Outflow forces in intermediate mass star formation
  Intermediate mass protostarsprovide a bridge between theories of low- and
high-mass star formation. Emerging molecular outflows can be used to determine
the influence of fragmentation and multiplicity on protostellar evolution
through the correlation of outflow forces of intermediate mass protostars with
the luminosity. The aim of this paper is to derive outflow forces from outflows
of six intermediate mass protostellar regions and validate the apparent
correlation between total luminosity and outflow force seen in earlier work, as
well as remove uncertainties caused by different methodology. By comparing CO
6--5 observations obtained with APEX with non-LTE radiative transfer model
predictions, optical depths, temperatures, densities of the gas of the
molecular outflows are derived. Outflow forces, dynamical timescales and
kinetic luminosities are subsequently calculated. Outflow parameters, including
the forces, were derived for all sources. Temperatures in excess of 50 K were
found for all flows, in line with recent low-mass results. However, comparison
with other studies could not corroborate conclusions from earlier work on
intermediate mass protostars which hypothesized that fragmentation enhances
outflow forces in clustered intermediate mass star formation. Any enhancement
in comparison with the classical relation between outflow force and luminosity
can be attributed the use of a higher excitation line and improvement in
methods; They are in line with results from low-mass protostars using similar
techniques. The role of fragmentation on outflows is an important ingredient to
understand clustered star formation and the link between low and high-mass star
formation. However, detailed information on spatial scales of a few 100 AU,
covering all individual members is needed to make the necessary progress.
