Optical characterization and radial velocity monitoring with Belgian and Indian telescopes (ORBIT): the eclipsing binaries EPIC 211982753 and EPIC 211915147

Abstract

The K2 eclipsing binary (EB) candidates EPIC 211982753 (hereinafter called EPIC2753) and EPIC 211915147 (hereinafter called EPIC5147) are characterized with the help of photometric and high-resolution spectroscopic data. The light curve analysis uses the Rc-band photometric data from the 1.3-m Devasthal Fast Optical Telescope (DFOT, India), ASAS-3, and K2 observations. High-resolution echelle ´ spectra are collected using the HERMES spectrograph at the 1.2-m MERCATOR telescope (La Palma, Spain). The synthetic light and radial velocity curves are generated with the help of the modeling package PHOEBE 1.0. The orbital period analysis based on the ∼3.2 yr of K2 observations does not show any change in the orbital period of both targets. The component masses M1, 2 are estimated as 1.69(0.02) and 1.59(0.02) M for EPIC2753, and 1.48(0.01) and 1.27(0.01) M for EPIC5147. Both systems are high mass-ratio EBs with q>0.85. The component radii R1, 2 are found to be 1.66(0.02) and 1.53(0.02) R for EPIC2753, and 1.80(0.05) and 1.42(0.05) R for EPIC5147. The distances of EPIC2753 and EPIC5147 are determined as 238(4) and 199(5) pc, respectively. MESA Isochrones and Stellar Tracks are used to understand the evolutionary status of both systems.