TYC 1031 1262 1: An Anomalous Cepheid in a double-lined eclipsing binary

TL;DR

This study presents detailed analysis of TYC 1031 1262 1, an anomalous Cepheid in a binary system, revealing its physical properties, orbital dynamics, and evolutionary status, with implications for stellar evolution and population classification.

Contribution

First detailed characterization of an anomalous Cepheid in a double-lined eclipsing binary, including mass, radius, and orbital parameters, highlighting its evolutionary state.

Findings

The Cepheid has a pulsation period of 4.15270 days with a secular increase.

The system consists of two evolved stars with masses 1.64 and 0.93 solar masses.

The star is likely part of the thick-disk population in our galaxy.

Abstract

Multi-color light curves and radial velocities for TYC\,1031\,1262\,1 have been obtained and analyzed. TYC\,1031\,1262\,1 includes a Cepheid with a period of 4.15270$\pm$0.00061 days. The orbital period of the system is about 51.2857$\pm$0.0174 days. The pulsation period indicates a secular period increase with an amount of 2.46$\pm$0.54 min/yr. The observed B, V, and R magnitudes were cleaned for the intrinsic variations of the primary star. The remaining light curves, consisting of eclipses and proximity effects, are obtained and analyzed for orbital parameters. The system consists of two evolved stars, F8II+G6II, with masses of M$_1$=1.640$\pm$0.151 {\Msun} and M$_2$=0.934$\pm$0.109 {\Msun} and radii of R$_1$=26.9$\pm$0.9 {\Rsun} and R$_2$=15.0$\pm$0.7 {\Rsun}. The pulsating star is almost filling its corresponding Roche lobe which indicates the possibility of mass loss or transfer having taken place. We find an average distance of d=5070$\pm$250\,pc using the BVR and JHK magnitudes and also the V-band extinction. Kinematic properties and the distance to the galactic plane with an amount of 970 pc indicate that it belongs to the thick-disk population. Most of the observed and calculated parameters of the TYC\,1031\,1262\,1 lead to a classification of an Anomalous Cepheid.