A blue straggler binary with three progenitors in the core of a globular cluster

  title={A blue straggler binary with three progenitors in the core of a globular cluster},
  author={C. Knigge and R. Gilliland and A. Dieball and D. Zurek and M. Shara and K. J. U. O. Southampton and Stsci and Amnh},
  journal={The Astrophysical Journal},
We show that the X-ray source W31 in the core of the globular cluster 47 Tucanae is physically associated with the bright blue straggler BSS 7. The two sources are astrometrically matched to 0061, with a chance coincidence probability of less than 1%. We then analyze optical time-series photometry obtained with the Hubble Space Telescope (HST) and find that BSS 7 displays a 1.56 day periodic signal in the I band. We also construct a broadband (far-ultraviolet through far-red) spectral energy… Expand
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