Parameter Solutions for the System AP Leonis
Abstract
The eclipsing binary system AP LEO is an overcontact binary of W UMa type with low surface temperature and a short period of 0.43 days and with a mass ratio well below unity. Monitoring lightcurves published in 1989 and 1993 displayed changes to this contact system uncommon in such a short period. New CCD photometric lightcurves in the V and R bands are presented. O-C values have been computed using thirteen new times of light minimums along with 62 minimums previously published in the literature. A sinusoidal trend is apparent and several authors have interpreted this small amplitude cyclic oscillation to a triple system containing a third component. This shallow sine curve is superposed on an increasing secular period. The most recent spectroscopic study classified the spectral type as F7-8 V. Photometric solutions of the lightcurve and computed parameters are compared with five other investigations of the binary system. The changes in the parameters in such a brief time indicate the orbital period variations are caused by mass transfer from the primary star to the secondary causing a decrease or change in angular momentum loss.
- Publication:
-
Society for Astronomical Sciences Annual Symposium
- Pub Date:
- May 2007
- Bibcode:
- 2007SASS...26...61S