The low mass ratio contact binary system V728 Herculis

TL;DR

This study investigates the orbital period changes and physical characteristics of the low mass ratio contact binary V728 Her, revealing mass transfer, possible tertiary influence, and evolutionary status.

Contribution

The paper provides detailed orbital and physical parameters of V728 Her, including evidence of period increase and potential tertiary effects, which are novel insights into this system.

Findings

Orbital period is increasing at a rate of 1.92x10^-7 days/year.

Mass transfer rate from the less to more massive component is 2.51x10^-8 solar masses per year.

V728 Her is a deep, low mass ratio contact binary with q=0.16.

Abstract

We present the orbital period study and the photometric analys of the contact binary system V728 Her. Our orbital period analysis shows that the period of the system increases (dP/dt=1.92x10^-7dyr^-1) and the mass transfer rate from the less massive component to more massive one is 2.51x10^-8M_suny^-1. In addition, an advanced sinusoidal variation in period can be attributed to the light-time effect by a tertiary component or the Applegate mechanism triggered by the secondary component. The simultaneous multicolor BVR light and radial velocity curves solution indicates that the physical parameters of the system are M1=1.8M_sun, M2=0.28M_sun, R1=1.87R_sun, R2=0.82R_sun, L1=5.9L_sun, and L2=1.2L_sun. We discuss the evolutionary status and conclude that V728 Her is a deep (f=81%), low mass ratio (q=0.16) contact binary system.