"We have combined the zoom of CARMA with the wide-angle of NRO to simultaneously capture the details of individual forming stars and the overall shape and motions of the giant
molecular cloud."
HII regions typically form within large
molecular clouds, often in clusters (due to triggered star formation), and are therefore are also associated with significant amounts of dust grains.
Their intense light has been burning a hole in the dark fog of the Orion
Molecular Cloud for tens of thousands of years.
Your body and the bacteria that reside on your skin are giving off a
molecular cloud of human-specific odorants.
It's also the brightest portion of a giant
molecular cloud (GMC) located approximately 6,000 light-years away in the Sagittarius spiral arm.
Using the L1641
molecular cloud that is part of the Orion A complex, the team showed that the mass distributions of the forming stars, which will become the IMF of that stellar population, are similar yet distinct for stars forming in the field (outside of the filaments) and on the filaments, with the former peaking at smaller mass values than the latter.
Consequently, with such high densities and large thermal velocities, these HII regions often cause otherwise collapsing clouds to expand into the ambient ISM, tearing apart the larger gravitationally bound
molecular cloud.
A far more challenging target toward the northwest, the Taurus
Molecular Cloud 1 (TMC-1) can be found just north of the Hyades and extends westward past the California Nebula (NGC 1499) and the Pleiades (M45).