Oral Presentation

The Co-evolution of Disks and Stars in Embedded Stages

Author(s): Yuki Okoda, Yoko Oya, Satoshi Yamamoto

Presenter: Yuki Okoda (The University of Tokyo)

IRAS 15398−3359 is the low-mass Class 0 protostellar source located in the Lupus 1 molecular cloud at a distance of 155 pc. We have observed this source in the SO emission which has a compact distribution around the protostar within 40 au in radius. The velocity structure of the SO emission indicates a rotating disk around the protostar. We estimate the protostellar mass to be 0.007 solar mass assuming the Keplerian motion. Since this source is deeply embedded in the envelope, such a low mass means the youth of the protostar. This result suggests that the disk structure can be formed in the earlier stage in star formation than ever expected.
We have also analyzed the ALMA archival data of the C18O, SO, and 13CO emission for L328-IRS, IRAM 04191-IRS, and Chamaeleon-MMS 1, respectively. They seem to accompany the disk structures. We plot the relation between the protostellar masses and the disk masses of the above four sources as well as 16 young protostellar sources reported in previous works. The result implies co-evolution of disks and protostars from the youngest stage.