The JCMT Newsletter Number 10
 RAS Discussion meeting Abstract
SCUBA and Star Formation
ABSTRACT
The understanding of low-mass star formation has made significant progress in
recent years. Spectroscopic observations have detected infall in Class 0
protostars. Much current interest centres around the pre-stellar stage, which
is defined as the phase in which a gravitationally bound core has formed in a
molecular cloud, but no central hydrostatic protostar exists yet within the
core. The significance of pre-stellar cores is that they constrain the initial
conditions of protostellar collapse. We have previously shown that some
pre-stellar cores have flat inner radial density profiles, and showed that this
may be consistent with a mechanism for magnetic support, with evolution by
ambipolar diffusion.
We have studied 44 of the starless cores from the list of Myers' ammonia cores
and found 850-micron SCUBA detections of roughly half of them. Our study sample
appears complete down to a central nunmber density level of 10(4)/cm(3), while
our detections seem to correspond to densities above 10(5)/cm(3). At this level
we appear to detect more cores with SCUBA than would be predicted by simple
ambipolar diffusion models. Hence one of the assumptions of the models may have
to be revised, such as departure from cylindrical symmetry. Alternatively it is
possible that significant turbulent velocity fields within the pre-stellar
cores may be preventing collapse.
Derek Ward-Thompson, ROE
Last Modification Date 1998/03/2 - Last Modification Author: gdw
Graeme Watt (gdw)
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