A Molecular Outflow Traced by SIO Masers in Orion KL

Citation:

Sheperd S. Doeleman, Colin J. Lonsdale, and Shannon Pelkey. 1999. “A Molecular Outflow Traced by SIO Masers in Orion KL.” The Astrophysical Journal Letters, 510, Pp. L55-L58.

Abstract:

We present full-resolution (~0.2 mas, ~0.1 AU) Very Long BaselineInterferometry maps of the v=1, J=1-->0 SiO masers in the Orion KLnebula. The morphology and turbulent nature of the maser emission arguesagainst models in which the masers form in an expanding and rotatingprotostellar disk. Rather, we find that the symmetry evident in the SiOmaser emission points toward its genesis in a bipolar outflow. Watermasers that also appear toward Orion KL are known to share the velocityprofile and double-peaked characteristics of the SiO maser emission yetform much farther away from the protostar. We link the water masers toour present results by proposing that both species of maser form arounda flared molecular outflow of roughly constant velocity.