Evidence for Evolution of the Outflow Collimation in Very Young Stellar Objects
Abstract
We present Very Long Baseline Array proper-motion measurements of water masers toward two young stellar objects (YSOs) of the W75 N star-forming region. We find that these two objects are remarkable for having a similar spectral type, being separated by 0.7" (corresponding to 1400 AU), and sharing the same environment, but with a strikingly different outflow ejection geometry. One source has a collimated, jetlike outflow at a 2000 AU scale, while the other has a shell outflow at a 160 AU scale expanding in multiple directions with respect to a central compact radio continuum source. This result reveals that outflow collimation is not only a consequence of ambient conditions but is something intrinsic to the individual evolution of stars and brings to light the possibility of noncollimated outflows in the earliest stages of YSOs.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2003
- DOI:
- 10.1086/380750
- Bibcode:
- 2003ApJ...598L.115T
- Keywords:
-
- ISM: Individual: Alphanumeric: W75;
- ISM: Jets and Outflows;
- Masers;
- Stars: Formation