Photometric studies of five eclipsing binaries: RS Ser, V0449 Per, MR Del, V593 Cen, and V1095 Her

Abstract

ABSTRACT RS Ser, V449 Per, MR Del, V593 Cen, and V1095 Her are short-period eclipsing binaries. We made photometric observations on 38 nights using four 1-m-class telescopes and plotted eight light curves. We determined the spectral type of V449 Per as K0(±2)V using low-resolution spectra from the Lijiang 2.4-m telescope. We found cyclic variation in the orbital periods for RS Ser and V1095 Her, and confirmed the cyclic variation of MR Del. The periods of the hypothetical third bodies are close to the duration of observation, and the detected cycles are questionable. For V593 Cen, we followed the previously published suggestion that it probably has a black hole with a minimum mass of 3.68 M⊙. We used the orbital period decreasing at a rate of 8.2(0.1) × 10−8 d yr–1 to explain it. There are two alternative interpretations, and hence the black hole candidate of V593 Cen remains questionable because the minimum points are concentrated in four clusters. The period of V449 Per increases continuously at a rate of 9.5 × 10−8 d yr–1, which can be attributed to mass transfer from the less massive component to the more massive component. For MR Del, we used a new light curve and the published radial velocity to revise its absolute parameters. Furthermore, we revised the photometric solution of V593 Cen and confirmed it as an early-type contact binary with a higher contact factor. We obtained preliminary photometric parameters for RS Ser, V1095 Her, and V449 Per.