Physical parameters of close binaries QX Andromedae, RW Comae Berenices, MR Delphini, and BD +07{\circ} 3142

TL;DR

This study derives physical parameters of four close binary star systems using combined photometric and spectroscopic data, revealing their classifications and surface activity features, including spots and overcontact configurations.

Contribution

First comprehensive analysis of the light curves for BD +07° 3142, establishing it as an overcontact W UMa type binary with polar spots.

Findings

BD +07° 3142 is an overcontact W UMa binary with polar spots.

QX And is an A subtype W UMa binary.

RW Com is a W subtype W UMa binary with a bright spot.

Abstract

Aims. We analyze new multicolor light curves and recently published radial velocity curves for close binaries QX And, RW Com, MR Del, and BD +07{\circ} 3142 to determine the physical parameters of the components. Methods. The light curves are analyzed using a binary star model based on Roche geometry to fit the photometric observations. Spectroscopic parameters, such as the mass ratios and spectral types, were taken from recent spectroscopic studies of the systems in question. Results. Our findings provide consistent and reliable sets of stellar parameters for the four studied binary systems. Of particular interest is the BD +07{\circ} 3142 system, since this is the first analysis of its light curves. We find that it is an overcontact binary of W UMa type and W subtype, and that each component has a large cool spot in the polar region. QX And is an A subtype, and RW Com a W subtype W UMa binary, and in both systems we find a bright spot in the neck region between the components. MR Del is a detached binary with a complex light curve that we could model with two cool spots on the hotter component.