An Asteroseismic Membership Study of the Red Giants in Three Open Clusters Observed by Kepler: NGC 6791, NGC 6819, and NGC 6811
Dennis Stello
(1)
,
Søren Meibom
(2)
,
Ronald L. Gilliland
(3)
,
Frank Grundahl
(4)
,
Saskia Hekker
(5)
,
Benoît Mosser
(6, 7)
,
Thomas Kallinger
(8)
,
Savita Mathur
(9)
,
Rafael A. Garcia
(10)
,
Daniel Huber
(1)
,
Sarbani Basu
(11)
,
Timothy R. Bedding
(1)
,
K. Brogaard
(4)
,
William J. Chaplin
(5)
,
Yvonne P. Elsworth
(5)
,
Joanna Molenda-Zakowicz
(12)
,
Robert Szabó
(13)
,
Martin Still
(14)
,
Jon M. Jenkins
(15)
,
Jörgen Christensen-Dalsgaard
(4)
,
Hans Kjeldsen
(4)
,
Aldo Serenelli
(16)
,
Bill Wohler
(17)
1
SIfA -
Sydney Institute for Astronomy
2 CfA - Harvard-Smithsonian Center for Astrophysics
3 STSci - Space Telescope Science Institute
4 Aarhus University [Aarhus]
5 University of Birmingham [Birmingham]
6 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
7 Etoile
8 IfA - Institut für Astronomie, Universität Wien
9 High Altitude Observatory, National Center for Atmospheric Research
10 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
11 Yale University [New Haven]
12 Instytut Astronomiczny, Uniwersytet Wroclawski
13 Konkoly Observatory, Research Center for Astronomy and Earth Sciences
14 BAER - Bay Area Environmental Research Institute
15 SETI Institute, NASA Ames Research Center, Moffett Field
16 Instituto de Ciencias del Espacio-Institut d'Estudis Espacials de Catalunya
17 Orbital Sciences Corporation, NASA Ames Research Center, Moffett Field
2 CfA - Harvard-Smithsonian Center for Astrophysics
3 STSci - Space Telescope Science Institute
4 Aarhus University [Aarhus]
5 University of Birmingham [Birmingham]
6 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
7 Etoile
8 IfA - Institut für Astronomie, Universität Wien
9 High Altitude Observatory, National Center for Atmospheric Research
10 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
11 Yale University [New Haven]
12 Instytut Astronomiczny, Uniwersytet Wroclawski
13 Konkoly Observatory, Research Center for Astronomy and Earth Sciences
14 BAER - Bay Area Environmental Research Institute
15 SETI Institute, NASA Ames Research Center, Moffett Field
16 Instituto de Ciencias del Espacio-Institut d'Estudis Espacials de Catalunya
17 Orbital Sciences Corporation, NASA Ames Research Center, Moffett Field
Résumé
Studying star clusters offers significant advances in stellar astrophysics due to the combined power of having many stars with essentially the same distance, age, and initial composition. This makes clusters excellent test benches for verification of stellar evolution theory. To fully exploit this potential, it is vital that the star sample is uncontaminated by stars that are not members of the cluster. Techniques for determining cluster membership therefore play a key role in the investigation of clusters. We present results on three clusters in the Kepler field of view based on a newly established technique that uses asteroseismology to identify fore- or background stars in the field, which demonstrates advantages over classical methods such as kinematic and photometry measurements. Four previously identified seismic non-members in NGC 6819 are confirmed in this study, and three additional non-members are found---two in NGC 6819 and one in NGC 6791. We further highlight which stars are, or might be, affected by blending, which needs to be taken into account when analyzing these Kepler data.