2005ApJ...629.1075S -
Astrophys. J., 629, 1075-1090 (2005/August-3)
Core overshoot: an improved treatment and constraints from seismic data.
STRAKA C.W., DEMARQUE P. and GUENTHER D.B.
Abstract (from CDS):
We present a comprehensive set of stellar evolution models for Procyon A in an effort to guide future measurements of both traditional stellar parameters and seismic frequencies toward constraining the amount of core overshoot in Procyon A and possibly other stars. Current observational measurements of Procyon A when combined with traditional stellar modeling only place a large upper limit on overshoot of αOV<1.1. By carrying out a detailed pulsation analysis, we further demonstrate how p- and g-mode averaged spacings can be used to gain better estimates of the core size. For both p- and g-modes, the frequency spacings for models without overshoot are clearly separated from the models with overshoot. In addition, measurements of the l=0 averaged small p-mode spacings could be used to establish Procyon A's evolutionary stage. For a fixed implementation of overshoot and under favorable circumstances, the g-mode spacings can be used to determine the overshoot extent to an accuracy of ±0.05H_P_. However, we stress that considerable confusion is added due to the unknown treatment of the overshoot region. This ambiguity might be removed by analyzing many different stars. A simple nonlocal convection theory developed by Kuhfuss is implemented in our stellar evolution code and contrasted with the traditional approaches. We show that this theory supports a moderate increase of the amount of convective overshoot with stellar mass of ΔαOV≃+0.10 between 1.5 and 15 M☉. This theory places an upper limit on Procyon A's core overshoot extent of ∼0.4HP, which matches the limit imposed by Roxburgh's integral criterion.
Abstract Copyright:
∼
Journal keyword(s):
Convection - Stars: Evolution - Stars: Individual: Name: Procyon A - Stars: Interiors - Stars: Oscillations
Simbad objects:
3
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2005ApJ...629.1075S and select 'bookmark this link' or equivalent in the popup menu