A Multicolour Photometric Study of the neglected eclipsing binary FT Ursae Majoris

TL;DR

This study presents multicolour photometric observations and analysis of the neglected eclipsing binary FT Ursae Majoris, revealing it as an evolved contact binary with nearly identical components and low light variation amplitude.

Contribution

It provides the first detailed multicolour light curve analysis of FT UMa using the Wilson-Devinney code, confirming its contact binary nature with specific physical parameters.

Findings

FT UMa is an evolved contact binary with 15.3% contact degree.

The low light variation amplitude is due to low inclination and similar component sizes.

The third component contributes about 10% of the light, but does not significantly dilute the light curve.

Abstract

The multicolour photometric observations of the neglected eclipsing binary FT Ursae Majoris (FT UMa) were obtained in 2010. The 2003 version of Wilson-Devinney code was used to analyze the light curves in $B$, $V$, and $R$ bands simultaneously. Based on the spectroscopic mass ratio $q=0.984$ published by Pribulla et al., it is found that FT UMa is an evolved contact binary with a contact degree of 15.3%. The low amplitude of light variations, $\sim 0.15$ mag, arises mainly from a moderately low inclination angle of $i=62.^{\circ}80$ and almost identical components in size rather than the light dilution of a third component, which contributes light of only $\sim 10%$