A new search for variable stars in the globular cluster NGC 63661

A. Arellano Ferro, Sunetra Giridhar, V. Rojas López, R. Figuera, D. M. Bramich, Patricia Rosenzweig

Research output: Contribution to journalArticle

16 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)365-380
Number of pages16
JournalRevista Mexicana de Astronomia y Astrofisica
Issue number2
Publication statusPublished - 1 Oct 2008
Externally publishedYes



  • Globular clusters: general
  • Globular clusters: individual (NGC 6366)
  • Stars: variables: other
  • Stars: variables: RR Lyrae

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Arellano Ferro, A., Giridhar, S., Rojas López, V., Figuera, R., Bramich, D. M., & Rosenzweig, P. (2008). A new search for variable stars in the globular cluster NGC 63661. Revista Mexicana de Astronomia y Astrofisica, 44(2), 365-380.