Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/ftp/stsci/library/abstracts/1160.abs Дата изменения: Wed Jul 2 18:30:58 1997 Дата индексирования: Sun Dec 23 00:21:19 2007 Кодировка: Поисковые слова: с р р с с п п р п п с с с р р р р р п п р р р п п р

\documentstyle{preprint}
\newcommand{\Rs}{R$_{\odot}$}
\newcommand{\Md}{$\rm \dot{M}$}
\begin{document}

\title{A SPECTRAL ANALYSIS OF HDE269445 FROM OPTICAL\\
~\\
AND INFRARED OBSERVATIONS\thanks{Based on observations obtained
at the European Southern Observatory, La Silla}}
\author{A.~Pasquali\\
\\
Space Telescope Science Institute\\
3700 San Martin Drive, Baltimore, MD 21218\\
\and
W.~Schmutz\\
\\
Institut f\"ur Astronomie, ETH-Zentrum\\
CH-8092 Z\"urich, Switzerland\\
\and
A.~Nota\/\thanks{Affiliated with the Astrophysics Division, Space
Science Department of the European Space Agency}\\
\\
Space Telescope Science Institute\\
3700 San Martin Drive, Baltimore, MD 21218\\
\and
L.~Origlia\\
\\
Osservatorio Astronomico di Torino, Italy}

\pub{Astronomy and Astrophysics}
\recacc{6 February 1997}{9 May 1997}
\maketitle
\begin{abstract}
We present new, near-IR spectroscopic observations of HDE269445,
which we combine with published {\it HST\/} and IUE ultraviolet data and
optical high resolution spectra. We discuss the spectral morphology of the
star from UV to near-IR wavelengths, concentrating on profile variations
in the UV and optical H and He lines. From a spectroscopic analysis with
non-LTE model atmospheres, we derive for HDE269445: T$_{\star}$ = 34000~K,
R$_{\star}$ = 43 \Rs, log\Md(M$_\odot$/yr) = -4.5 and He/H = 0.4/0.6 by
number. These parameters are in good agreement with those previously derived
by Pasquali {\it et~al.} (1997) who used only ultraviolet and optical lines.
Therefore, our analysis confirms that a combination of optical and infrared
lines can be fruitfully used to determine stellar and wind properties when
ultraviolet data are not available.

Our model calculations only fit the broad component underneath a strong
core emission. We interpret the discrepancy between the observed and the
model line profiles as the effect of a non-spherical wind which has a hot,
fast polar component and a cold, slow equatorial component. The
time-variability detected in some H and He lines indicates that the wind
geometry may be variable and the star has undergone changes in T$_{ef\!f}$
and \Md. These properties are similar to those observed for the galactic
LBV AG~Carinae by Leitherer {\it et~al.} (1994) and we may suspect that
HDE269445 is also a Luminous Blue Variable. This could explain why HDE269445
has defied easy spectral classification, and, although originally classified
as a Ofpe/WN9, it has always represented a peculiarity for this spectral type.
\end{abstract}
\end{document}