Sounding open clusters: Asteroseismic constraints from kepler on the properties of NGC6791 and NGC6819

Sarbani Basu, Frank Grundahl, Dennis Stello, Thomas Kallinger, Saskia Hekker, Benoit Mosser, Rafael A. García, Savita Mathur, Karsten Brogaard, Hans Bruntt, William J. Chaplin, Ning Gai, Yvonne Elsworth, Lisa Esch, Jerome Ballot, Timothy R. Bedding, Michael Gruberbauer, Daniel Huber, Andrea Miglio, Mutlu YildizHans Kjeldsen, Jørgen Christensen-Dalsgaard, Ronald L. Gilliland, Michael M. Fanelli, Khadeejah A. Ibrahim, Jeffrey C. Smith

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Abstract

We present initial results on some of the properties of open clusters NGC6791 and NGC6819 derived from asteroseismic data obtained by NASA's Kepler mission. In addition to estimating the mass, radius, and log g of stars on the red giant branch (RGB) of these clusters, we estimate the distance to the clusters and their ages. Our model-independent estimate of the distance modulus of NGC6791 is (m - M)0 = 13.11 0.06. We find (m - M)0 = 11.85 0.05 for NGC6819. The average mass of stars on the RGB of NGC6791 is 1.20 0.01 M, while that of NGC6819 is 1.68 0.03 M. It should be noted that we do not have data that cover the entire RGB and the actual mass will be somewhat lower. We have determined model-dependent estimates of ages of these clusters. We find ages between 6.8 and 8.6 Gyr for NGC6791, however, most sets of models give ages around 7 Gyr. We obtain ages between 2 and 2.4 Gyr for NGC6819.

Original languageEnglish (US)
Article numberL10
JournalAstrophysical Journal Letters
Volume729
Issue number1 PART II
DOIs
StatePublished - Mar 1 2011

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All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Basu, S., Grundahl, F., Stello, D., Kallinger, T., Hekker, S., Mosser, B., García, R. A., Mathur, S., Brogaard, K., Bruntt, H., Chaplin, W. J., Gai, N., Elsworth, Y., Esch, L., Ballot, J., Bedding, T. R., Gruberbauer, M., Huber, D., Miglio, A., ... Smith, J. C. (2011). Sounding open clusters: Asteroseismic constraints from kepler on the properties of NGC6791 and NGC6819. Astrophysical Journal Letters, 729(1 PART II), [L10]. https://doi.org/10.1088/2041-8205/729/1/L10