UBVRI Observations, Analysis and Spectra of the Mature W UMa Contact Binary, V444 And
Abstract
We present the first precision UBVRI light curves, synthetic light curve solution, a period study and spectra for the V444 Andromedae, an FO V contact W UMa binary. Observations were taken at Lowell Observatory with the 0.81-m reflector from 28 through 30 September 2012 and the spectra at Dominion Astrophysical Observatory’s (DAO) with the 1.8m telescope on 22 July 2013 at a resolution of 60 Å/mm. We determined three times of minimum light from these observations, JD Hel Min I = 2456199.0239±0.0011, 2456199.9616± 0.0015 and JD Hel Min II = 2456198.7907±0.0005. From our period study we determined an improved linear ephemeris, J.D. Hel Min I = 2456199.9618±0.0003d + 0.46877942±0.00000005×E The period has been stable over the past 9.6 years 7500 orbits). After an extensive mass ratio-search, the lowest residual mass ratio was found to be 0.48. Our final Wilson-Devinney Program computation determined that the system is an A-type W U Ma contact binary with a fill-out of nearly 51%. Despite its temperature (7200-7300 K), two magnetic spots were found on the primary component, a 10 degree radius equatorial dark spot, T-factor=0.88 and a 23 degree radius near polar hot spot, T-factor=1.10. The component temperature difference is only ~80K. These parameters tell us that the V444 And is a mature solar type binary.
- Publication:
-
American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22315551S