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Article Dans Une Revue The Astrophysical Journal Année : 2010

Solar-like Oscillations in Low-luminosity Red Giants: First Results from Kepler

Daniel Huber
Dennis Stello
Saskia Hekker
T. Kallinger
  • Fonction : Auteur
H. L. Preston
  • Fonction : Auteur
A. M. Broomhall
  • Fonction : Auteur
D. L. Buzasi
  • Fonction : Auteur
M. Gruberbauer
  • Fonction : Auteur
S. J. Hale
  • Fonction : Auteur
J. de Ridder
  • Fonction : Auteur
L. Bildsten
  • Fonction : Auteur
A. Derekas
  • Fonction : Auteur
M.-A. Dupret
  • Fonction : Auteur
A. Hatzes
  • Fonction : Auteur
G. Houdek
  • Fonction : Auteur
M. J. Ireland
  • Fonction : Auteur
C. Jiang
  • Fonction : Auteur
L. L. Kiss
  • Fonction : Auteur
Yveline Lebreton
M. D. Suran
  • Fonction : Auteur
N. J. Tarrant
  • Fonction : Auteur

Résumé

We have measured solar-like oscillations in red giants using time-series photometry from the first 34 days of science operations of the Kepler Mission. The light curves, obtained with 30 minute sampling, reveal clear oscillations in a large sample of G and K giants, extending in luminosity from the red clump down to the bottom of the giant branch. We confirm a strong correlation between the large separation of the oscillations (Δν) and the frequency of maximum power (νmax). We focus on a sample of 50 low-luminosity stars (νmax > 100 μHz, L <~ 30 L sun) having high signal-to-noise ratios and showing the unambiguous signature of solar-like oscillations. These are H-shell-burning stars, whose oscillations should be valuable for testing models of stellar evolution and for constraining the star formation rate in the local disk. We use a new technique to compare stars on a single échelle diagram by scaling their frequencies and find well-defined ridges corresponding to radial and non-radial oscillations, including clear evidence for modes with angular degree l = 3. Measuring the small separation between l = 0 and l = 2 allows us to plot the so-called C-D diagram of δν02 versus Δν. The small separation δν01 of l = 1 from the midpoint of adjacent l = 0 modes is negative, contrary to the Sun and solar-type stars. The ridge for l = 1 is notably broadened, which we attribute to mixed modes, confirming theoretical predictions for low-luminosity giants. Overall, the results demonstrate the tremendous potential of Kepler data for asteroseismology of red giants.

Dates et versions

hal-00660340 , version 1 (16-01-2012)

Identifiants

Citer

Timothy R. Bedding, Daniel Huber, Dennis Stello, Yvonne P. Elsworth, Saskia Hekker, et al.. Solar-like Oscillations in Low-luminosity Red Giants: First Results from Kepler. The Astrophysical Journal, 2010, 713 (2), pp.L176-L181. ⟨10.1088/2041-8205/713/2/L176⟩. ⟨hal-00660340⟩
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