Radial Velocity Studies of Close Binary Stars.XIII

TL;DR

This paper presents radial velocity measurements and orbital fits for ten close binary star systems, discovering two new triple systems and analyzing unique features like rapid period increase and low-mass ratios.

Contribution

It provides new radial velocity data, identifies two previously unknown triple systems, and discusses unusual characteristics of specific binaries such as V1191 Cyg.

Findings

Discovered two new triple systems: BD+7_3142 and PY Vir.

Identified a low-mass ratio binary V1191 Cyg with rapid period increase.

Most studied systems are contact binaries, with some exceptions.

Abstract

Radial-velocity measurements and sine-curve fits to the orbital radial velocity variations are presented for ten close binary systems: EG Cep,V1191 Cyg, V1003 Her, BD+7_3142, V357 Peg, V407 Peg, V1123 Tau, V1128 Tau, HH UMa, and PY Vir. While most of the studied eclipsing systems are contact binaries, EG Cep is a detached or a semi-detached double-lined binary and V1003 Her is a close binary of an uncertain type seen at a very low inclination angle. We discovered two previously unknown triple systems, BD+7_3142 and PY Vir, both with late spectral-type (K2V) binaries. Of interest is the low-mass ratio (q = 0.106) close binary V1191 Cyg showing an extremely fast period increase; the system has a very short period for its spectral type and shows a W-type light curve, a feature rather unexpected for such a low mass-ratio system.