Asteroseismic Study of KIC 11145123: Its Structure and Rotation

Hatta, Yoshiki, Sekii, Takashi, Takata, Masao and Kurtz, Donald Wayne orcid iconORCID: 0000-0002-1015-3268 (2020) Asteroseismic Study of KIC 11145123: Its Structure and Rotation. In: Dynamics of the Sun and Stars. Springer, pp. 243-249. ISBN 978-3-030-55335-7

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Official URL: https://doi.org/10.1007/978-3-030-55336-4_32

Abstract

KIC 11145123 is one of the Kepler targets that has been actively studied asteroseismically. Its well-resolved frequency splittings for p, g, and mixed modes have enabled us to infer the 1-dimensional surface-to-core rotation of the star (Kurtz et al., Mon Not R Astron Soc 444:102, 2014) and to measure the asphericity of the star sensed by the modes (Gizon et al., Sci Adv 2:e1601777, 2016). These have been the first such attempts for main-sequence stars other than the Sun. In this paper, we report further detailed asteroseismic analyses of KIC 11145123, focusing on inferring 2-dimensional rotation profile and on fine-tuning the equilibrium model of the star. Our main results are: (1) the convective core might be rotating six times faster than the other parts of the star, and (2) adopting diffusion “weaker” than the usual settings used in the standard 1-d stellar evolution calculations leads to a better agreement with the observed g-mode period spacing pattern. These two results suggest that the rotational velocity shear might be causing some extra mixing around the boundary between convective core and radiative region above, and the extra mixing weakens, in effect, the diffusion process there. This resembles a mechanism thought to be at work around the solar tachocline.


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