Travis Metcalfe & KASC

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Asteroseismology of 16 Cyg A & B from Kepler observations. Travis Metcalfe & KASC. - PowerPoint PPT Presentation


Travis Metcalfe & KASC Asteroseismology of 16 Cyg A & B from Kepler observationsCollaborators: Sarbani Basu, Isa Brando, Bill Chaplin, Orlagh Creevey, Sebastien Deheuvels, Glnur Doan, Patrick Eggenberger, Christoffer Karoff, Andrea Miglio, Dennis Stello, Mutlu Yildiz et al. (KASC WG1)Sun in timeGuinan & Engel (2009)Li, PcycBinary orbitV~6, extremely saturatedExoplanet orbitCochran et al. (1997)Chromospheric activityHall et al. (2007)Solar-like oscillationstgran = 257 6 sectgran = 241 8 sec Fit each star independently, frequencies and spectroscopy Reproduce the same fit with several codes (for systematics) Best models have same age and composition (not forced) MA=1.11, MB=1.07, t=6.80.4 Gyr, Zi=0.02(42), Yi=0.2(51)Model-fitting resultsMetcalfe et al. (in prep)Stellar evolution tracks from ASTEC, pulsation analysis with ADIPLSParallel genetic algorithm optimizes globally, local analysis + SVD for errorsStellar age from match to large separation, correct surface effects empirically 0.75 < M < 1.75 0.002 < Z < 0.05 0.22 < Y < 0.32 1.0 < a < 3.0Metcalfe et al. (2009), Woitaszek et al. (2009) Modeling Portal(Differential) rotation: very low magnetic activity levels make spot modeling a challenge, but longer data sets should resolve mode splitting.Convection zone depth: oscillatory signatures in D2n from acoustic glitches (due to CZ and He II) should be detectable with ~1 year time series.Long-term variations: extended time series will allow the detection of secular (and periodic) variations in the frequencies, amplitudes, etc. Future prospectsThanks to the international sponsor of the Kepler Asteroseismic Science Consortium