The long term spectroscopic monitoring presented in this work and the comparison with the previous ones, show that V 380 Ori is a very active star. The many and somehow contrasting peculiarities of this star can be explained in the framework of a model of a central star plus accretion disk, as could be suggested in particular by the anomalous energy distribution. There are also evidences of the presence of outflowing matter from the star and/or from the disk.
The presence of an extended emitting region is supported by the many
broad metallic permitted lines that crowd the optical spectral region.
In particular, the width of the principal components of Fe II combined
with their large optical thickness and with the absence of
P Cygni absorptions in all lines but those of multiplet 42,
is interpreted as due to Keplerian motion in an accretion disk.
Assuming for the central star a mass of 3.3 
(Böhm & Catala 1995),
a value of 
cm is found
for the mean size of the Fe II emitting region.
A teneous high velocity wind is most probably causing the
few Fe II P Cygni absorptions.
The broad blue shifted emission components of Fe II
seem to be produced in a region less extended than that of the
principal components. Their blueshift
is about half that of the P Cygni absorption components
seen for the lines of multiplet 42 of Fe II.
It seems reasonable to suppose formation of the blue components
in the inner regions of the wind. In this case we would expect that
the emission from the receding matter is occulted by the disk,
in agreement with the accretion wind disk model proposed
by
Corcoran & Ray (1998).
A puzzling problem is represented by the ultraviolet spectral region where, neither the line spectrum, nor the interstellar extinction seem to agree with the optical data. The i.s. extinction law results to be anomalous and the only possible consistency with the optical EB-V value is obtained assuming that the strength of the 2175 Å band is much weaker than the galactic one. The line spectrum better fits a spectral type later than B9, and appears to be most probably produced by absorption in outer regions. Once the possible effect of the overlapping of absorption and emission components of metallic lines is taken into account, the UV continuum energy distribution appears to be in agreement with the stellar effective temperature.
The stellar activity is marked by the presence of the O I and Ca II emissions, and by the variability especially of the hydrogen and helium lines.
An intriguing feature is the He I 
5876 Å line, for which we
always detected an emission component, while in other epochs the line was
either only in absorption or not present at all.
We verified also on literature spectra that the helium absorpion lines,
when visible, always presented the same heliocentric radial velocity
(
45 km s-1);
this does not necessarily imply for the star a surface temperature higher
than that estimated from the photospheric absorptions profiles of Balmer
lines (10000 K).
Given the presence of an emission component, a chromospheric origin would
be a better explanation,
as suggested by
Böhm & Catala (1995)
for other Herbig Ae/Be stars.
Another possibility is the presence of a stationary hot circumstellar region.
Different solutions are possible to explain the emission component, variable both in intensity and in radial velocity, as for example the presence of an unstable hot region (hot spot?) close to the stellar surface, produced by irregular accretion processes. Alternatively, the He I emission might be produced by hot wind ejected mainly from the polar regions of the star or from the inner parts of a circumstellar disk in Keplerian rotation around the star (see also Böhm & Catala 1995). The width of the emissions (larger than the hydrogen lines) seems to favour the latter hypothesis. Hence the helium lines forming region is most probably located close to the star at the base of an accelerated wind which cools at larger distances where the Fe II blue components should be formed.
It would be important to give some more support to this possibility, looking for the variation of the blue Fe II emission component and by searching any correlation with the He I lines. We also think that the precise localization of the formation region and the time scales of the variability of the helium lines in the Herbig Ae/Be is an important problem in the framework of modelling the external layers, which would require high quality and systematic observations for all the stars of this category.
Acknowledgements
This research has made use of the Simbad database, operated at CDS, Strasbourg, France and f the archives of the Astronomical Data Center of the NASA Goddard Space Flight Center. We are grateful to Angelo Cassatella for discussions on the interstellar extinction law, We also thank the referee T. Böhm for a careful reading the manuscript and helpful suggestions, and to Herman Tijn A Djie for stimulating discussions. M. Friedjung, G. Muratorio, C. Rossi and R. Viotti were partially supported by the 1996-1997 CNR-CNRS exchange programme.
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