Curated by RSF Research Staff
ALMA hears birth cry of a massive baby star
Thousands of stars are birthing every moment, and although we study and follow their evolution in so much detail we still do not know how they are actually formed. The standard model posits that young stellar objects (YSOs) – protostars and pre-main sequence stars – form when the denser regions of molecular clouds collapse under their own gravity. The question is - how do these YSOs accrete sufficient matter to form into a stable and more massive star? There must be a transfer of angular momentum, which has been predicted to be driven by outflows and jets, however due to a lack of observational data a mechanism has yet to be put forward.
Now for the first time a team of Japanese led astronomers, using the Atacama Large Millimeter/Submillimeter Array (ALMA), have observed a clear signature of rotation in the bipolar outflow of the YSO candidate, Orion Source I. The team therefore suggest that this outflow rotation must be what drives the transfer of angular of momentum, allowing matter to be accreted by the YSO so that a stable and more massive star can be formed. What causes the outflow rotation is another question, and one that may be solved from a unified physics perspective. In any case, more data is required to shed light on the exact mechanism and as well further our understanding of YSOs and the initial stages of star formation.