Vol. 551
In section 6. Interstellar and circumstellar matter

The standard model of low-mass star formation applied to massive stars: a multi-wavelength picture of AFGL 2591

by K. G. Johnston, D. S. Shepherd, T. P. Robitaille, and K. Wood, A&A 551, A43


The authors present VLA 3.6 cm and 7 mm, as well as Combined Array for Research in Millimeter Astronomy C18O and 3 mm, continuum observations and investigate the morphology and kinematics of the ionized gas, dust, and molecular gas around AFGL 2591. The observed 3.6 cm images uncover for the first time that the central powering source AFGL 2591-VLA3 has a compact core and collimated jet morphology, extending 4000 AU eastward from the central source with an opening angle of <10 degrees. However, at 7 mm VLA3 does not show a jet morphology, but instead compact (<500 AU) emission, some of which is estimated to be from dust emission. The spectral index of AFGL 2591-VLA 3 between 3.6 cm and 7 mm is similar to the index of an ionized wind. The C18O emission uncovers dense entrained material in the outflow(s) from these young stars. The main features of the SED and 2MASS images of AFGL 2591-VLA3 are also reproduced by the dust geometry in their model of a rotationally flattened envelope with and without a disk. These results are consistent with a picture of massive star formation similar to what is seen for low-mass protostars. However, within its envelope, AFGL 2591-VLA3 contains at least four other young stars, constituting a small cluster. Therefore it appears that AFGL 2591-VLA3 may be able to get its accreting material from a shared gas reservoir, while still exhibiting the phenomena expected during the formation of low-mass stars.