A Pulsational Distance to ω Centauri Based on Near‐Infrared Period‐Luminosity Relations of RR Lyrae Stars
| Autor: | M. Del Principe, P. B. Stetson, Massimo Dall'Ora, R. Buonanno, I. Ferraro, Jesper Storm, Mario Nonino, M. Monelli, Annalisa Calamida, G. Iannicola, L. M. Freyhammer, A. M. Piersimoni, Giuseppe Bono, C. E. Corsi, V. Ripepi, L. Pulone, Marco Castellani, Filippina Caputo |
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| Rok vydání: | 2006 |
| Předmět: |
FOS: Physical sciences
Photometric system Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Globular clusters: individual (ω Centauri) RR Lyrae variable Luminosity Settore FIS/05 - Astronomia e Astrofisica Stars: oscillations Astrophysics::Solar and Stellar Astrophysics Omega Centauri Astrophysics::Galaxy Astrophysics Physics Distance scale Astrophysics (astro-ph) Astronomy and Astrophysics Horizontal branch Stars: evolution Distance modulus Stars Stars: variables: other Space and Planetary Science Stars: horizontal-branch Globular cluster Astrophysics::Earth and Planetary Astrophysics |
| Zdroj: | The Astrophysical Journal. 652:362-369 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1086/508136 |
| Popis: | We present new Near-Infrared (J,K) magnitudes for 114 RR Lyrae stars in the globular cluster Omega Cen (NGC 5139) which we combine with data from the literature to construct a sample of 180 RR Lyrae stars with J and K mean magnitudes on a common photometric system. This is presently the largest such sample in any stellar system. We also present updated predictions for J,K-band Period-Luminosity relations for both fundamental and first-overtone RR Lyrae stars, based on synthetic horizontal branch models with metal abundance ranging from Z=0.0001 to Z=0.004. By adopting for the Omega Cen variables with measured metal abundances an alpha-element enhancement of a factor of 3 (about 0.5 dex) with respect to iron we find a true distance modulus of 13.70 (with a random error of 0.06 and a systematic error of 0.06), corresponding to a distance d=5.5 Kpc (with both random and systematic errors equal to 0.03 Kpc). Our estimate is in excellent agreement with the distance inferred for the eclipsing binary OGLEGC-17, but differ significantly from the recent distance estimates based on cluster dynamics and on high amplitude Delta Scuti stars. Comment: 24 pages, 7 figures, accepted for publication on The Astrophysical Journal |
| Databáze: | OpenAIRE |
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