AAVSO: American Association of Variable Star Observers

BVRcIc Study of the Short Period Solar Type, Near Contact Binary, NSVS 10083189

Volume 45 number 2 (2017)

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Ronald G. Samec
Natural Sciences Dept. Emmanuel College,181 Springs St., Franklin Springs, GA 30639; ronaldsamec@gmail.com
Amber Olsen
Natural Sciences Dept. Emmanuel College,181 Springs St., Franklin Springs, GA 30639
Daniel B. Caton
Dark Sky Observatory, Physics and Astronomy Department, Appalachian State University, 525 Rivers St., Boone, NC, 28608-2106
Danny R. Faulkner
Johnson Observatory, 1414 Bur Oak Ct., Hebron, KY 41048
Robert L. Hill
Department of Chemistry and Physics, Bob Jones University, 1700 Wade Hampton Blvd., Greenville, SC 29614


The first precision BVRcIc light curves of NSVS 10083189 were taken on eight nights in 2015 at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University and on one night on the SARA 1-m reflector at Kitt Peak National Observatory in remote mode. It is an ~ F8V eclipsing binary with a short period of 0.4542238 (2) d. Seven times of minimum light were calculated. In addition, seven observations at minima were determined from archived NSVS Data. A statistically significant negative quadratic ephemeris was calculated. A light curve analysis with the Wilson-Devinney program led to a semidetached-near contact configuration (larger component filling its critical lobe and the secondary just under filing). This may indicate that NSVS 10083189 is near the end of its Detached to Contact Binary Channel. Our synthetic light curve solution gave a mass ratio of 0.58, with component temperatures of 6250 and 4573 K. A 15° radius cool spot with a T-factor of 0.85 was determined on the primary star. Thus, magnetic braking may be its main process acting in the orbital evolution. The fill-out of the secondary star has apparently reached ~ 99%.