THE RØMER DELAY AND MASS RATIO OF THE sdB+dM BINARY 2M 1938+4603 FROM KEPLER ECLIPSE TIMINGS

摘要: The eclipsing binary system 2M 1938+4603 consists of a pulsating hot subdwarf B star and cool M dwarf companion in an effectively circular three-hour orbit. light curve shows both primary secondary eclipses, along with strong reflection effect from the companion. Here, we present constraints on component masses eccentricity derived Romer delay eclipse. Using six months publicly available Kepler photometry obtained short-cadence mode, fit model profiles to eclipses measure their centroid values. We find that eclipse arrives average 2.06 {+-} 0.12 s after midpoint between eclipses. Under assumption orbit, calculate this time mass ratio q = 0.2691 0.0018 individual M{sub sd} 0.372 0.024 Sun} c} 0.1002 0.0065 for sdB dwarf, respectively. These results differ slightly those previously published light-curve modeling solution; difference, however, may be reconciled very small eccentricity, ecos {omega} Almost-Equal-To 0.00004. also report decrease orbital period P-dot =more » (-1.23 0.07) Multiplication-Sign 10{sup -10}.« less