Rebound Shock Breakouts of Exploding Massive Stars: A MHD Void Model

TL;DR

This paper presents a self-similar MHD model of an exploding star that successfully reproduces the early X-ray light curve and spectral evolution of a specific supernova event, highlighting the role of rebound shocks.

Contribution

It introduces a novel self-similar MHD model for stellar explosions that explains observed X-ray light curves and spectral softening in supernovae.

Findings

Reproduces the early X-ray light curve of SN 2008D.

Explains spectral softening through self-similar plasma cooling.

Attributes non-thermal spectra to superpositions of thermal emissions.

Abstract

With a self-similar magnetohydrodynamic (MHD) model of an exploding progenitor star and an outgoing rebound shock and with the thermal bremsstrahlung as the major radiation mechanism in X-ray bands, we reproduce the early X-ray light curve observed for the recent event of XRO 080109/SN 2008D association. The X-ray light curve consists of a fast rise, as the shock travels into the "visible layer" in the stellar envelope, and a subsequent power-law decay, as the plasma cools in a self-similar evolution. The observed spectral softening is naturally expected in our rebound MHD shock scenario. We propose to attribute the "non-thermal spectrum" observed to be a superposition of different thermal spectra produced at different layers of the stellar envelope.