ASTEROSEISMOLOGY OF RED GIANTS FROM THE FIRST FOUR MONTHS OF KEPLER DATA: GLOBAL OSCILLATION PARAMETERS FOR 800 STARS

Journal Article · Wed Nov 10 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/723/2/1607· OSTI ID:21471223

Huber, D; Bedding, T R; Stello, D; White, T R ^[1]; Mosser, B ^[2]; Mathur, S ^[3]; Kallinger, T ^[4]; Hekker, S; Elsworth, Y P; Chaplin, W J; Hale, S J ^[5]; Buzasi, D L; Preston, H L ^[6]; De Ridder, J ^[7]; Gilliland, R L ^[8]; Kjeldsen, H; Christensen-Dalsgaard, J ^[9]; GarcIa, R A ^[10]; Borucki, W J ^[11]

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1. Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia)
2. LESIA, CNRS, Universite Pierre et Marie Curie, Universite Denis, Diderot, Observatoire de Paris, 92195 Meudon cedex (France)
3. High Altitude Observatory, NCAR, P.O. BOX 3000, Boulder, CO 80307 (United States)
4. Department of Physics and Astronomy, University of British Columbia, Vancouver, BC Canada (Canada)
5. School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)
6. Eureka Scientific, 2452 Delmer Street Suite 100, Oakland, CA 94602-3017 (United States)
7. Instituut voor Sterrenkunde, K.U. Leuven (Belgium)
8. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
9. Danish AsteroSeismology Centre (DASC), Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)
10. Laboratoire AIM, CEA/DSM-CNRS, Universite Paris 7 Diderot, IRFU/SAp, Centre de Saclay, 91191, Gif-sur-Yvette (France)
11. NASA Ames Research Center, MS 244-30, Moffett Field, CA 94035 (United States)

We have studied solar-like oscillations in {approx}800 red giant stars using Kepler long-cadence photometry. The sample includes stars ranging in evolution from the lower part of the red giant branch to the helium main sequence. We investigate the relation between the large frequency separation ({Delta}{nu}) and the frequency of maximum power ({nu}{sub max}) and show that it is different for red giants than for main-sequence stars, which is consistent with evolutionary models and scaling relations. The distributions of {nu}{sub max} and {Delta}{nu} are in qualitative agreement with a simple stellar population model of the Kepler field, including the first evidence for a secondary clump population characterized by M {approx}> 2 M{sub sun} and {nu}{sub max} {approx_equal} 40-110 {mu}Hz. We measured the small frequency separations {delta}{nu}{sub 02} and {delta}{nu}{sub 01} in over 400 stars and {delta}{nu}{sub 03} in over 40. We present C-D diagrams for l = 1, 2, and 3 and show that the frequency separation ratios {delta}{nu}{sub 02}/{Delta}{nu} and {delta}{nu}{sub 01}/{Delta}{nu} have opposite trends as a function of {Delta}{nu}. The data show a narrowing of the l = 1 ridge toward lower {nu}{sub max}, in agreement with models predicting more efficient mode trapping in stars with higher luminosity. We investigate the offset {epsilon} in the asymptotic relation and find a clear correlation with {Delta}{nu}, demonstrating that it is related to fundamental stellar parameters. Finally, we present the first amplitude-{nu}{sub max} relation for Kepler red giants. We observe a lack of low-amplitude stars for {nu}{sub max} {approx}> 110 {mu}Hz and find that, for a given {nu}{sub max} between 40 and 110 {mu}Hz, stars with lower {Delta}{nu} (and consequently higher mass) tend to show lower amplitudes than stars with higher {Delta}{nu}.

• OSTI ID: 21471223
• Journal Information: Astrophysical Journal, Vol. 723, Issue 2; Other Information: DOI: 10.1088/0004-637X/723/2/1607; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
HELIUM
LUMINOSITY
MAIN SEQUENCE STARS
OSCILLATIONS
PHOTOMETRY
RED GIANT STARS
SEISMOLOGY
STAR EVOLUTION
ELEMENTS
EVOLUTION
FLUIDS
GASES
GIANT STARS
NONMETALS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PHYSICS
RARE GASES
STARS