The recurrent nova RS Oph: A possible scenario for type Ia supernovae

TL;DR

This paper models the recurrent nova RS Oph, suggesting it hosts a white dwarf near the Chandrasekhar mass that could eventually explode as a type Ia supernova, supported by gamma-ray emission analysis.

Contribution

It provides theoretical models indicating RS Oph's white dwarf is close to Chandrasekhar mass and may become a supernova, with gamma-ray emission analysis ruling out radioactive decay origins.

Findings

White dwarf mass near Chandrasekhar limit

Potential supernova in 10^5-10^7 years

Gamma-ray emission not from radioactive decay

Abstract

The recurrent nova RS Oph experienced an outburst in 2006, 21 years after its previous explosion in 1985, as expected. It was observed at almost all wavelengths, and important information about its properties is still being extracted. We present theoretical models of the explosion of this fascinating object, which indicate that the mass of the accreting white dwarf should be very close to the Chandrasekhar mass, to allow for such a short recurrence period. In addition, since models suggest that this nova ejects less mass than it accretes, it is an excellent candidate for a thermonuclear supernova explosion, in about $10^5-10^7$ years from now. We also analyze the emission of soft gamma-rays by RS Oph detected with the BAT instrument onboard Swift, and with the PCA onboard RXTE. We rule out that this emission has its origin in radioactive decays in the expanding nova envelope.