Asteroseismic analysis of the CoRoT target HD49933

Abstract

The frequency ratios and of HD 49933 exhibit an increase at high frequencies. This behavior also exists in the ratios of other stars, which is considered to result from the low signal-to-noise ratio and the larger line width at the high-frequency end and could not be predicted by stellar models in previous work. Our calculations show that the behavior not only can be reproduced by stellar models, but can be predicted by asymptotic formulas of the ratios. The frequency ratios of the Sun, too, can be reproduced well by the asymptotic formulas. The increased behavior derives from the fact that the gradient of mean molecular weight at the bottom of the radiative region hinders the propagation of p-modes, while the hindrance does not exist in the convective core. This behavior should exist in the ratios of stars with a large convective core. The characteristic of the ratios at high frequencies provides a strict constraint on stellar models and aids in determining the size of the convective core and the extent of overshooting. Observational constraints point to a star with $M=1.28\pm 0.01M_{\odot }$, $R=1.458\pm 0.005R_{\odot }$, $t=1.83\pm 0.1$ Gyr, $r_{cc}=0.16\pm 0.02R_{\odot }$, $\alpha =1.85\pm 0.05$, and ${\delta }_{ov}=0.6\pm 0.2$ for HD 49933.

Accepted for publication in ApJ. Any comments are welcome and please send to [email protected]

References in corpus (10)

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• Convective overshoot mixing in stellar interior models
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• Convective boundary mixing in low- and intermediate-mass stars I. Core properties from pressure-mode asteroseismology
• Main Sequence Evolution with Layered Semiconvection
• The effects of the overshooting of the convective core on main-sequence turnoffs of young- and intermediate-age star clusters
• Asteroseismic analysis of Kepler target KIC 2837475
• Asteroseismology of main-sequence F stars with \textit{Kepler}: overcoming short mode lifetimes
• Seismic diagnostics of solar-like oscillating stars
• Estimate the radius of the convective core of main-sequence stars from observed oscillation frequencies
• Impact of convective overshooting on the single-degenerate model of Type Ia supernovae
• Exploring the sources of p-mode frequency shifts in the CoRoT target HD 49933
• The SAPP pipeline for the determination of stellar abundances and atmospheric parameters of stars in the core program of the PLATO mission