Outer atmospheres of cool stars. III. IUE spectra and transition region models for alpha Centauri A and B

Journal Article · Tue Jan 01 00:00:00 EST 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157612· OSTI ID:5536124

Ayres, T R; Linsky, J L

We describe IUE ultraviolet spectra of two nearby dwarf stars, ..cap alpha.. Centauri A (G2 V) and B (K1 V). These data include high-resolution profiles of the Mg II h and k features and lower-resolution integrated fluxes of lines from the following species: H I, C I--IV, N V, O I, Al II, Si II--IV, and Fe II. We find that surface fluxes in chromospheric and transition-region lines of ..cap alpha.. Cen A and B are nearly identical to those of the quiet Sun. In addition, the measured stellar line fluxes are in good agreement with predictions of a transition-region scaling law based on conductive heating and pressures estimated from chromospheric models of ..cap alpha.. Cen A and B. While this agreement does not verify the conductive heating hypothesis, it does suggest that the basic physical processes that control the structure and energy balance in the chromospheres and transition regions of ..cap alpha.. Cen A and B and the Sun are, on a gross scale, very likely the same.

• Research Organization: Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards, Boulder, Colorado
• OSTI ID: 5536124
• Journal Information: Astrophys. J.; (United States), Vol. 235:1
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DWARF STARS
STELLAR ATMOSPHERES
ULTRAVIOLET SPECTRA
BINARY STARS
EMISSION SPECTRA
MAGNESIUM IONS
RADIATION FLUX
ATMOSPHERES
ATOMIC IONS
CHARGED PARTICLES
IONS
SPECTRA
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources