Evidence for an overluminosity of the variable star RR Lyrae, and a revised distance to the LMC

Catelan, M.; Cortes C.

Abstract

We use theoretical models to establish a tight relationship for the absolute magnitudes of RR Lyrae stars as a function of their periods and Strömgren pseudocolor co = (u - v)o - (v - b) o. Applying this to RR Lyr, and comparing the result with the predicted average absolute magnitude for stars of similar metallicity from the same models, yields an overluminosity of 0.064 ± 0.013 mag in Strömgren y (and thus similarly in V) for RR Lyr. Based on a revised value for RR Lyr's trigonometric parallax, and on a newly derived reddening value of E(B - V) = 0.015 ± 0.020, we provide a corrected relationship between average absolute magnitude and metallicity for RR Lyrae stars that takes RR Lyr's evolutionary status fully into account for the first time. Applying this relationship to the LMC, we derive a revised true distance modulus of (m - M)o = 18.44 ± 0.11. © 2008. The American Astronomical Society. All rights reserved.

Más información

Título según WOS: Evidence for an overluminosity of the variable star RR Lyrae, and a revised distance to the LMC
Título según SCOPUS: Evidence for an overluminosity of the variable star RR Lyrae, and a revised distance to the LMC
Título de la Revista: ASTROPHYSICAL JOURNAL LETTERS
Volumen: 676
Número: 2
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2008
Página de inicio: L135
Página final: L138
Idioma: English
URL: http://stacks.iop.org/1538-4357/676/i=2/a=L135
DOI:

10.1086/587515

Notas: ISI, SCOPUS