Low state in the post-nova V1315 Aql

Taichi Kato

Published 2023-05-20Version 1

Using Asteroid Terrestrial-impact Last Alert System (ATLAS) and Zwicky Transient Facility (ZTF) data, I found that the SW Sex star V1315 Aql entered a low state early in 2023. As far as I know, this is the first such an event since the discovery of this object with observations dating back to 1948. This object is renowned for its nova shell and the nova explosion was estimated to occur 500-1200 yr ago, although no direct detection of a nova eruption was present in the historical record. The present low state probably occurred as the mass-transfer rate from the nova-irradiated secondary decreased secularly. The present low state would provide an opportunity to study the secondary in detail, which has been hampered by the luminous accretion disk in the past. I also provide the recent light curve of the classical nova LV Vul, which now shows high and low states 50 yr after the nova eruption.