Protostellar Disk Fragmentation


1.3 mm continuum emission of protostellar disk Serpens-FIRS1 showing multiple fragments including a pair of binary.

As a result of gravitational contraction, the cloud shrinks in size and the rotation of the cloud increases to conserve angular momentum of the system. Protostellar disks are produced as its direct consequence, and are expected to be ubiquitous in recently formed stars. The study of the formation and evolution of protostellar disks is vital for understanding both star and planet formation. These disks are predicted to form early in the protostellar stage by both analytic models and simulations. If disks form early when the protostar is still embedded in a thick layer of dust and gas, they can accrete material from the infalling core until they become gravitationally unstable and fragment. These fragments can fall into the central star, causing short bursts of accretion, or produce massive exoplanets and even form a stellar or planetary companion around the central star. We report discovery of the first ever detection of such a fragmenting disk around an intermediate mass Class 0 (recently formed) protostar called Serpens-FIRS1 in Aquila region. While the work is still in progress, we find a striking similarity when we compare the simulation of equivalent mass fragmenting disk with our data. This shows that the observed fragmentation in Serpens-FIRS1 protostar can be explained by a model of a protostellar disk that is fragmenting due to gravitational instability.