Related papers: RR Lyrae From Binary Evolution: Abundant, Young an…

We present observations of RR Lyrae variables in the Local Group late-type spiral galaxy M33. Using the Advanced Camera for Surveys on the Hubble Space Telescope, we have identified 64 ab-type RR Lyraes in M33. We have estimated reddenings…

Although roughly half of all stars are considered to be part of binary or multiple systems, there are only two confirmed cases of RR Lyrae pulsators with companions. One of them is TU Uma (Wade et al 1999) - a classical RR Lyrae star in a…

Globular clusters are both primary fossils of galactic evolution and formation and are ideal laboratories for constraining the evolution of low-mass and metal-poor stars. RR Lyrae and type II Cepheid variables are low-mass, radially…

Red giants are increasingly used as stellar population tracers due to their well-understood evolution and the availability of asteroseismic observables. However, stellar binarity can alter observable properties and introduce strong biases.…

This paper presents an extensive overview of known and proposed RR Lyrae stars in binaries. The aim is to revise and extend the list with new Galactic field systems. We utilized maxima timings for eleven RRab type stars with suspicious…

Stellar mergers and accretion events have been crucial in shaping the evolution of the Milky Way (MW). These events have been dynamically identified and chemically characterised using red giants and main-sequence stars. RR Lyrae (RRL)…

We present new nonlinear, time-dependent convective hydrodynamical models of RR Lyrae stars computed assuming a constant helium-to-metal enrichment ratio and a broad range in metal abundances (Z=0.0001--0.02). The stellar masses and…

Double-mode RR Lyr type stars are important for studies of properties of horizontal-branch stars. In particular, two periods coupled with spectral properties give a mass estimate that is independent of evolutionary models. Here, we present…

Young {\alpha}-rich (YAR) stars within the old Galactic thick disk exhibit a dual characteristic of relative youth determined with asteroseismology and abundance enhancement in {\alpha} elements measured from high-resolution spectroscopy.…

Certain carbon-enhanced metal-poor stars likely obtained their composition via pollution from some of the earliest generations of asymptotic giant branch stars and as such provide important clues to early Universe nucleosynthesis. Recently,…

(Abridged) We carried out a period analysis on ~3700 RR Lyrae stars spread over ~50 square degrees towards the Sagittarius dwarf galaxy (Sgr). The RR Lyraes are distributed almost evenly between Sgr and the Milky Way. For Sgr members, the…

We identified and characterized the largest (536) RR Lyrae (RRL) sample in a Milky Way dSph satellite (Sculptor) based on optical photometry data collected over $\sim$24 years. The RRLs display a spread in V-magnitude ($\sim$0.35 mag) which…

Using evolutionary population synthesis we present integrated colours, integrated spectral energy distributions and absorption-line indices defined by the Lick Observatory image dissector scanner (referred to as Lick/IDS) system, for an…

We present new spectroscopic metal abundances for 74 RR Lyrae stars in omega Cen obtained with FLAMES. The well-known metallicity spread is visible among the RR Lyrae variables. The metal-intermediate (MInt) RR Lyrae stars ([Fe/H] ~ -1.2)…

RR Lyrae stars in the Milky Way are good tracers to study the kinematic behaviour and spatial distribution of older stellar populations. A recently established well documented sample of 217 RR Lyr stars with V<12.5 mag, has been used to…

We determine the fundamental stellar parameters of altogether 20 double-mode RR Lyrae (RRd) stars from the Galactic Field and the Large Magellanic Cloud, following our approach employed on the field RRd star BS Comae. The stars were…

High redshift galaxies permit the study of the formation and evolution of X-ray binary populations on cosmological timescales, probing a wide range of metallicities and star-formation rates. In this paper, we present results from a large…

The eleventh part of the OGLE-III Catalog of Variable Stars (OIII-CVS) contains 16836 RR Lyr stars detected in the OGLE fields toward the Galactic bulge. The total sample is composed of 11756 RR Lyr stars pulsating in the fundamental mode…

Despite their importance, very few RR Lyrae (RRL) stars have been known to reside in binary systems. We report on a search for binary RRL in the OGLE-III Galactic bulge data. Our approach consists in the search for evidence of the…

We have combined optical and near-infrared data of known RR Lyrae (RRL) stars in the bulge in order to study the spatial distribution of its metal-poor component by measuring precise reddening values and distances of 7663 fundamental-mode…