Guzik, JA, Houdek, G, Chaplin, WJ, Smalley, B ORCID: https://orcid.org/0000-0002-3456-087X, Kurtz, DW, Gilliland, RL, Mullally, F, Rowe, JF, Bryson, ST, Still, MD, Antoci, V, Appourchaux, T, Basu, S, Bedding, TR, Benomar, O, Garcia, RA, Huber, D, Kjeldsen, H, Latham, DW, Metcalfe, TS, Papics, PI, White, TR, Aerts, C, Ballot, J, Boyajian, TS, Briquet, M, Bruntt, H, Buchhave, LA, Campante, TL, Catanzaro, G, Christensen-Dalsgaard, J, Davies, GR, Dogan, G, Dragomir, D, Doyle, AP, Elsworth, Y, Frasca, A, Gaulme, P, Gruberbauer, M, Handberg, R, Hekker, R, Karoff, C, Lehmann, H, Mathias, P, Mathur, S, Miglio, A, Molenda-Zakowicz, J, Mosser, B, Murphy, SJ, Regulo, C, Ripepi, V, Salabert, D, Sousa, SG, Stello, D and Uytterhoeven, K (2016) Detection of Solar-Like Oscillations, Observational Constraints, and Stellar Models for theta Cyg, the Brightest Star Observed by the Kepler Mission. The Astrophysical Journal: an international review of astronomy and astronomical physics, 831 (1).

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Abstract

θ Cygni is an F3 spectral type magnitude V = 4.48 main-sequence star that was the brightest star observed by the original Kepler spacecraft mission. Short-cadence (58.8 s) photometric data using a custom aperture were first obtained during Quarter 6 (2010 June–September) and subsequently in Quarters 8 and 12–17. We present analyses of solar-like oscillations based on Q6 and Q8 data, identifying angular degree l = 0, 1, and 2 modes with frequencies of 1000–2700 μHz, a large frequency separation of 83.9 ± 0.4 μHz, and maximum oscillation amplitude at frequency ν max = 1829 ± 54 μHz. We also present analyses of new ground-based spectroscopic observations, which, combined with interferometric angular diameter measurements, give T eff = 6697 ± 78 K, radius 1.49 ± 0.03 R ⊙, [Fe/H] = −0.02 ± 0.06 dex, and log g = 4.23 ± 0.03. We calculate stellar models matching these constraints using the Yale Rotating Evolution Code and the Asteroseismic Modeling Portal. The best-fit models have masses of 1.35–1.39 M ⊙ and ages of 1.0–1.6 Gyr. θ Cyg's T eff and log g place it cooler than the red edge of the γ Doradus instability region established from pre-Kepler ground-based observations, but just at the red edge derived from pulsation modeling. The pulsation models show γ Dor gravity modes driven by the convective blocking mechanism, with frequencies of 1–3 cycles per day (11 to 33 μHz). However, gravity modes were not seen in Kepler data; one signal at 1.776 cycles per day (20.56 μHz) may be attributable to a faint, possibly background, binary.

Item Type: Article
Additional Information: Guzik, J.A. et al., 2016. DETECTION OF SOLAR-LIKE OSCILLATIONS, OBSERVATIONAL CONSTRAINTS, AND STELLAR MODELS FOR θ CYG, THE BRIGHTEST STAR OBSERVED BY THE KEPLER MISSION. The Astrophysical Journal, 831(1), p.17. Available at: http://dx.doi.org/10.3847/0004-637x/831/1/17, © 2016. The American Astronomical Society.
Uncontrolled Keywords: asteroseismology, stars, fundamental parameters, stars, interiors, stars, solar-type
Subjects: Q Science > QB Astronomy
Divisions: Faculty of Natural Sciences > School of Physical and Geographical Sciences
Depositing User: Symplectic
Date Deposited: 31 Aug 2016 11:04
Last Modified: 08 Apr 2019 09:09
URI: http://eprints.keele.ac.uk/id/eprint/2140

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