The age and stellar parameters of the Procyon binary system

James Liebert, Gilles Fontaine, Patrick A. Young, Kurtis A. Williams, W David Arnett

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The Procyon AB binary system (orbital period 40.838 yr, a newly refined determination) is near and bright enough that the component radii, effective temperatures, and luminosities are very well determined, although more than one possible solution to the masses has limited the claimed accuracy. Preliminary mass determinations for each component are available from Hubble Space Telescope imaging, supported by ground-based astrometry and an excellent Hipparcos parallax; we use these for our preferred solution for the binary system. Other values for the masses are also considered. We have employed the TYCHO stellar evolution code to match the radius and luminosity of the F5 IV-V primary star to determine the system's most likely age as 1.87 ± 0.13 Gyr. Since prior studies of Procyon A found its abundance indistinguishable from solar, the solar composition of Asplund, Grevesse, and Sauval (Z = 0.014) is assumed for the Hertzsprung-Russell diagram fitting. An unsuccessful attempt to fit using the older solar abundance scale of Grevesse & Sauval (Z = 0.019) is also reported. For Procyon B, 11 new sequences for the cooling of non-DA white dwarfs have been calculated to investigate the dependences of the cooling age on (1) the mass, (2) core composition, (3) helium layer mass, and (4) heavy-element opacities in the helium envelope. Our calculations indicate a cooling age of 1.19 ± 0.11 Gyr, which implies that the progenitor mass of Procyon B was 2.59+0.44-0.26 M. In a plot of initial versus final mass of white dwarfs in astrometric binaries or star clusters (all with age determinations), the Procyon B final mass lies several σ below a straight line fit.

Original languageEnglish (US)
Article number7
JournalAstrophysical Journal
Volume769
Issue number1
DOIs
StatePublished - May 20 2013

Fingerprint

cooling
helium
luminosity
Hertzsprung-Russell diagram
radii
astrometry
parameter
chronology
parallax
stellar evolution
star clusters
heavy elements
age determination
opacity
Hubble Space Telescope
envelopes
plots
diagram
stars
orbitals

Keywords

  • stars: atmospheres
  • stars: fundamental parameters
  • white dwarfs

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

The age and stellar parameters of the Procyon binary system. / Liebert, James; Fontaine, Gilles; Young, Patrick A.; Williams, Kurtis A.; Arnett, W David.

In: Astrophysical Journal, Vol. 769, No. 1, 7, 20.05.2013.

Research output: Contribution to journalArticle

Liebert, James ; Fontaine, Gilles ; Young, Patrick A. ; Williams, Kurtis A. ; Arnett, W David. / The age and stellar parameters of the Procyon binary system. In: Astrophysical Journal. 2013 ; Vol. 769, No. 1.
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