Abstract We present new photometry for two contact binaries, Y Sex and V1363 Ori, which were observed by three small telescopes in China. By using the W-D method, the absolute parameters are updated from new BVR light curves and previous radial velocity curves. Results identify that two binaries are deep, lowmass ratio (DLMR) overcontact binaries with q ≤ 0.25 and f ≥ 50%. From the temperature-luminosity diagram, the primary components are slightly evolved main-sequence stars, whose evolutionary ages are ∼ 2.51 Gyr for Y Sex and ∼ 3.56 Gyr for V 1363 Ori, respectively. From the (O − C) curves, it is found that the orbital periods may be undergoing secular increase with cyclic variations, which may be interpreted either by magnetic activity cycles or by the light-time orbit effect. With period increasing, this kind of DLMR overcontact binaries, such as Y Sex and V1363 Ori, will evolve into the rapid-rotating single stars.
Keywords : binaries (including multiple): close — binaries: eclipsing — stars: fundamental parameters — stars: individual (Y Sex, V1363 Ori)
It accepts original submissions from all over the world and is internationally published and distributed by IOP