Period Study and Analysis of 2017 BVRcIc Observations of the Totally Eclipsing, Solar Type Binary, MT Camelopardalis
Volume 46 number 2 (2018)
- 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
- Danny R. Faulkner
- Johnson Observatory, 1414 Bur Oak Court, Hebron, KY 41048
Abstract
We report here on a period study and analysis of 2017 BVRcIc light curves of MT Camelopardalis (GSC03737-01085). It is a solar type (T ~ 5500 K) eclipsing binary. It was observed for six nights in December 2017 at Dark Sky Observatory (DSO) with the 0.81-m reflector. Five times of minimum light were calculated from Terrell, Gross, and Cooney’s (2016, IBVS 6166) 2004 and 2016 observations (hereafter TGC). In addition, eleven more times were taken from the literature and six determined from the present observations. From these 15 years of observations a quadratic ephemeris was calculated: JD Hel Min I = 2458103.66121 d + 0.36613905 × E – 0.000000000035 × E2 (2) ±0.00051 ±0.00000021 ±0.000000000015 A BVRcIc filtered simultaneous Wilson-Devinney Program (WD) solution gives a mass ratio (0.3385 ± 0.0014), very nearly the same as TGC’s (0.347 ± 0.003), and a component temperature difference of only ~140 K. As with TGC, no spot was needed in the modeling. Our modeling (beginning with binary maker 3.0 fits) was done without prior knowledge of TGCs. This shows the agreement achieved when independent analyses are done with the Wilson code. The present observations were taken 1.8 years later than the last curves by TGC, so some variation is expected. The Roche Lobe fill-out of the binary is ~ 13% and the inclination is ~ 83.5 degrees. The system is a shallow contact W-type W UMa binary, albeit the amplitudes of the primary and secondary eclipse are very nearly identical. An eclipse duration of ~ 21 minutes was determined for the secondary eclipse and the light curve solution.