Variable stars in the globular cluster NGC 288

[Fe/H] and distance

A. Arellano Ferro, D. M. Bramich, S. Giridhar, R. Figuera Jaimes, N. Kains, K. Kuppuswamy

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

A search for variable stars in the globular cluster NGC 288 was carried out using a time-series of CCD images in the V and I filters. The photometry of all stellar sources in the field of view of our images, down to V ≈ 19 mag, was performed using difference image analysis (DIA). For stars of ≈ 15 mag, measurement accuracies of ≈ 8 mmag and ≈ 10 mmag were achieved for V and I respectively. Three independent search strategies were applied to the 5525 light curves but no new variables were found above the threshold limits characteristic of our data set. The use of older data from the literature combined with the present data allowed the refinement of the periods of all known variables. Fourier light curve decomposition was performed for the RRab and the RRc stars to obtain an estimate of [Fe/H]ZW = -1.62±0.02 (statistical) ±0.14 (systematic). A true distance modulus of 14.768±0.003 mag (statistical) ±0.042 mag (systematic), or a distance of 8.99±0.01 kpc (statistical) ±0.17 kpc (systematic) was calculated from the RRab star. The RRc star predicts a discrepant distance about one kiloparsec shorter but it is possibly a Blazhko variable. An independent distance from the P-L relationship for SX Phe stars leads to a distance of 8.9±0.3 kpc. The SX Phe stars V5 and V9 are found to be double mode pulsators.

Original languageEnglish
Pages (from-to)429-451
Number of pages23
JournalActa Astronomica
Volume63
Issue number4
Publication statusPublished - 1 Dec 2013

Fingerprint

variable stars
globular clusters
stars
field of view
image analysis
time series
decomposition
filter
light curve
photometry
charge coupled devices
filters
thresholds
estimates

Keywords

  • Globular clusters: individual: NGC 288
  • Stars: variables: delta Scuti
  • Stars: variables: RR Lyrae

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Arellano Ferro, A., Bramich, D. M., Giridhar, S., Figuera Jaimes, R., Kains, N., & Kuppuswamy, K. (2013). Variable stars in the globular cluster NGC 288: [Fe/H] and distance. Acta Astronomica, 63(4), 429-451.

Variable stars in the globular cluster NGC 288 : [Fe/H] and distance. / Arellano Ferro, A.; Bramich, D. M.; Giridhar, S.; Figuera Jaimes, R.; Kains, N.; Kuppuswamy, K.

In: Acta Astronomica, Vol. 63, No. 4, 01.12.2013, p. 429-451.

Research output: Contribution to journalArticle

Arellano Ferro, A, Bramich, DM, Giridhar, S, Figuera Jaimes, R, Kains, N & Kuppuswamy, K 2013, 'Variable stars in the globular cluster NGC 288: [Fe/H] and distance', Acta Astronomica, vol. 63, no. 4, pp. 429-451.
Arellano Ferro A, Bramich DM, Giridhar S, Figuera Jaimes R, Kains N, Kuppuswamy K. Variable stars in the globular cluster NGC 288: [Fe/H] and distance. Acta Astronomica. 2013 Dec 1;63(4):429-451.
Arellano Ferro, A. ; Bramich, D. M. ; Giridhar, S. ; Figuera Jaimes, R. ; Kains, N. ; Kuppuswamy, K. / Variable stars in the globular cluster NGC 288 : [Fe/H] and distance. In: Acta Astronomica. 2013 ; Vol. 63, No. 4. pp. 429-451.
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