Space- and ground-based pulsation data of [eta] Bootis explained with stellar models including turbulence

Abstract

The space telescope MOST is now providing us with extremely accurate low-frequency p-mode oscillation data for the star [eta] Boo.We demonstrate in this paper that these data, when combined with ground-based measurements of the high-frequency p-mode spectrum, can be reproduced with stellar models that include the effects of turbulence in their outer layers.Without turbulence, the l = 0 modes of our models deviate from either the ground-based or the space data by about 1.5–4 [mu]Hz. This discrepancy can be completely removed by including turbulence in the models, and we can exactly match 12 out of 13 MOST frequencies that we identified as l = 0 modes, in addition to 13 out of 21 ground-based frequencies within their observational 2 [sigma] tolerances. The better agreement between model frequencies and observed frequencies depends for the most part on the turbulent kinetic energy that was taken from a three-dimensional convection simulation for the Sun.