Core Overshoot: An Improved Treatment and Constraints from Seismic Data

  title={Core Overshoot: An Improved Treatment and Constraints from Seismic Data},
  author={Christian W. Straka and Pierre. Demarque and D. B. Guenther Institut fuer Theoretische Astrophysik and Universitaet Heidelberg and H Germany and Department of Physics Astronomy and Yale University and New Haven and Usa and Physics and Saint Mary's University and Halifax and Canada.},
  journal={The Astrophysical Journal},
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… Expand
We compare evolved stellar models, which match Procyon's mass and position in the HR diagram, to current ground-based asteroseismic observations. Diffusion of helium and metals along with twoExpand
Asteroseismology and evolutionary status of Procyon A
Models of Procyon A satisfying the actual observational constraints, particularly the asteroseismic ones, are discussed. The oscillations of these models were computed and analysed. We looked forExpand
Probing the properties of convective cores through g modes : high-order g modes in SPB and γ Doradus stars
In main-sequence stars, the periods of high-order gravity modes are sensitive probes of stellar cores and, in particular, of the chemical composition gradient that develops near the outer edge of theExpand
The Current Status of Asteroseismology
Stellar evolution, a fundamental bedrock of modern astrophysics, is driven by the physical processes in stellar interiors. While we understand these processes in general terms, we lack some importantExpand
Asteroseismic diagnostics of stellar convective cores
We present a detailed study of the small frequency separations as diagnostics of the mass of the convective core and evolutionary stage of solar-type stars. We demonstrate how the small separationsExpand
Constraining mixing processes in stellar cores using asteroseismology - Impact of semiconvection in low-mass stars
Context. The overall evolution of low-mass stars is heavily influenced by the processes occurring in the stellar interior. In particular, mixing processes in convectively unstable zones andExpand
Influence of the He-flash convective overshoot on mode trapping efficiency in g-mode pulsating subdwarf B stars
Recent detections of g-mode pulsations in subdwarf B (sdB) stars from the space missions CoRoT and Kepler have verified that nearly all of these pulsators have regular period spacings. This discoveryExpand
Investigating the Metallicity-Mixing Length Relation
Stellar models typically use the mixing length approximation as a way to implement convection in a simplified manner. While conventionally the value of the mixing length parameter, $\alpha$, used isExpand
Isochrones for late-type stars
  • P. Demarque
  • Geology
  • Proceedings of the International Astronomical Union
  • 2008
Abstract A brief summary of the history of stellar evolution theory and the use of isochrones is given. The present state of the subject is summarized. The major uncertainties in isochroneExpand
Probable nonradial g-mode pulsation in early A-type stars
Aims. Asteroseismology of early A-type stars could be a new tool to test stellar convection theories. Methods. A survey for line profile variability in early A-type stars has been performed in orderExpand


The Pulsation Properties of Procyon A.
It is found that g-modes are sensitive to model parameters that effect the structure of the core, such as convective core overshoot, the heavy-element abundance, and the evolutionary state (main sequence or shell hydrogen burning) of Procyon A. Expand
Evolution and Seismology of Procyon
We have calculated an array of stellar models for Procyon A that are based on the best physics available to us, including the latest opacities and nuclear cross sections. The array of models spansExpand
A Redetermination of the Mass of Procyon
The parallax and astrometric orbit of Procyon have been redetermined from PDS measurements of over 250 photographic plates spanning 83 years, with roughly 600 exposures used in the solution. TheseExpand
Detection of possible p-mode oscillations on Procyon
In the course of a search for solar-like oscillations in bright late-type stars, Doppler variability was observed in the F5 subgiant Procyon. The variations have frequencies within a 1.1 mHz rangeExpand
The Gap in the Color-Magnitude Diagram of NGC 2420: A Test of Convective Overshoot and Cluster Age
Theoretical isochrones have been constructed using the OPAL opacities specifically to study the color-magnitude diagram of the open star cluster NGC 2420. This cluster provides a rare test of coreExpand
Asteroseismology of the $\beta$ Cep star HD 129929 - II. Seismic constraints on core overshooting, internal rotation and stellar parameters
We perform a detailed seismic study of the β Cep star HD 129929. Our analysis is based on the recent derivation of six pulsation frequencies. These frequencies are unambiguously identified from theExpand
Convective overshoot mixing in old open clusters
THE ASTROPHYSICAL JOURNAL, 193: 109-111, 1974 October 1 © 1974. The American Astronomical Society. All rights reserved. Printed in USA. CONVECTIVE OVERSHOOT MIXING IN OLD OPEN CLUSTERS M. J. PRATHER*Expand
The diameter and evolutionary state of Procyon A. Multi-technique modeling using asteroseismic and i
We report the angular diameter measurement obtained with the VINCI/VLTI instrument on the nearby star Procyon A ( α  CMi A, F5IV–V), at a relative precision of ± 0.9%. We obtain a uniform diskExpand
The mass dependence of the overshooting parameter determined from eclipsing binary data
High-precision data on absolute dimensions of evolved eclipsing binaries have been used for a quantitative evaluation of the significance of convective overshoot in the stellar core. Eight detachedExpand
Updated Opal Opacities
The reexamination of astrophysical opacities has eliminated gross discrepancies between a variety of observations and theoretical calculations; thus allowing for more detailed tests of stellarExpand