Rotational splitting as a function of mode frequency for six Sun-like stars

TL;DR

This study measures rotational splitting in six Sun-like stars using Kepler data, finding results consistent with uniform rotation and excluding significant radial differential rotation, thus advancing understanding of stellar internal rotation.

Contribution

First to measure rotational splitting across multiple Sun-like stars with high precision, constraining their internal rotation profiles using a robust MCMC approach.

Findings

Measured rotational splittings consistent with uniform rotation

Excluded large radial differential rotation in all six stars

Demonstrated the feasibility of constraining internal stellar rotation

Abstract

Asteroseismology offers the prospect of constraining differential rotation in Sun-like stars. Here we have identified six high signal-to-noise main-sequence Sun-like stars in the Kepler field, which all have visible signs of rotational splitting of their p-mode frequencies. For each star, we extract the rotational frequency splitting and inclination angle from separate mode sets (adjacent modes with l=2, 0, and 1) spanning the p-mode envelope. We use a Markov chain Monte Carlo method to obtain the best fit and errors associated with each parameter. We are able to make independent measurements of rotational splittings of ~8 radial orders for each star. For all six stars, the measured splittings are consistent with uniform rotation, allowing us to exclude large radial differential rotation. This work opens the possibility of constraining internal rotation of Sun-like stars.