RMxAA

Revista Mexicana de Astronomía y Astrofísica

ISSN: 3061-8649
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Keywords

globular clusters: general
globular clusters: individual (NGC 6366)
stars: variables: other
stars: variables: RR Lyrae
Astrophysics

How to Cite

A new search for variable stars in the globular cluster NGC 6366. (2008). Revista Mexicana De Astronomía Y Astrofísica, 44(2), 365-380. https://astronomia.unam.mx/journals/rmxaa/article/view/2008rmxaa..44..365a

Abstract

New CCD photometry of NGC 6366 has lead to the discovery of some variable stars. Two possible Anomalous Cepheids (or Pop II Cepheids), three long period variables, one SX Phe and one eclipsing binary have been found. Also, a list of 10 candidate variables is reported. The light curve of the RRab star, V1, has been decomposed into its Fourier harmonics, and the Fourier parameters were used to estimate the star's metallicity and distance; [Fe/H] = -0.87+/-0.14 and d = 3.2+/-0.1 kpc. It is argued that V1 may not be a member of the cluster but rather a more distant object. If this is so, an upper limit for the distance to the cluster of 2.8+/-0.1 kpc can be estimated. The P - L relationship for SX Phe stars and the identified modes in the newly discovered SX Phe variable, V6, allow yet another independent determination of the distance to the cluster, d = 2.7+/-0.1 kpc. The MV-[Fe/H] relationship for RR Lyrae stars is addressed and the case of V1 is discussed.
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