High-resolution studies of young molecular outflow sources

Gerd Weigelt, Thomas Preibisch, Dieter Schertl, Yuri Y. Balega, Michael D. Smith

European Southern Observatory Workshop on: The Origins of Stars and Planets: The VLT View

ESO Astrophysics Symposia, XXVII (2002)


The VLT/VLTI will allow the observation of young molecular outflows (e.g. R Mon or Mon R2) with unprecedented angular resolution. One of our goals is the study of the inner region of outflows and the interaction of the outflows with the circumstellar material. We may then be able to explain how the outflows were generated and how they have evolved. This will significantly contribute to the understanding of the phenomenon of protostellar outflows. As an example, we present K'-band bispectrum speckle interferometry images of the the deeply embedded young stellar object S140 IRS 1. Diffraction-limited resolution of 76 mas (~ 70 AU) and a dynamical range of more than 8 magnitudes were achieved with the SAO 6 m telescope. Our image of S140 reveals a wealth of previously unseen complex structures. In addition to a very clumpy feature pointing from the central source to the south-east, we find several arc-like structures north-east of IRS 1 and extended diffuse emission south of IRS 1. The diffuse structures around IRS 1 seem to trace the interaction of energetic outflows from IRS 1 with the circumstellar material. In combination with molecular line emission maps from the literature, our image provides evidence for the presence of two distinct bipolar outflow systems. A system of three arc-like structures north-east of IRS 1 suggests directional variability of the outflow, perhaps caused by the precession of a jet- or wind-driven outflow. We discuss the implications for the nature of the central source.

For more detailed information see our A&A paper.

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