A theoretical scenario for Galactic RR Lyrae in the Gaia database: constraints on the parallax offset

Abstract

On the basis of an extended set of nonlinear convective RR Lyrae pulsation models we derive the first theoretical light curves in the Gaia bands and the corresponding intensity-weighted mean magnitudes and pulsation amplitudes. The effects of chemical com-position on the derived Bailey diagrams in the Gaia filters are discussed for both Fundamental and First Overtone mode pulsators. The inferred mean magnitudes and colors are used to derive the first theoretical Period-Wesenheit relations for RR Lyrae in the Gaia filters. The application of the theoretical Period-Wesenheit relations for both the Fundamental and FirstOvertone mode to Galactic RR Lyrae in the Gaia Data Release 2 database and complementary information on individual metal abundances, allows us to derive theoretical estimates of their individual parallaxes. These results are compared with the astrometric solutions to conclude that a very small offset, consistent with zero, is required in order to reconcile the predicted distances with Gaia results.

Accepted for publication on MNRAS

References in corpus (7)

• The Gaia mission
• Gaia Data Release 1: Catalogue validation
• YBC, a stellar bolometric corrections database with variable extinction coefficients: an application to PARSEC isochrones
• The RR Lyrae Period - K Luminosity relation for Globular Clusters: an observational approach
• Variable stars in the newly discovered Milky Way satellite in Bootes
• New near-infrared period-luminosity-metallicity relations for RR Lyrae stars and the outlook for Gaia
• On the RR Lyrae stars in globulars: IV. $\omega$ Centauri Optical UBVRI Photometry

Cited by in corpus (6)

• The updated BaSTI stellar evolution models and isochrones: II. alpha-enhanced calculations
• TESS observations of Cepheid stars: first light results
• RR Lyrae variables in Messier 53: Near-infrared Period--Luminosity relations and the calibration using Gaia Early Data Release 3
• New LZ and PW(Z) relations of RR Lyrae stars calibrated with Gaia EDR3 parallaxes
• Probing galactic double-mode RR Lyrae stars against Gaia EDR3
• Bright single-mode RR Lyrae stars: matching Gaia EDR3 with pulsation and evolutionary models