Cyclic variations in the periods of RR Lyr stars

TL;DR

This paper investigates cyclic period variations in RR Lyr stars, focusing on the Blazhko effect and light-time effects, using photometric and spectroscopic data to identify underlying causes and potential binary systems.

Contribution

It provides new observational evidence and analysis of cyclic period variations in RR Lyr stars, including spectroscopic confirmation of light-time effects and ongoing binary candidate searches.

Findings

Detection of amplitude variations linked to the Blazhko effect.

Spectroscopic evidence supporting light-time effects in KIC 2831097.

Initiation of binary candidate searches among RR Lyr stars.

Abstract

We report here on two types of cyclic variations that can be observed in the periods of RR Lyr stars, i.e., the Blazhko and the light-time effects. The former has been investigated by studying the amplitude variations recorded in RR Lyr itself, firstly by Kepler and then by the network of the "Very Tiny Telescopes" (VTTs). The latter on the basis of the new spectroscopic observations of the most promising candidate, KIC 2831097. The start of the search for binary candidates in the RR Lyr stars observed with the TAROT telescopes is also announced.