(We will rebroadcast this in STB-210 conference room, please join us today!) COLLOQUIUM WEDNESDAY, September 11, 2013 IfA-Manoa Auditorium—3:30pm JOHN TOBIN NRAO The Initial Phases of Solar System and Binary Star Formation The formation of proto-planetary disks begins during the earliest phase of the starformation process, while the nascent protostar is still surrounded by a dense envelope of gas and dust. Using sub/millimeter interferometry, we can probe through the dense envelope revealing the the protostellar disk. However, the properties of disks early in the protostellar phase are still quite uncertain as there are currently only a few clear examples. Understanding the early disks are important given that they set the initial conditions for planet formation and may play a role in binary star formation through fragmentation via gravitational instability. Moreover, the rotation curve of these protostellar disks reveal the masses of the protostars, an important parameter that has lacked observational constraint until recently. Probing deeper, we also find binaries in a few protostellar systems that with ~100 AU separations, a strong indication that the disks themselves are fragmenting early-on. But statistics are not yet good enough to know how binaries tend to form, whether through disk fragmentation or migration. Our ability to detect disks and binaries early in the protostellar phase has progressed to the point where a broad characterization is needed, necessitating a large survey that we are beginning to conduct with the VLA this fall toward all known protostars in the Perseus cloud. Moreover, the sensitivity of ALMA will make observations of disk kinematics routine toward protostars enabling masses of a large number of Class 0 protostars to be measured for the first time. Here are instructions from Pui Hin, when you call the conference center: "I am asking people to connect 15 minutes in advance so that we have time to help solve any problem if needed. From any Polycom or compatible end-point, call 128.171.226.130##2001. If for some reason, a connection is not established, then first call 128.171.226.130. Once connected, press the # key. The numeric keypad will appear on the screen. Complete the call by pressing 2001 followed by the # key on your handset. Please connect at least 15 minutes in advance." People at remote sites please mute your mic’s during colloquium.
Posted on: Wed, 11 Sep 2013 22:16:30 +0000