EPJ Web of Conferences
Volume 43, 201340th Liège International Astrophysical Colloquium. Ageing Low Mass Stars: From Red Giants to White Dwarfs
|Number of page(s)||10|
|Published online||21 March 2013|
Amplitudes of solar-like oscillations in red giants: Departures from the quasi-adiabatic approximation
1 LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France
2 Institut d'Astrophysique et de Géophysique de l'Université de Liège, Allée du 6 Août, 17, 4000 Liège, Belgium
3 Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Knigstuhl 12, 69117 Heidelberg, Germany
4 Institut d'Astrophysique Spatiale, CNRS, Université Paris XI, 91405 Orsay Cedex, France
5 GEPI, CNRS, Observatoire de Paris, Université Denis Diderot, Place Jules Janssen, 92195 Meudon Cedex, France
a e-mail: email@example.com
CoRoT and Kepler measurements reveal us that the amplitudes of solar-like oscillations detected in red giant stars scale from stars to stars in a characteristic way. This observed scaling relation is not yet fully understood but constitutes potentially a powerful diagnostic about mode physics. Quasi-adiabatic theoretical scaling relations in terms of mode amplitudes result in systematic and large differences with the measurements performed for red giant stars. The use of a non-adiabatic intensity-velocity relation derived from a non-adiabatic pulsation code significantly reduces the discrepancy with the CoRoT measurements. The origin of the remaining difference is still unknown. Departure from adiabatic eigenfunction is a very likely explanation that is investigated in the present work using a 3D hydrodynamical model of the surface layers of a representative red giant star.
© Owned by the authors, published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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