SOLAR-LIKE OSCILLATIONS IN LOW-LUMINOSITY RED GIANTS: FIRST RESULTS FROM KEPLER

Journal Article · Tue Apr 20 00:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/713/2/L176; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21305026

Bedding, T R; Huber, D; Stello, D ^[1]; Elsworth, Y P; Hekker, S; Broomhall, A M; Chaplin, W J; Hale, S J ^[2]; Kallinger, T ^[3]; Mathur, S ^[4]; Mosser, B; Barban, C ^[5]; Preston, H L; Buzasi, D L ^[6]; Ballot, J ^[7]; GarcIa, R A ^[8]; Gruberbauer, M ^[9]; De Ridder, J ^[10]; Frandsen, S ^[11]

---

1. Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia)
2. School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)
3. Department of Physics and Astronomy, University of British Columbia, Vancouver (Canada)
4. Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)
5. LESIA, CNRS, Universite Pierre et Marie Curie, Universite Denis, Diderot, Observatoire de Paris, 92195 Meudon Cedex (France)
6. Eureka Scientific, 2452 Delmer Street Suite 100, Oakland, CA 94602-3017 (United States)
7. Laboratoire d'Astrophysique de Toulouse-Tarbes Universite de Toulouse, CNRS 14 av E. Belin 31400 Toulouse (France)
8. Laboratoire AIM, CEA/DSM-CNRS, Universite Paris 7 Diderot, IRFU/SAp, Centre de Saclay, 91191, Gif-sur-Yvette (France)
9. Department of Astronomy and Physics, Saint Mary's University, Halifax, NS B3H 3C3 (Canada)
10. Instituut voor Sterrenkunde, K.U.Leuven (Belgium)
11. Danish AsteroSeismology Centre (DASC), Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

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 ({delta}{nu}) and the frequency of maximum power ({nu}{sub max}). We focus on a sample of 50 low-luminosity stars ({nu}{sub max} > 100 {mu}Hz, L {approx}< 30 L {sub 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 echelle 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 {delta}{nu}{sub 02} versus {delta}{nu}. The small separation {delta}{nu}{sub 01} 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.

• OSTI ID: 21305026
• Journal Information: Astrophysical Journal Letters, Vol. 713, Issue 2; Other Information: DOI: 10.1088/2041-8205/713/2/L176; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
LUMINOSITY
OSCILLATIONS
PHOTOMETRY
RED GIANT STARS
SIGNAL-TO-NOISE RATIO
STAR EVOLUTION
SUN