University of Wales, Cardiff, UK
Results are outlined of an ISOPHOT study of pre-stellar cores.
The pre-stellar phase is one in which a dense core in a molecular
cloud is gravitationally bound, but contains no embedded luminosity
source. This takes place prior to the protostellar Class 0 phase, and
is believed to represent the initial conditions for protostellar collapse.
For the first time these cores, which were not detected by IRAS, have
been detected in the infra-red at 200 and 170
m, but not at 90m.
The similarity in apparent morphology between the 200 & 170m maps
and the submillimetre data from SCUBA shows that we are detecting
the same dust in the far-ir as in the submm. The lack of detections at
90m shows that there is no significant quantity of warm dust in
these sources, and a single temperature modified black-body can fit the
data in each case, allowing the submillimetre data to be converted into
more accurate mass estimates. Likewise, source luminosities can be
measured, where previously we could only estimate upper limits. This
study therefore represents one of the most detailed observational studies
so far carried out of the initial conditions of star formation, and allows
us to compare real data with the exact predictions of the different models.