The White Dwarf Mass and the Accretion Rate of Recurrent Novae: an X-ray Perspective

TL;DR

This paper investigates the X-ray emissions of recurrent novae during quiescence to understand white dwarf masses and accretion rates, revealing a dichotomy in X-ray brightness that could help identify new RN candidates.

Contribution

It provides new insights into the X-ray characteristics of recurrent novae and proposes scenarios explaining their X-ray emission diversity.

Findings

Luminous hard X-ray sources indicate near Chandrasekhar mass white dwarfs.

Detection of hard X-ray emissions in old novae suggests potential RN candidates.

Some RNe are X-ray faint, indicating diverse accretion states or compositions.

Abstract

We present recent results of quiescent X-ray observations of recurrent novae (RNe) and related objects. Several RNe are luminous hard X-ray sources in quiescence, consistent with accretion onto a near Chandrasekhar mass white dwarf. Detection of similar hard X-ray emissions in old novae and other cataclysmic variables may lead to identification of additional RN candidates. On the other hand, other RNe are found to be comparatively hard X-ray faint. We present several scenarios that may explain this dichotomy, which should be explored further.