Anatomy of a high-mass star forming cloud:
the G24.78+0.08 (proto)stell ar cluster
by
R. Cesaroni, C. Codella, R.S. Furuya, L. Testi
Abstract:
We present the results of an interferometric and single-dish study of
G24.78+0.08, a region associated with high-mass star formation. Observations
have been carried out in several molecular species, which are suitable to
trace environments with different densities and temperatures. Evidence for
this region to contain a cluster of very young massive stellar objects has
been presented in a previous paper (Furuya et al. 2001). We suggest
that the embedded stars might be too young to have affected the surrounding
molecular cloud significantly on a large scale. This gives us the opportunity
to investigate the configuration of the cloud as it was prior to the star
formation episode. We assess that the (proto)stellar cluster lies at the
center of a molecular clump with diameter of ~2 pc: to a good
approximation this may be described as a spherically symmetric clump with
density profile of the type n~R^(-1.8). Inside 0.5 pc from
the center, instead, the gas is much more inhomogeneous and concentrated in a
few high-density cores surrounding the (proto)stars. Our findings indicate
that a self-regulating formation mechanism for the high-mass stars in G24.78
is plausible: in the proposed scenario star formation would occur from
inside-out collapse of the parsec-scale clump, followed by infall reversal
due to outflows powered by the newly formed massive stars. We also find that
one of the two bipolar outflows powered by the embedded YSOs is more extended
and hence older than the other, thus confirming the evolutionary sequence
proposed in our previous article.
Mantained by:
Leonardo Testi