A Vindication of The RR Lyrae Fourier Light Curve Decomposition for the Calculation of Metallicity and Distance in Globular Clusters
We report the mean metallicity and absolute magnitude of RR Lyrae stars in a sample of 37 globular clusters, calculated via the Fourier decomposition of their light curves and ad hoc semi-empirical calibrations, in an unprecedented homogeneous approach. This enabled a new discussion of the metallici...
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Redalyc-UNAM |
| OAI Identifier: | oai:redalyc.org:57175502008 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=57175502008 https://www.redalyc.org/journal/571/57175502008/ https://www.redalyc.org/journal/571/57175502008/html/ https://www.redalyc.org/journal/571/57175502008/57175502008.epub https://www.redalyc.org/journal/571/57175502008/movil |
| Access Level: | acceso abierto |
| Palabra clave: | Física, Astronomía y Matemáticas stars: distances stars: horizontal branch Globular clusters: general stars: variables: RR Lyrae stars: fundamental parameters |
| Sumario: | We report the mean metallicity and absolute magnitude of RR Lyrae stars in a sample of 37 globular clusters, calculated via the Fourier decomposition of their light curves and ad hoc semi-empirical calibrations, in an unprecedented homogeneous approach. This enabled a new discussion of the metallicity dependence of the horizontal branch (HB) luminosity, as a fundamental distance indicator. The calibration for the RRab and RRc stars should be treated separately. For the RRab the dispersion is larger and non-linear. For the RRc stars the correlation is less steep, very tight and linear. The relevance of the HB structural parameter £, is highlighted and we offer a non-linear calibration of the form MV (Fe/H, £). Excellent agreement is found between values of Fe/H and MV from the light curve decomposition with spectroscopic values and distances obtained via Gaia-DR3 and HST. The variables census in 35 clusters includes 326 stars found by our program. |
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