Invited Presentation

ALMA Observations from Protostellar Disks to Earlier-Phase Objects

Author(s): Yusuke Aso (Univ. of Tokyo), N. Ohashi, K. Saigo, M. Saito, K. Tomisaka (NAOJ), Y. Aikawa (Univ. of Tsukuba), M. Machida (Kyushu Univ.), S. Takakuwa (Kagoshima Univ.), K. Tomida (Osaka Univ.), J. Williams (Univ. of Hawaii), and H.-W. Yen (ESO)

Presenter: Yusuke Aso (The University of Tokyo)

In recent studies, Keplerian disks have been identified not only around T-Tauri stars but also around protostars by investigating velocity structures in detail. Such protostellar disks would be related with origins of planet formation or remarkable features seen in T-Tauri disks. Although protostellar disks differ from T-Tauri disks that they are embedded in protostellar envelopes and mass is still accreting from the envelopes onto the disks, it is still not understood well whether or not these differences affect on structures of protostellar disks. In order to reveal structures of protostellar disks, we have observed the Class 0/I protostar L1527 IRS (d=140 pc) with ALMA Cycle 1 in C18O (J=2-1) and 1.3-mm continuum emission. The size of the Keplerian disk around L1527 IRS was estimated to be ~74 AU based on the C18O results. Continuum visibility shows clearly different profiles in the major- and minor axes of the disk. Our model fitting to the continuum visibility suggests a density jump between the disk and the surrounding envelope, and also that the disk around L1527 IRS has similar structures to T-Tauri disks. We will also report results of our studies in Serpens Main cluster (d=429 pc) using ALMA Cycle 3 (PI: Y. Aso); we found a remarkable 1.3-mm continuum source with Tbol=23 K, Lbol=0.05 Lo, and a bipolar 12CO outflow whose dynamical time is ~600 yr, suggesting that the source is in a very early phase of star formation.