National Astronomical Observatory of Japan | ALMA | 2017 Feb 08
Using observations of molecules in the protostar L1527 taken by the ALMA observatory in northern Chile, a group of researchers have uncovered new clues to understanding how dust in a collapsing molecular cloud can shed angular momentum and penetrate beyond an area known as the “centrifugal barrier” to find its way to the surface of the forming star.
[img3="Artist's impression of L1527 -- Credit: RIKEN"]http://www.almaobservatory.org/images/n ... _small.jpg[/img3][hr][/hr]One of the big puzzles in astrophysics is how stars like the Sun manage to form from collapsing molecular clouds in star-forming regions of the universe. The puzzle is known technically as the angular momentum problem in stellar formation. The problem essentially is that the gas in the star-forming cloud have some rotation, which gives each element of the gas an amount of angular momentum. As they collapse inward, eventually they reach a state where the gravitational pull of the nascent star is balanced by the centrifugal force, so that they will no longer collapse inward of a certain radius unless they can shed some of the angular momentum. This point is known as the centrifugal barrier.
Now, using measurements taken by radio antennas, a group led by Nami Sakai of the RIKEN Star and Planet Formation Laboratory has found clues as to how the gas in the cloud can find their way to the forming star. To gain a better understanding of the process, Sakai and her group turned to the ALMA observatory, a network of 66 radio dishes located high in the Atacama Desert of northern Chile. The dishes are connected together in a carefully choreographed configuration so that they can provide images on radio emissions from protostellar regions around the sky.
The group chose to observe a protostar designated as L1527, located in a nearby star-forming region known as the Taurus Molecular Cloud. The protostar, located about 450 light-years away, has a spinning protoplanetary disk, almost edge-on to our view, embedded in a large envelope of molecules and dust. ...
Vertical Structure of the Transition Zone from Infalling Rotating Envelope
to Disk in the Class 0 Protostar, IRAS 04368+2557 - Nami Sakai et al (preprint)