Asteroseismic inference on rotation, gyrochronology and planetary system dynamics of 16 Cygni

TL;DR

This study uses asteroseismology to determine the rotation and inclination of 16 Cyg A and B, providing insights into stellar evolution, gyrochronology calibration, and planetary system dynamics.

Contribution

It presents the first asteroseismic measurements of rotation periods and inclinations for 16 Cyg A and B, and discusses implications for gyrochronology and planetary system evolution.

Findings

Rotation periods: ~24 days for both stars.

Inclination angles: 56° for A, 36° for B.

Low obliquity of 16 Cyg B supports Kozai cycling and tidal theories.

Abstract

The solar analogs 16 Cyg A and 16 Cyg B are excellent asteroseismic targets in the \Kepler field of view and together with a red dwarf and a Jovian planet form an interesting system. For these more evolved Sun-like stars we cannot detect surface rotation with the current \Kepler data but instead use the technique of asteroseimology to determine rotational properties of both 16 Cyg A and B. We find the rotation periods to be $23.8^{+1.5}_{-1.8} \rm \, days$ and $23.2^{+11.5}_{-3.2} \rm \, days$, and the angles of inclination to be $56^{+6}_{-5} \, ^{\circ}$ and $36^{+17}_{-7} \, ^{\circ}$, for A and B respectively. Together with these results we use the published mass and age to suggest that, under the assumption of a solar-like rotation profile, 16 Cyg A could be used when calibrating gyrochronology relations. In addition, we discuss the known 16 Cyg B star-planet eccentricity and measured low obliquity which is consistent with Kozai cycling and tidal theory.