Astronomy and Astrophysics, volume 413, 251-256 (2004/1-1)
The diameter and evolutionary state of Procyon A. Multi-technique modeling using asteroseismic and interferometric constraints.
KERVELLA P., THEVENIN F., MOREL P., BERTHOMIEU G., BORDE P. and PROVOST J.
Abstract (from CDS):
We report the angular diameter measurement obtained with the VINCI/VLTI instrument on the nearby star ProcyonA (αCMiA, F5IV-V), at a relative precision of ±0.9%. We obtain a uniform disk angular diameter in the K band of θUD
=5.376±0.047mas and a limb darkened value of θLD
=5.448±0.053mas. Together with the hipparcos parallax, this gives a linear diameter of 2.048±0.025D☉
. We use this result in combination with spectroscopic, photometric and asteroseismic constraints to model this star with the CESAM code. One set of modeling parameters that reproduces the observations within their error bars are an age of 2314Myr, an initial helium mass fraction Yi
=0.301 and an initial mass ratio of heavy elements to hydrogen ((Z/X)i
=0.0314. We also computed the adiabatic oscillation spectrum of our model of ProcyonA, giving a mean large frequency separation of <Δν0
≥∼54.7µHz. This value is in agreement with the seismic observations by Martic et al. (1999A&A...351..993M
, 2001, in SOHO 10/ GONG 2000 Workshop, ed. A. Wilson, ESA SP-464, 431). The interferometric diameter and the asteroseismic large frequency spacing together suggest a mass closer to 1.4M☉
than to 1.5M☉
. We conclude that Procyon is currently ending its life on the main sequence, as its luminosity class indicates.
stars: individual: α CMi - stars: fundamental parameters - stars: evolution - techniques: interferometric
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