Solar-like oscillations in low-luminosity red giants: First results from kepler

T. R. Bedding, D. Huber, D. Stello, Y. P. Elsworth, S. Hekker, T. Kallinger, S. Mathur, B. Mosser, H. L. Preston, J. Ballot, C. Barban, A. M. Broomhall, D. L. Buzasi, W. J. Chaplin, R. A. García, M. Gruberbauer, S. J. Hale, J. De Ridder, S. Frandsen, W. J. BoruckiT. Brown, J. Christensen-Dalsgaard, R. L. Gilliland, J. M. Jenkins, H. Kjeldsen, D. Koch, K. Belkacem, L. Bildsten, H. Bruntt, T. L. Campante, S. Deheuvels, A. Derekas, M. A. Dupret, M. J. Goupil, A. Hatzes, G. Houdek, M. J. Ireland, C. Jiang, C. Karoff, L. L. Kiss, Y. Lebreton, A. Miglio, J. Montalbn, A. Noels, I. W. Roxburgh, V. Sangaralingam, I. R. Stevens, M. D. Suran, N. J. Tarrant, A. Weiss

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186 Scopus citations

Abstract

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 ≲ 30L) 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.

Original languageEnglish (US)
Pages (from-to)L176-L181
JournalAstrophysical Journal Letters
Volume713
Issue number2 PART 2
DOIs
StatePublished - 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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