Radial Velocity Studies of Close Binary Stars. XV

TL;DR

This paper presents radial velocity measurements and orbital analyses for eight close binary star systems, along with additional data on seven other systems, including complex and pulsating binaries, expanding the understanding of their orbital and spectral properties.

Contribution

It provides new radial velocity data, orbital solutions, and spectral type estimates for multiple close binary systems, including complex and pulsating stars, using consistent analysis methods.

Findings

Orbital parameters derived for eight binary systems.

Radial velocities measured for seven additional systems.

Evidence of non-radial pulsations in two stars.

Abstract

Radial-velocity measurements and sine-curve fits to the orbital radial velocity variations are presented for the last eight close binary systems analyzed the same way as in the previous papers of this series: QX And, DY Cet, MR Del, HI Dra, DD Mon, V868 Mon, ER Ori, and Y Sex. For another seven systems (TT Cet, AA Cet, CW Lyn, V563 Lyr, CW Sge, LV Vir and MW Vir) phase coverage is insufficient to provide reliable orbits but radial velocities of individual components were measured. Observations of a few complicated systems observed throughout the DDO close-binary program are also presented; among them an especially interesting is the multiple system V857 Her which - in addition to the contact binary - very probably contains one or more sub-dwarf components of much earlier spectral type. All suspected binaries which were found to be most probably pulsating stars are briefly discussed in terms of mean radial velocities and projected rotation velocities (v sin i) as well as spectral type estimates. In two of them, CU CVn and V752 Mon, the broadening functions show a clear presence of non-radial pulsations. The previously missing spectral types for the DDO I paper are given here in addition to such estimates for most of the program stars of this paper.