Protostar displays a strange geometry
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.
|Artist's impression of L1527 [Credit: RIKEN]|
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 its way to the surface of 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.
|Integrated intensity distribution of CCH, superposed on the 0.8 mm dust continuum map. The infalling |
rotating envelope traced by CCH is broadened inward of the radius of about 150 au
[Credit: Sakai et al. (RIKEN)]
This behavior accorded well with calculations the group had done using a purely ballistic model, where the particles behave like simple projectiles that do not need to be influenced by magnetic or other forces.
According to Sakai, "We plan to continue to use observations from the powerful ALMA array to further refine our understanding of the dynamics of stellar formation and fully explain how matter collapses onto the forming star. This work could also help us to better understand the evolution of our own solar system."
These observation results were published as Sakai et al. "Vertical Structure of the Transition Zone from Infalling Rotating Envelope to Disk in the Class 0 Protostar, IRAS04368+2557" in the Monthly Notices of the Royal Astronomical Society in February 2017.
Source: RIKEN [February 07, 2017]