The eclipsing novalike cataclysmic variable CRTS SSS100505 J093417-174421

TL;DR

This study characterizes the eclipsing novalike cataclysmic variable CRTS SSS100505 J093417-174421, revealing its orbital parameters, accretion disk structure, and emission features through combined photometric and TESS data analysis.

Contribution

First detailed analysis of the eclipsing novalike CV CRTS SSS100505 J093417-174421 using eclipse mapping and TESS data, identifying disk asymmetries and spiral shock features.

Findings

Orbital period of 0.16329188 days.

Detection of tidally-induced spiral shock arms.

Accretion disk size varies with wavelength.

Abstract

Time-resolved optical photometry, complemented by TESS data and long-term survey light curves, reveals that the transient object CRTS SSS100505 J093417-174421 is an eclipsing novalike cataclysmic variable of the VY~Scl subtype, with an orbital period of 0.16329188(8) d. An analysis of the light curves with eclipse mapping techniques and an entropy landscape procedure indicates an orbital inclination of 81.5 degrees and a mass ratio of 0.45. Eclipse maps reveal two diametrically opposed asymmetric arcs of enhanced emission in the intermediate and outer regions of an accretion disk elongated in the direction perpendicular to the line joining both stars, interpreted as tidally-induced spiral shock arms. The accretion disk is 50 per cent larger in the longer wavelength TESS data than in the optical range, in line with the expected radial temperature gradient of an opaque steady-state disk. The combination of a small optical disk radius (of 21 per cent of the orbital separation) and high orbital inclination explains the relatively faint absolute magnitude of $M_g = 7.44$ for a novalike variable.