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Asteroseismic measurement of slow, nearly uniform surface-to-core rotation in the main-sequence F star KIC 9244992

Hideyuki Saio1Astronomical Institute, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, JapanD. W. Kurtz2Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UKM. Takata3Department of Astronomy, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, JapanHiromoto Shibahashi3Department of Astronomy, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, JapanSimon J. Murphy5Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Aarhus C, DK-8000, DenmarkT. Sekii6National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, JapanT. R. Bedding5Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Aarhus C, DK-8000, Denmark

2015en

ABI

Annotatsiya

We have found a rotationally split series of core g-mode triplets and surface p-mode multiplets in a main-sequence F star, KIC 9244992. Comparison with models shows that the star has a mass of about 1.45 M⊙, and is at an advanced stage of main-sequence evolution in which the central hydrogen abundance mass fraction is reduced to about 0.1. This is the second case, following KIC 11145123, of an asteroseismic determination of the rotation of the deep core and surface of an A-F main-sequence star. We have found, essentially model independently, that the rotation near the surface, obtained from p-mode splittings, is 66 d, slightly slower than the rotation of 64 d in the core, measured by g-mode splittings. KIC 9244992 is similar to KIC 11145123 in that both are near the end of main-sequence stage with very slow and nearly uniform rotation. This indicates the angular momentum transport in the interior of an A-F star during the main-sequence stage is much stronger than that expected from standard theoretical formulations.

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DOI: 10.1093/mnras/stu2696

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