The following document lists the file abstract/SMOLINAR_HII_PREC.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
Since the beginning of star formation research the main aim has been
to find the youngest forming star, thus providing the link between
gas condensations and visible stars. Yet when looking at observational
evidence exhibited by proposed candidates, nature presents us with
such a variety of observational phenomena that one can seldom
account for all of them.
With this proposal we want to address the problem of finding the
youngest high mass forming stars and, by comparison with other well
studied classes of Young Stellar Objects (YSOs), to understand the
evolution of the physical conditions of circumstellar matter around
massive stars since before the ignition of hydrogen burning.
Our proposed targets are luminous IRAS sources believed to be in
a phase preceeding the appearance of ultracompact (UC) HII regions;
we will use LWS in grating mode to observe the emitted spectrum and
compare with that of known UC HII regions (in which hydrogen burning
has obviously started) as well as with theoretical predictions of
line intensities from photoionization regions.
All of our proposed sources are deeply embedded within their dust
cocoons and to investigate the physical conditions nearest to the
central forming objects makes the use of ISO mandatory.