RG Research: Protostellar Outflows

When dense cores in molecular clouds collapse, any small rotation is amplified by conservation of angular momentum, which leads to the formation of an accretion disk. The star/disk system drives a powerful bipolar outflow that simultaneously removes angular momentum to allow the protostar to grow, and starts to clear away the surrounding core material. Current models invoke magnetohydrodynamic processes to tap the gravitational potential of the star/disk system to power the bipolar outflow. Our knowledge of outflows has improved, in part due to observations from the Submillimeter Array that probes the highly excited molecular lines in the sub-millimeter wavelengths.


Tyler Bourke, Paul Ho, Eric Keto, Hau-Yu Baobab Lu, T. K. Sridharan, Ke Wang, Qizhou Zhang, Lei Zhu, Izaskun M. Jimenez-Serra

  bipolar outflow image

Herbig-Haro (HH) 211 is a bipolar outflow located at 1000 light-years away in the constellation Perseus. Sitting at the center of the system is a young protostar that powers the protostellar outflow. The protostar is about 20,000 years old with a mass of only six percent of the mass of our Sun. It will eventually grow into a star like our Sun in tens of millions of years. The color scales are the near infrared H2 emissions. Blue and red contours are the blue- and red-shifted outflow in the SiO 8-7 emission. The green contours mark the dust emission at 870 micron surrounging the protostar (Image credit: Qizhou Zhang. Reference: Lee et al. 2007).


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