Abstract
In the present talk I will show our recent results of submillimeter continuum and molecular-line observations of prototypical protostellar binary systems L1551 IRS 5 and L1551 NE observed with the SMA. In both sources we found ~500-AU scale “circumbinary disks” surrounding the protostellar binary systems, elongated perpendicularly to the axis of the associated protostellar jets. The circumbinary disk around L1551 NE shows a clear Keplerian rotation with a central stellar mass ~0.8 M. On the other hand, the circumbinary disk around L1551 IRS 5 does not show a Keplerian rotation but shows vrot ~r-1 rotation. In L1551 IRS 5, the expected radius of the Keplerian rotation is ~35 AU, which is comparable to the orbital radius of the binary. This mean that in L1551 IRS 5 there is no Keplerian circumbinary disk. I will discuss the different rotational profiles of the circumbinary disks around the prototypical binary protostars in the context of binary formation and evolution.
Coffee and tea will be served 20 minutes prior to the seminar.