Multisite campaign on the open cluster M67 - III. δ Scuti pulsations in the blue stragglers

H. Bruntt, D. Stello, J. C. Suárez, T. Arentoft, T. R. Bedding, M. Y. Bouzid, Z. Csubry, T. H. Dall, Z. E. Dind, S. Frandsen, R. L. Gilliland, A. P. Jacob, H. R. Jensen, Y. B. Kang, S. L. Kim, L. L. Kiss, H. Kjeldsen, J. R. Koo, J. A. Lee, C. U. LeeJ. Nuspl, C. Sterken, R. Szabó

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Abstract

We have made an asteroseismic analysis of the variable blue stragglers in the open cluster M67. The data set consists of photometric time-series from eight sites using nine 0.6-2.1 m telescopes with a time-baseline of 43 d. In two stars, EW Cnc and EX Cnc, we detect the highest number of frequencies (41 and 26) detected in δ Scuti stars belonging to a stellar cluster, and EW Cnc has the second highest number of frequencies detected in any δ Scuti star. We have computed a grid of pulsation models that take the effects of rotation into account. The distribution of observed and theoretical frequencies shows that in a wide frequency range a significant fraction of the radial and non-radial low-degree modes are excited to detectable amplitudes. Despite the large number of observed frequencies we cannot constrain the fundamental parameters of the stars. To make progress we need to identify the degrees of some of the modes from either multicolour photometry or spectroscopy.

Original languageEnglish
Pages (from-to)1371-1384
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume378
Issue number4
DOIs
Publication statusPublished - Jul 1 2007

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Keywords

  • Blue stragglers
  • Open clusters and associations: individual: M67 (NGC 2682)
  • Stars: individual: EW Cnc
  • Stars: individual: EX Cnc
  • δ Scuti

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Bruntt, H., Stello, D., Suárez, J. C., Arentoft, T., Bedding, T. R., Bouzid, M. Y., Csubry, Z., Dall, T. H., Dind, Z. E., Frandsen, S., Gilliland, R. L., Jacob, A. P., Jensen, H. R., Kang, Y. B., Kim, S. L., Kiss, L. L., Kjeldsen, H., Koo, J. R., Lee, J. A., ... Szabó, R. (2007). Multisite campaign on the open cluster M67 - III. δ Scuti pulsations in the blue stragglers. Monthly Notices of the Royal Astronomical Society, 378(4), 1371-1384. https://doi.org/10.1111/j.1365-2966.2007.11865.x