7Be detection in the 2021 outburst of RS Oph

TL;DR

This paper reports the detection of 7Be in the 2021 outburst of RS Oph, indicating recurrent novae contribute to galactic 7Li production, with detailed spectroscopic analysis estimating yields and ejected mass.

Contribution

First detection of 7Be in a recurrent nova like RS Oph, linking it to 7Li synthesis and galactic chemical evolution.

Findings

Detected 7Be with N(Be)/N(H) = 5.7 x 10^(-6)

Estimated ejected mass of 1.1 x 10^(-5) Msun

Recurrent novae may significantly contribute to galactic 7Li

Abstract

The recurrent nova RS Oph underwent a new outburst on August 8, 2021, reaching a visible brightness of V = 4.8 mag. Observations of the 2021 outburst made with the high resolution UVES spectrograph at the Kueyen-UT2 telescope of ESO-VLT in Paranal enabled detection of the possible presence of 7Be freshly made in the thermonuclear runaway reactions. The 7Be yields can be estimated in N(Be)/N(H) = 5.7 x 10^(-6), which are close to the lowest yields measured in classical novae so far. 7Be is short-lived and decays only into 7Li. By means of a spectrum taken during the nebular phase we estimated an ejected mass of about 1.1 x 10^(-5) Msun, providing an amount of about 4.4x 10^(-10) Msun of 7Li created in the 2021 event. Recurrent novae of the kind of RS Oph may synthesize slightly lower amount of 7Li per event as classical novae, but occur 10^3 times more frequently. The recurrent novae fraction is in the range of 10-30% and they could have contributed to the making of 7Li we observe today. The detection of 7Be in RS Oph provides further support to the recent suggestion that novae are the most effective source of 7Li in the Galaxy.