AAVSO: American Association of Variable Star Observers

VRcIc Photometric Study of the Totally Eclipsing Pre-W UMa Binary, V616 Camelopardalis: Is it Detached?

Volume 47 number 2 (2019)

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Ronald G. Samec
Faculty Research Associate, Pisgah Astronomical Research Institute, 1 PARI Drive, Rosman, NC 28772; ronaldsamec@gmail.com
Daniel B. Caton
Dark Sky Observatory, Department of Physics and Astronomy, Appalachian State University, 525 Rivers Street, Boone, NC 28608-2106; catondb@appstate.edu
Davis R. Gentry
Dark Sky Observatory, Department of Physics and Astronomy, Appalachian State University, 525 Rivers Street, Boone, NC 28608-2106; gentrydr@appstate.edu
Danny R. Faulkner
Johnson Observatory, 1414 Bur Oak Court, Hebron, KY 41048

Abstract

V616 Cam is a F3V±3 type (T ~ 6750 ± 400 K) eclipsing binary. It was observed on March 5, 6, 9, and 30, 2017, at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University. Five times of minimum light were determined from our present observations, which include three primary eclipses and two secondary eclipses. In addition, two other timings were given, one in VSX, and one in Shaw’s list of near contact binaries. The following quadratic ephemeris was determined from the available times of minimum light: JD Hel Min I = 2457817.8367 ± 0.0016 d + (0.52835050 ± 0.00000108) × E – (0.00000000238 ± 0.000000000009) × E^2. The rapid period decrease may indicate that the binary is undergoing magnetic braking and is approaching its contact configuration. The possibility of a third body is discussed, but no third light was determined in the solution. VRcIc simultaneous Wilson-Devinney program solutions preferred a near semi-detached solution (the primary component near filling its critical lobe and the secondary slightly underfilling, ~ V1010 Oph type). Mode 2, 4, and 5 solutions were determined to arrive at this result. The noted solution gives slightly better sum of square residuals. This solution gives a mass ratio of ~ 0.36 and a component temperature difference of ~ 2090 K. A BinaryMaker-fitted dark spot altered slightly but was not eliminated in the wd synthetic light curve computations. A 16 ± 2° radius spot is on the larger component above the equator with a T-factor of 0.95. A total eclipse of 38 minutes occurs at phase 0.5.