Life after eruption - V. Spectroscopy of eight candidate old novae with Gemini-South

TL;DR

This study spectroscopically analyzes eight candidate old novae, confirming five and identifying potential counterparts, revealing diverse accretion properties and system inclinations, and suggesting some as promising targets for further detailed observations.

Contribution

It provides new spectroscopic data on eight post-nova candidates, confirming five and identifying likely counterparts, with insights into their accretion states and system geometries.

Findings

Two oldest post-novae have optically thick accretion discs.

Some systems show high inclination, suitable for time-series studies.

BS Sgr is a strong candidate for an intermediate polar.

Abstract

We present the analysis of photometric and spectroscopic data on eight candidates for post-nova systems. Five post-novae, V528 Aql, HS Sge, BS Sgr, GR Sgr and V999 Sgr, are successfully recovered. We furthermore identify likely candidates for the fields of V1301 Aql, V1151 Sgr and V3964 Sgr. The spectroscopic properties of the confirmed post-novae are briefly discussed. We find that two of the oldest post-novae in our sample, GR Sgr and V999 Sgr, contain an optically thick accretion disc, and thus can be suspected to have a high mass-transfer rate, contrary to what one would expect from most models. HS Sge and V528 Aql show evidence for a (comparatively) high system inclination, which makes them attractive targets for time-series observations. Finally, the presence of particularly strong He II emission together with a small eruption amplitude suggests that BS Sgr is a good candidate for an intermediate polar.