Finest light curve details, physical parameters, and period fluctuations of CoRoT RR Lyrae stars

TL;DR

This study analyzed CoRoT RR Lyrae stars, discovering new stars and Blazhko effects, examining period fluctuations, and estimating physical parameters, thereby enriching the understanding of these variable stars using space-based data.

Contribution

The paper fills the gap in CoRoT RR Lyrae star data by identifying nine new stars, including three with Blazhko effects, and provides detailed analysis of their physical and pulsation properties.

Findings

Seven new RR Lyrae stars discovered.

Three new Blazhko stars identified.

Significant period fluctuations observed in one star.

Abstract

The CoRoT satellite supplied the scientific community with a huge data base of variable stars. Among them the RR Lyrae stars have intensively been discussed in numerous papers in the last few years, but the latest runs have not been checked to find RR Lyrae stars up to now. Our main goal was to fill this gap and complete the CoRoT RR Lyrae sample. We found nine unstudied RR Lyrae stars. Seven of them are new discoveries. We identified three new Blazhko stars. The Blazhko effect shows non-strictly repetitive nature for all stars. The frequency spectrum of the Blazhko star CoRoT 104948132 contains second overtone frequency with the highest known period ratio. The harmonic amplitude and phase declines with the harmonic order were studied for non-Blazhko stars. We found a period dependent but similar shape amplitude decline for all stars. We discovered significant random period fluctuation for one of the two oversampled target, CM Ori. After a successful transformation of the CoRoT band parameters to the Johnson V values we estimated the basic physical properties such as mass, luminosity, metallicity. The sample can be divided into two subgroups with respect to the metallicity but otherwise the physical parameters are in the canonical range of RR Lyrae stars.