Travis Metcalfe & KASC

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


<ul><li><p>Travis Metcalfe &amp; KASC Asteroseismology of 16 Cyg A &amp; 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)</p></li><li><p>Sun in timeGuinan &amp; Engel (2009)Li, Pcyc</p></li><li><p>Binary orbitV~6, extremely saturated</p></li><li><p>Exoplanet orbitCochran et al. (1997)</p></li><li><p>Chromospheric activityHall et al. (2007)</p></li><li><p>Solar-like oscillationstgran = 257 6 sectgran = 241 8 sec</p></li><li><p> 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)</p></li><li><p>Stellar evolution tracks from ASTEC, pulsation analysis with ADIPLS</p><p>Parallel genetic algorithm optimizes globally, local analysis + SVD for errors</p><p>Stellar age from match to large separation, correct surface effects empirically</p><p> 0.75 &lt; M &lt; 1.75 0.002 &lt; Z &lt; 0.05 0.22 &lt; Y &lt; 0.32 1.0 &lt; a &lt; 3.0Metcalfe et al. (2009), Woitaszek et al. (2009) Modeling Portal</p></li><li><p>(Differential) rotation: very low magnetic activity levels make spot modeling a challenge, but longer data sets should resolve mode splitting.</p><p>Convection zone depth: oscillatory signatures in D2n from acoustic glitches (due to CZ and He II) should be detectable with ~1 year time series.</p><p>Long-term variations: extended time series will allow the detection of secular (and periodic) variations in the frequencies, amplitudes, etc. Future prospects</p></li><li><p>Thanks to the international sponsor of the Kepler Asteroseismic Science Consortium</p></li></ul>