Solar-like oscillations in a metal-poor globular cluster with the hubble space telescope

Dennis Stello, Ronald Lynn Gilliland

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

We present analyses of variability in the red giant stars in the metal-poor globular cluster NGC 6397, based on data obtained with the Hubble Space Telescope. We use a nonstandard data reduction approach to turn a 23 day observing run originally aimed at imaging the white dwarf population, into time-series photometry of the cluster's highly saturated red giant stars. With this technique we obtain noise levels in the final power spectra down to 50 parts per million, which allows us to search for low-amplitude solar-like oscillations. We compare the observed excess power seen in the power spectra with estimates of the typical frequency range, frequency spacing, and amplitude from scaling the solar oscillations. We see evidence that the detected variability is consistent with solar-like oscillations in at least one and perhaps up to four stars. With metallicities 2 orders of magnitude lower than those of the Sun, these stars present so far the best evidence of solar-like oscillations in such a low-metallicity environment.

Original languageEnglish (US)
Pages (from-to)949-955
Number of pages7
JournalAstrophysical Journal
Volume700
Issue number2
DOIs
StatePublished - Jan 1 2009

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solar oscillations
globular clusters
Hubble Space Telescope
oscillation
red giant stars
metal
metals
metallicity
power spectra
stars
data reduction
photometry
sun
spacing
frequency ranges
time series
scaling
estimates

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Stello, Dennis ; Gilliland, Ronald Lynn. / Solar-like oscillations in a metal-poor globular cluster with the hubble space telescope. In: Astrophysical Journal. 2009 ; Vol. 700, No. 2. pp. 949-955.
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Solar-like oscillations in a metal-poor globular cluster with the hubble space telescope. / Stello, Dennis; Gilliland, Ronald Lynn.

In: Astrophysical Journal, Vol. 700, No. 2, 01.01.2009, p. 949-955.

Research output: Contribution to journalArticle

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