V455 Car: an oscillating eclipsing Algol-type binary in triple star system

TL;DR

This paper presents a detailed study of the eclipsing binary V455 Car, revealing a third body, a semi-detached configuration, and the primary star's potential SPB/SLF variability, contributing new insights into complex binary star systems.

Contribution

It provides the first photometric solutions from TESS data, identifies a third body through $O-C$ analysis, and suggests the primary star may be an SPB/SLF star, highlighting complex dynamics in this system.

Findings

Detection of a third body with minimal mass 0.59 M_sun

Identification of the primary as a potential SPB/SLF star

Observation of a 26.62-year periodic variation in orbital period

Abstract

V455 Car is a southern oscillating eclipsing Algol-type system with an orbital period of 5.132888 days. Our first photometric solutions based on the Transiting Exoplanet Survey Satellite indicate that it is a semi-detached binary with the secondary star is almost filling its Roche lobe. The noticeable O'Connell effect in light curve could be explained by hot spot on the primary component, which may be attributed to the mass transfer from the secondary component to the primary one. The absolute parameters are determined as: $M_{1} = 5.30 \pm 1.10 \, \rm M_{\odot}$, $R_{1} = 3.17 \pm 0.22 \, \rm R_{\odot}$ for the primary, and $M_{2} = 1.58 \pm 0.32 \, \rm M_{\odot}$, $R_{2} = 6.66 \pm 0.46 \, \rm R_{\odot}$ for the secondary. \textbf{Based on $O-C$ analysis, we find a periodic variation of $P_3=26.62(\pm1.66)\,yr$. The periodic oscillation suggests a possible third body with a minimal mass of $0.59(\pm0.13)\,\rm M_{\odot}$}. It is speculated that the secondary star has undergone a longer evolution, leading to a mass ratio reversal being experienced in the binary system. Our frequency analysis finds that the primary of V455 Car may be an SPB/SLF star. This study reports a novel example of an oscillating eclipsing Algol-type system featuring an SPB/SLF primary star and a red giant star, which suggest that strong observational results for a high incidence of third bodies in massive binaries.