Bibcode
DOI
Allende Prieto, Carlos; Lambert, David L.
Bibliographical reference
The Astronomical Journal, Volume 119, Issue 5, pp. 2445-2454.
Advertised on:
5
2000
Citations
25
Refereed citations
23
Description
Analyses of the near-ultraviolet continuum of late-type stars have led
to controversial results regarding the performance of state-of-the-art
model atmospheres. The release of the homogeneous International
Ultraviolet Explorer (IUE) final archive and the availability of the
high-accuracy Hipparcos parallaxes provide an opportunity to revisit
this issue, as accurate stellar distances make it possible to compare
observed absolute fluxes with the predictions of model atmospheres. The
near-UV continuum is highly sensitive to Teff and [Fe/H], and
once the gravity is constrained from the parallax, these parameters may
be derived from the analysis of low-dispersion, long-wavelength
(2000-3000 Å) IUE spectra for stars previously studied by Alonso,
Arribas, & Martínez-Roger using the Infrared Flux Method
(IRFM). A second comparison is carried out against the stars
spectroscopically investigated by Gratton, Carretta, & Castelli. It
is shown that there is a good agreement between Teff values
obtained from the IRFM and those from the near-UV continuum, and a
remarkable correspondence between observed and synthetic fluxes for
stars with 4000 K<=Teff<=6000 K of any metallicity and
gravity. These facts suggest that model atmospheres provide an adequate
description of the near-UV continuum forming region and that the
opacities involved are essentially understood.