AAVSO: American Association of Variable Star Observers

Observations and Analysis of a Detached Eclipsing Binary, V385 Camelopardalis

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, Physics and Astronomy Department, Appalachian State University, 525 Rivers Street, Boone, NC 28608-2106; catondb@appstate.edu
Danny R. Faulkner
Johnson Observatory, 1414 Bur Oak Court, Hebron, KY 41048; dfaulkner@answersingenesis.org


V385 Cam is found to be a G7 ± 2 type (T ~ 5500 K) pre-contact eclipsing binary. It was observed on December 15, 16, 17, and 18, 2017, at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University. Three times of minimum light were determined from our present observations, which include two primary eclipses and one secondary eclipse. Twelve other minima were determined or found in the literature. This allowed an 18.5-year period study and a possible quadratic ephemeris was found. The resulting weak period decrease may indicate that the solar type binary is undergoing magnetic braking. A BVRcIc simultaneous Wilson-Devinney Program (wd) solution gives a detached solution. This model has a primary component with a 96% fill-out and a secondary component with 91% fill-out. The solution has a mass ratio of 0.390 ± 0.001, and a component temperature difference of ~ 1000 K. The large ΔT in the components verifies that the binary is not yet in contact. Two hot spots were used in the modeling, a polar spot and a smaller southern spot with a 120° colatitude. The binary star inclination is ~ 84.1 ± 0.2°, resulting in a total eclipse (secondary component) of 27.2 minutes in duration.