Amplitudes of Solar-like Oscillations: Constraints from Red Giants in Open Clusters Observed by Kepler

Author(s)
Dennis Stello, Daniel Huber, Thomas Kallinger, Sarbani Basu, Benoît Mosser, Saskia Hekker, Savita Mathur, Rafael A. García, Timothy R. Bedding, Hans Kjeldsen, Ronald L. Gilliland, Graham A. Verner, William J. Chaplin, Othman Benomar, Søren Meibom, Frank Grundahl, Yvonne P. Elsworth, Joanna Molenda-Żakowicz, Robert Szabó, Jørgen Christensen-Dalsgaard, Peter Tenenbaum, Joseph D. Twicken, Kamal Uddin
Abstract

Scaling relations that link asteroseismic quantities to global stellar properties are important for gaining understanding of the intricate physics that underpins stellar pulsations. The common notion that all stars in an open cluster have essentially the same distance, age, andinitial composition implies that the stellar parameters can be measured to much higher precision than what is usually achievable for single stars. This makes clusters ideal for exploring the relation between the mode amplitude of solar-like oscillations and the global stellar properties. We have analyzed data obtained with NASA's Kepler space telescope to study solar-like oscillations in 100 red giant starslocated in either of the three open clusters, NGC 6791, NGC 6819, and NGC 6811. By fitting the measured amplitudes to predictions from simple scaling relations that depend on luminosity, mass, and effective temperature, we find that the data cannot be described by any power ofthe luminosity-to-mass ratio as previously assumed. As a result we provide a new improved empirical relation which treats luminosity and mass separately. This relation turns out to also work remarkably well for main-sequence and subgiant stars. In addition, the measured amplitudes reveal the potential presence of a number of previously unknown unresolved binaries in the red clump in NGC 6791 and NGC 6819,pointing to an interesting new application for asteroseismology as aprobe into the formation history of open clusters.

Organisation(s)
Department of Astrophysics
External organisation(s)
The University of Sydney, University of British Columbia (UBC), Yale University, Université de recherche Paris Sciences et Lettres, University of Amsterdam (UvA), National Center for Atmospheric Research (NCAR), Université Paris VII - Paris-Diderot, Aarhus University, Space Telescope Science Institute, University of Birmingham, Queen Mary University of London, Harvard-Smithsonian Center for Astrophysics, University of Wrocław, Hungarian Academy of Sciences, National Aeronautics & Space Administration (NASA)
Journal
The Astrophysical journal Letters
Volume
737
ISSN
2041-8205
DOI
https://doi.org/10.1088/2041-8205/737/1/L10
Publication date
08-2011
Peer reviewed
Yes
Austrian Fields of Science 2012
103004 Astrophysics
Keywords
Portal url
https://ucrisportal.univie.ac.at/en/publications/5390518c-c8fd-434d-b2ae-862077e307d1