The First Light Curve Solutions and Period Changes of EW Psc and HN Psc

TL;DR

This paper presents the first light curve solutions and period change analysis for the binary stars EW Psc and HN Psc, revealing their contact configurations and stellar parameters using photometry and MCMC methods.

Contribution

It provides the first detailed light curve solutions and ephemeris for EW Psc and HN Psc, including analysis of period changes with a novel MCMC approach.

Findings

EW Psc is a near contact eclipsing binary with q=0.587.

HN Psc is a weak-contact W UMa binary with q=0.853.

Both systems show period variations and require cold spots to explain light curve asymmetries.

Abstract

The first light curve solutions of the stars EW and HN in Pisces constellation are presented. Photometry, and its' periodic changes are calculated and discussed. The analysis of O-C diagram done by MCMC approach in OCFit code and the new ephemeris provided for two binary systems. The light curve solutions obtained. The results show that EW Psc is a near contact eclipsing binary system with a photometric mass ratio q = 0.587, and the fillout factor -0.034 and -0.018 for primary and secondary components, respectively. The solution results also show that the system HN Psc is a weak-contact W UMa eclipsing binary with a photometric mass ratio q = 0.853, and with fillout factor 5.6%. The light curves solutions required the cold spot accounting for the O'Connell effect.