Detection of the Supercycle in V4140 Sagittarii: First Eclipsing ER Ursae Majoris-like Object

TL;DR

This paper reports the discovery of V4140 Sgr as the first eclipsing ER UMa-like dwarf nova, with a very short supercycle and outburst behavior explained by its ER UMa-like nature and high inclination.

Contribution

It identifies V4140 Sgr as the first eclipsing ER UMa-like object, providing insights into its supercycle, outburst behavior, and implications for thermal-tidal instability models.

Findings

Supercycle of 69.7 days established

V4140 Sgr is the first eclipsing ER UMa-like dwarf nova

Outburst behavior explained by ER UMa-like nature and high inclination

Abstract

We observed the deeply eclipsing SU UMa-type dwarf nova V4140 Sgr and established the very short supercycle of 69.7(3) d. There were several short outbursts between superoutbursts. These values, together with the short orbital period (0.06143 d), were similar to, but not as extreme as, those of ER UMa-type dwarf novae. The object is thus the first, long sought, eclipsing ER UMa-like object. This ER UMa-like nature can naturally explain the high (apparent) quiescent viscosity and unusual temperature profile in quiescence, which were claimed observational features against the thermal-tidal instability model. The apparently unusual outburst behavior can be reasonably explained by a combination of this ER UMa-like nature and the high orbital inclination and there is no need for introducing mass transfer bursts from its donor star.