SOUNDING OPEN CLUSTERS: ASTEROSEISMIC CONSTRAINTS FROM KEPLER ON THE PROPERTIES OF NGC 6791 AND NGC 6819
Makaleler > Tam Makale · 2011
Yazarlar: Sarbani Basu, Frank Grundahl, Dennis Stello, Thomas Kallinger, Saskia Hekker, Benoit MOSSER, Rafael A. GARCIA, 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 YILDIZ, Hans Kjeldsen, Jorgen Christensen-Dalsgaard, Ronald L. GILLILAND, Michael M. FANELLI, Khadeejah A. IBRAHIM, Jeffrey C. SMITH
The Astrophysical Journal, SCI Expanded İndekslerine Giren Dergi, Uluslararası, Wos, 2011, cilt 729, ss L10-L10
DOI: 10.1088/2041-8205/729/1/l10
Özet
We present initial results on some of the properties of open clusters NGC 6791 and NGC 6819 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 NGC 6791 is ( m − M ) 0 = 13.11 ± 0.06. We find ( m − M ) 0 = 11.85 ± 0.05 for NGC 6819. The average mass of stars on the RGB of NGC 6791 is 1.20 ± 0.01 M ☉ , while that of NGC 6819 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 NGC 6791, however, most sets of models give ages around 7 Gyr. We obtain ages between 2 and 2.4 Gyr for NGC 6819.