Recurrent Novae - A Review

TL;DR

This review discusses recent multi-wavelength observations of recurrent novae, focusing on the enigmatic T Pyx, and explores the complexities of nova envelope ejection and its implications for stellar evolution.

Contribution

It provides a comprehensive synthesis of recent observational data on recurrent novae, highlighting the complexities of envelope ejection and proposing potential links between recurrent and classical novae.

Findings

T Pyx exhibits unusually high accretion rates.

Nova envelope ejection is more complex than traditional models.

Possible connection between recurrent and classical novae.

Abstract

In recent years, recurrent nova eruptions are often observed very intensely in wide range of wavelengths from radio to optical to X-rays. Here I present selected highlights from recent multi-wavelength observations. The enigma of T Pyx is at the heart of this paper. While our current understanding of CV and symbiotic star evolution can explain why certain subset of recurrent novae have high accretion rate, that of T Pyx must be greatly elevated compared to the evolutionary mean. At the same time, we have extensive data to be able to estimate how the nova envelope was ejected in T Pyx, and it turns to be a rather complex tale. One suspects that envelope ejection in recurrent and classical novae in general is more complicated than the textbook descriptions. At the end of the review, I will speculate that these two may be connected.