New Observations of V530 Andromedae: a Critical Contact Binary?

Volume 44 number 2 (2016)

Ronald G. Samec: Astronomy Group, Department of Natural Sciences., Emmanuel College, 181 Springs St., Franklin Springs, GA 30639, ronaldsamec@gmail.com
Heather Chamberlain: American Public University System, 111 W. Congress St., Charles Town, WV 25414, 4hcham@gmail.com
Daniel B. Caton: Dark Sky Observatory, Physics and Astronomy Department, Appalachian State University, 525 Rivers St., Boone, NC, 28608-2106, dbcaton@apstate.edu
Danny R. Faulkner: Johnson Observatory, 1414 Bur Oak Ct., Hebron, KY 41048, DRFAULKN@mailbox.sc.edu
Jeremy D. Clark: Bob Jones University, 1700 Wade Hampton Blvd., Greenville, SC 29614, jclar904@students.bju.edu
Travis Shebs: University of South Carolina, Department of Physics and Astronomy, Jones PSC Room 404, Columbia, SC 29208, shebs@email.sc.edu

Abstract

We follow up on single coverage UBVRcIc light curves taken in 2011 and analyses. Our present BVRcIc light curves with ample coverage were taken October and November 2013 and January 2014 with the Dark Sky Observatory 0.81-meter reflector of Appalachian State University. They reveal the early-type V530 And as a totally eclipsing shallow or critical contact solar-type binary rather than semidetached near-contact one. In our extended period study, over a 14.25-year interval, we find a continuously decreasing period. This fits the scenario of magnetic braking for solar-type binaries. The temperatures of the primary and secondary components are estimated at 6750 and 6030 K. The component temperature difference is large for a contact binary. The fill-out, however, is a mere 5% so it is near critical contact. The mass ratio, M2 / M1, was found to be 0.386. Two star spots, probably magnetic in origin, were determined. We suspect that the binary has recently achieved physical contact for the first time.