Observations, Roche Lobe Analysis, and Period Study of the Eclipsing Contact Binary System GM Canum Venaticorum

Volume 46 number 1 (2018)

Download this article (pdf)

Kevin B. Alton

UnderOak Observatory, 70 Summit Avenue, Cedar Knolls, NJ; kbalton@optonline.net

Robert H. Nelson

Mountain Ash Observatory, 1349 Garvin Street, Prince George, BC V2M 3Z1, Canada Guest Investigator, Dominion Astrophysical Observatory Herzberg Institute of AstrophysicsNational Research Council of Canada

Abstract

GM CVn is an eclipsing W UMa binary system (P = 0.366984 d) which has been largely neglected since its variability was first detected during the ROTSE campaign (1999–2000). Other than a single unfiltered light curve (LC) no other photometric data have been published. LC data collected in three bandpasses (B, V, and Rc) at UnderOak Observatory (UO) produced three new times of minimum for GM CVn. These along with other eclipse timings from the literature were used to update the linear ephemeris. Roche modeling to produce synthetic LC fits to the observed data was accomplished using binary maker 3, wdwint56a, and phoebe v.31a. Newly acquired radial velocity data were pivotal to defining the absolute and geometric parameters for this partially eclipsing binary system. An unspotted solution achieved the best Roche model fits for the multi-color LCs collected in 2013.