Photometric variability of the nova-like object V380 Oph in 1976-2016

TL;DR

This study presents a 40-year light curve of V380 Oph, revealing its classification as a VY Scl-type variable with specific brightness episodes and periodicities linked to superhumps and disc precession.

Contribution

It combines diverse observational data to analyze long-term variability and identifies new periodicities related to the system's accretion disc behavior.

Findings

Identification of two low-brightness episodes confirming VY Scl classification

Detection of two periodicities possibly linked to superhumps and disc precession

Agreement between different photographic measurement methods

Abstract

We combined photographic, photoelectric and CCD observations of the nova-like variable V380 Oph to get a light curve spanning the time range of 40 years. While the typical high-state brightness of V380 Oph was R~14.5, two low-brightness episodes identified in 1979 (B_pg~17.5) and 2015 (R~19) confirm its classification as a VY Scl-type "anti-dwarf nova". The Fourier period analysis of photoelectric and CCD V and B observations obtained in 2002-16 revealed the presence of two periods 0.148167d and 4.287d, that may be associated with negative superhumps and disc precession. We also compared measurements obtained with the iris micro-photometer and flatbed scanner at the same plates and found an agreement within the expected accuracy of photographic photometry.