Outflows from Massive Protostars

Bipolar Outflows associated with High-Mass Young Stars are spectacular structures in the near infrared: massive eruptions of molecules accompany the star formation process. Michael Smith has been investigating.............

OMC-1: we have found the distribution in the ortho-para ratio of molecular hydrogen, after imaging the outflow in several K-band lines. These are the first ever such 'ratio maps'. First, here is our 1-0 S(1) image, which displays the famous 'bullets':

The Orion Bullets and bows are detected; here are the ortho-para images of the Northern lobe and bullets:

We see here the ortho-para ratio in three ranges: Left: 0.3 < o/p < 5.3; centre: 1.3 < o/p < 4.3; right: 2.3 < o/p < 3.3. Resolution: 1.04 arcsec. Although the ratio appears to vary here, it is mainly an effect of the high noise level in the weak 1-0 S(0) and S(2) lines. We show that the o/p ratio is constant, around 3.0, in the regions where the line fluxes can be accurately detected.

Other outflows which could be included on this page are Cepheus A, W 75N and DR21. DR21 has a more conical, turbulenct form (from work with Chris Davis):

Last Revised: 2009 November 6th