progenitor scenarios. This lack of understanding impacts their use as standardizable candles. We present a detailed case study of SN 2022xlp, a low-luminosity Type Ia supernova exhibiting prominent carbon features at early phases. Our analysis includes optical light curves and spectroscopic observations. The observed properties, supported by spectroscopic modeling, are consistent with an explosion of a carbon–oxygen white dwarf. We compare SN 2022xlp with other thermonuclear supernovae, particularly the 2002cx-like (Type Iax) subclass, to place it in the broader context of SN Ia diversity. 2002cx-like supernovae are crucial for understanding the diversity of thermonuclear explosions, as they likely arise from failed or partial deflagrations and provide key constraints on progenitor systems and explosion physics.
A key focus of this work is the carbon feature at $\lambda6580$, located adjacent to the Si,{\sc ii} $\lambda6355$ doublet. In normal and high-velocity SNe Ia, these features are often blended, complicating their interpretation. However, the relatively low expansion velocities in SN 2022xlp result in less blended spectral features, providing a unique opportunity to probe the presence and role of unburned carbon. Furthermore, we investigate the ionization states across a sample of SNe Ia and find that their wide luminosity range leads to significant differences in ionization and excitation conditions. We would discuss the connections of the plasma conditions to the progenitor scenario.
| Participate the oral/poster presentation award competition | Yes |
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