Multisite campaign on the open cluster M67. III. Delta Scuti pulsations in the blue stragglers
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 meter telescopes with a time baseline of 43 days. In two stars, EW Cnc and EX Cnc, we detect the highest number of frequencies (41 and 26) detected in delta Scuti stars belonging to a stellar cluster, and EW Cnc has the second highest number of frequencies detected in any delta 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 show 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 either from multi-colour photometry or spectroscopy.
Keywords
Cite
@article{arxiv.0704.3884,
title = {Multisite campaign on the open cluster M67. III. Delta Scuti pulsations in the blue stragglers},
author = {H. Bruntt and D. Stello and J. C. Suarez and T. Arentoft and T. R. Bedding and M. Y. Bouzid and Z. Csubry and T. H. Dall and Z. E. Dind and S. Frandsen and R. L. Gilliland and A. P. Jacob and H. R. Jensen and Y. B. Kang and S. -L. Kim and L. L. Kiss and H. Kjeldsen and J. -R. Koo and J. -A. Lee and C. -U. Lee and J. Nuspl and C. Sterken and R. Szabo},
journal= {arXiv preprint arXiv:0704.3884},
year = {2009}
}
Comments
15 pages, 14 figs, one appendix. Part three in a series of papers describing results from an extensive multi-site campaign on the open cluster M67