Asteroseismology of a possible blue straggler star, KIC 11145123
Yoshiki Hatta (SOKENDAI/National Astronomical Observatory of Japan)
KIC 11145123 is a gamma Dor-delta Sct hybrid pulsator for which well-resolved frequency splittings for p, g, and mixed modes have been observed, leading to a number of detailed asteroseismic studies of the star such as stellar modeling and rotation inversion. All the previous models of the star have been constructed assuming single-star evolution. However, the star is spectroscopically considered a blue straggler, which is thought to have experienced some interactions with other stars. There is thus room for carrying out non-standard asteroseismic modeling of the star assuming non-single-star evolution.
In this talk, we primarily discuss a non-standard model of the star. Comparison of the non-standard model with the previous models suggests that the star may well have experienced some modifications of chemical compositions in the envelope during the evolution, consistent with formation channels of blue straggler stars.
We also would like to discuss the internal rotation profile of the star asteroseismically inferred based on the non-standard model. In particular, we focus on a detection of the fast-convective-core rotation in detail. A possible relation between the inferred fast-convective-core rotation and the structure in the deep radiative region of the star is investigated. Though we do not find a clear signature between the internal dynamics and structure of the star, this is the first study which tests the possibility that there is a relationship between the current rotational profile and the structure of stars other than the Sun, and to investigate such relationship should be one of the most highly prioritized subjects to future researches.