CCD photometry of the RR Lyrae stars in NGC 4147

Armando Arellano Ferro, Ma Jesús Arévalo, Carlos Lázaro, Manuel Rey, Daniel M. Bramich, Sunetra Giridhar

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21 Citations (Scopus)

Abstract

We report the results of CCD V and R photometry of the RR Lyrae stars known in NGC 4147. The periodicities of most variables are revised and new ephemerides are calculated. The Blazhko effect has been detected in V2 and V6. Three previously reported variables; V5, V9, and V15 are found to be non-variable. A new variable V18 was discovered with a period of 0.49205 days and an amplitude of 0.15 mag. Using the approach of Fourier decomposition of the light curves, the physical parameters of the RRab and RRc variables were estimated. The cluster is of the Oosterhoff type I. With the newly values [Fe/H]=-1.22±0.31 and 16.8±1.3 kpc, the cluster fits very well into the Oosterhoff type-metallicity and metallicity-temperature sequence found in globular clusters. A comparison with ZAHB models indicates that the RRab stars have not yet evolved off the horizontal branch, a result consistent with the mean period of the RRab variables and with the metallicity of the cluster derived in this work.

Original languageEnglish
Pages (from-to)209-221
Number of pages13
JournalRevista Mexicana de Astronomia y Astrofisica
Volume40
Issue number2
Publication statusPublished - 1 Oct 2004

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Keywords

  • Globular Clusters: NGC 4147
  • Stars: Variables: RR Lyrae

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Ferro, A. A., Arévalo, M. J., Lázaro, C., Rey, M., Bramich, D. M., & Giridhar, S. (2004). CCD photometry of the RR Lyrae stars in NGC 4147. Revista Mexicana de Astronomia y Astrofisica, 40(2), 209-221.