Astron. Astrophys. 345, 949-964 (1999)
The main goal of this paper was to allow a better analysis of the
disk-outflow system studied by CFTWO, using the high angular
resolution (0:007) capability of the PdBI at 1.3 mm. This aim has
been completely accomplished. In particular the following results have
The observations in the CH3CN(12-11) lines confirm the
existence of a rotating disk at the nominal position of
IRAS 20126+4104. Such a disk probably extends over a much larger
region than that traced by CH3CN, as suggested by maps in
the H13CO+(1-0) line.
Along the axis of the disk a bipolar jet is seen in the SiO(2-1)
line. Such a jet is in very good agreement with the H2 line
image at 2.122 µm (CFTWO; 1998) and seems to feed
the bipolar outflow mapped by CFTWO in the HCO+(1-0) line.
The jet axis turns out to lie almost in the plane of the sky.
The IRAS source is embedded in a hot core of
1500 AU, traced by the
CH3CN lines as well as by the continuum emission from
10 µm to 3 mm. In particular, the 10 and
20 µm emission - unlike that in near-infrared (see
CFTWO) - is probably due to thermal emission arising from the core and
from a small "tail" tracing the inner part of the jet seen in the SiO
and H2 lines.
A study of the CH3CN(12-11) lines indicates that the
disk is Keplerian and probably collapsing towards a central object
It is also possible to estimate the mass accretion rate from the
collapse velocity and continuum emission at 1.3 mm.
Since the observed luminosity of IRAS 20126+4104
much less than expected for a
24 ZAMS star, we conclude that
if a single object is responsible for the Keplerian rotation, then
this must be a massive protostar . The estimated accretion
luminosity () is indeed consistent
with the measured one.
We conclude that IRAS 20126+4104 could represent the first example
of a high-mass protostar complete with Keplerian accretion disk and
© European Southern Observatory (ESO) 1999
Online publication: April 28, 1999