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\begin{document} 
\title{THE BIPOLAR HR CARINAE NEBULA:\\
~\\
DYNAMICS AND CHEMICAL ABUNDANCES\thanks{Based on observations obtained at the 
European Southern Observatory, La Silla}}
\author{Antonella 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\\ 
email: nota@stsci.edu\\
\\
\and
Linda Smith\\
\\
Department of Physics and Astronomy, University College London\\
Gower Street, London WC1E 6BT, United Kingdom\\
email: ljs@star.ucl.ac.uk\\
\and
Anna Pasquali, Mark Clampin\\
\\
Space Telescope Science Institute\\
email: pasquali@stsci.edu, clampin@stsci.edu\\ 
\and
Matthew Stroud\\
\\
Department of Physics and Astronomy, University College London\\
email: mps@star.ucl.ac.uk}

\pub{The Astrophysical Journal}
\recacc{18 November 1996}{29 January 1997}
\maketitle 

\end{document}

\abstract{We present the results of a new set of  medium resolution
spectroscopic observations  and high resolution coronographic images of
the nebula around the  galactic Luminous Blue Variable (LBV) HR
Carinae. The observations were carried out at the  ESO/NTT  (La~Silla)
in May 1995 and January 1996. The nebular morphology and kinematics
confirm that  the nebula around HR Carinae is truly bipolar, and very
reminiscent of the $\eta$ Carinae nebula.  The previously identified  {\it
``filaments''\/} outline the edges of two symmetrical expanding bubbles,
originating from the star and located respectively in the NW and SE
quadrants. The small compact  inner nebula, a few arcseconds in size,
previously detected,  represents the  {\it ``waist''\/} of the bipolar
distribution. The orientation in the images and the kinematical study
have allowed us to define the true orientation of the bubbles, whose
major axis lies  at an angle of $\simeq50^{\rm o}$ with the plane of the
sky, at an inclination of approximately $30^{\rm o}$ on the line of sight.
The maximum projected expansion velocity is of the order of $\simeq100$~km/s. 
In the light of these new kinematical data, we revise the
dynamical timescale to a  younger age of $\simeq5000$~yrs.

The nebula around HR~Carinae is relatively young and fast, at variance
with other well known LBV nebulae such as AG~Carinae's.
Spectroscopically, the nebula is of low excitation with \mbox{[OIII]} absent,
and \mbox{[NII]} fairly strong. \mbox{[NiII]} $\lambda6667$ is detected, but 
only in the inner regions ($\le 5''$).  We find that the electron density
increases from 400~cm$^{-3}$ in the outer regions to $> 10^4$~cm$^{-3}$
in the innermost regions. An analysis of the chemical abundances in
different regions of the nebula finds that N is overabundant,
indicating that the nebula is composed of CNO processed stellar
material.  We find that the filamentary HII region, seen to the NW of
HR~Carinae, is at the same distance and is composed of material with
typical HII region abundances, and has a morphology that suggests it
has been shaped by the wind of HR~Carinae.}