A 70 pc-Diameter Nova Super-remnant Surrounding the Recurrent Nova RS Ophiuchi

TL;DR

This paper reports the discovery of a 70-parsec super-remnant around the recurrent nova RS Ophiuchi, supporting the idea that all recurrent novae are surrounded by large, faint structures formed by successive eruptions.

Contribution

It provides the first detailed observation of a super-remnant around RS Ophiuchi, confirming theoretical predictions about the extent of material ejected by recurrent novae.

Findings

Discovered a 70-parsec shell around RS Ophiuchi.

Estimated the super-remnant mass to be 20-200 solar masses.

Super-remnant expansion age is approximately 50-100 thousand years.

Abstract

Recurrent novae undergo thermonuclear-powered eruptions separated by less than 100 years, enabled by subgiant or red giant donors transferring hydrogen-rich matter at very high rates onto their massive white dwarf companions. The most-rapidly moving parts of envelopes ejected in successive recurrent nova events are predicted to overtake and collide with the slowest ejecta of the previous eruption, leading to the buildup of vast (~ 10 - 100 parsec) super-remnants surrounding all recurrent novae; but only three examples are currently known. We report deep narrowband imaging and spectroscopy which has revealed a ~ 70-parsec-diameter shell surrounding the frequently recurring nova RS Ophiuchi. We estimate the super-remnant mass to be ~ 20 - 200 solar masses, expanding at a few tens of km/s, with an age of order 50-100 kyr. Its extremely low surface brightness and large angular size help explain the hitherto surprising absence of nova super-remnants. Our results support the prediction that ALL recurrent novae are surrounded by similar extended structures.