C. Gry 1, G. Pineau des Forêts 2, & C.M. Walmsley 3
1 LAS, BP 8, F-13376 Marseille cedex 12
2 DAEC, Observatoire de Paris, Place Janssen, 92190 Meudon, France
3 Osservatorio Astrofisico di Arcetri, Firenze, Italy
We have used the LWS in order to measure the atomic silicon
fine structure lines at 68.5 and 129.7 
towards the
Orion Kleinmann-Low nebula. We used the AOT LWS04 with a spectral
resolution of roughly 10000. At the wavelength of the 68.5
feature, we find a feature of intensity
(error
)
and of width corresponding to
the instrumental
resolution. The S/N achieved on the continuum is 700. At
the wavelength of the 129
line, we presently only derive an
upper limit. For temperatures above 100 K, we estimate
that our observed 68.5
feature corresponds to a SiI
column density in the range
to
as compared
with an ionized Si column density (from observations of the SiII
34
transition by Haas et al. of
.
We
discuss
the interpretation of this in the framework of current shock and
PDR models.