Oral Presentation

Are graviational instabilities and accretion outbursts common for low-mass protostellar disks?

Author(s): Hiro Takami et al.

Presenter: Hiro Takami (ASIAA)

It is suggested that steady mass accretion observed for many low-mass protostars an young stars can explain only a small fraction of their final masses. This problem can be overcome if each protostar experiences accretion outbursts like those observed for some stars (FUors, EXors). We can explain the fact that many protostars and young stars do not show such outbursts simply if the periods of accretion outbursts are significantly smaller than the time scale of star formation, and therefore the chances of the observations are quite low. The mechanisms to trigger the accretion outbursts have been debated over many years.
In my talk I will first summarize our studies with Subaru HiCIAO and numerical simulations, which support gravitational instabilities in disks as the triggering mechanism of the FUor outburts. I will then present our recent ALMA observations of the FUor V900 Mon, which support the idea that many protostars experiences FUor outbursts. Throughout, these results support the idea that gravitational instabilities in disks occur for many protostars.