Kazuhito Motogi (Hokkaido University)

A Time-resolved Study of High Mass Protostellar Jets and Accretion Disks. - Kazuhito Motogi Colloquium

ATNF Marsfield Lecture Theatre

Abstract

Recent studies indicate that high mass star formation can be achieved by the disk accretion mechanism.
Quantitative evolution of a high mass protostar is determined by detailed accretion properties and protostellar feedbacks in this case.
One of the important clues of accretion properties onto the protostellar surface is a high mass protostellar (HMP) jet,
which is thought to be launched from the innermost disk region.

HMP jet is well known as highly variable phenomenon.
Its launching interval reaches an order of one year or less.
Such an intermittent launching process can be related to time-dependent variations at the launching point.
There are two possible causes of it; (1) Significant variation of an accretion rate,
(2) Recurrent amplification and relaxation of magnetic pressure along the MHD launching process.
In order to test these possibilities, time-resolved study of HMP jet and disk is essential.
On the other hand, our recent study suggests that some peculiar 22 GHz water maser sources can be an excellent tracer of time variability of HMP jet.

In this talk, I introduce you our VLBI & single dish study of the high mass protostellar object G353.27+0.641, and discuss about a future plan of highly time-resolved observations of high mass disk – jet systems with ALMA, using a 22 GHz water maser emission.