AAVSO: American Association of Variable Star Observers

New Photometric Observations and the First Wilson Program Analysis of the Totally Eclipsing, Solar Type Binary, UU Camelopardalis

Volume 50 number 2 (2022)

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Ronald G. Samec
Pisgah Astronomical Research Institute, 112 Idlewood Acres, Hartwell, GA 30643; ronaldsamec@gmail.com
Daniel Caton
Dark Sky Observatory, Department of Physics and Astronomy, Appalachian State University, 525 Rivers Street, Boone, NC 28608-2106; catondb@appstate.edu
Danny Faulkner
Johnson Observatory, 1414 Bur Oak Court, Hebron, KY 41048; dfaulkner@answersingenesis.org

Abstract

CCD BVRI light curves of UU Cam were taken on 19, 20, 21, 23, 24, and 27 January 2021 by Daniel Caton at the Dark Sky Observatory, North Carolina, with the 0.81-m reflector of Appalachian State University. The variability of UU Cam was discovered by Baker. UU Cam is an eclipsing binary with a totally eclipsing secondary. The eclipse duration is some 54 minutes. The period behavior is quadratic following JD 2454860. Before this, there appears to be a constant period or the scatter is very high. There are 34 timings in the period study covering an interval of ~29.6 years. From our study, the period is found to be increasing. This could be due to mass transfer making the mass ratio decrease. A Wilson-Devinney analysis reveals that the system is an A-type (most massive component is the hottest) W UMa binary with a fairly extreme mass ratio, q = 0.2551 ± 0.0002. Its Roche Lobe fill-out is an extreme ~60%. One cool spot was needed in the solution. The temperature difference of the components is only ~121 K. The inclination is high, 82.04 ± 0.05, resulting in a time of constant light in the primary eclipse.