Exploring the 100 au Scale Structure of the Protobinary System NGC 2264 CMM3 with ALMA

Yoshiki Shibayama, Yoshimasa Watanabe, Yoko Oya, Nami Sakai, Ana López-Sepulcre, Sheng Yuan Liu, Yu Nung Su, Yichen Zhang, Takeshi Sakai, Tomoya Hirota, Satoshi Yamamoto

研究成果査読

抄録

We have observed the young protostellar system NGC 2264 CMM3 in the 1.3 mm and 2.0 mm bands at a resolution of about 0.″1 (70 au) with ALMA. The structures of two distinct components, CMM3A and CMM3B, are resolved in the continuum images of both bands. CMM3A has an elliptical structure extending along the direction almost perpendicular to the known outflow, while CMM3B reveals a round shape. We have fitted two 2D Gaussian components to the elliptical structure of CMM3A and CMM3B and have separated the disk and envelope components for each source. The spectral index α between 2.0 and 0.8 mm is derived to be 2.4-2.7 and 2.4-2.6 for CMM3A and CMM3B, respectively, indicating optically thick dust emission and/or grain growth. A velocity gradient in the disk/envelope direction is detected for CMM3A in the CH3CN, CH3OH, and 13CH3OH lines detected in the 1.3 mm band, which can be interpreted as the rotation of the disk/envelope system. From this result, the protostellar mass of CMM3A is roughly evaluated to be 0.1-0.5 M o˙ by assuming Keplerian rotation. The mass accretion rate is thus estimated to be 5 10-5 - 4 10-3 M o˙ yr-1, which is higher than the typical mass accretion rate of low-mass protostars. The OCS emission line shows a velocity gradient in both outflow direction and disk/envelope direction. A hint of outflow rotation is found, and the specific angular momentum of the outflow is estimated to be comparable to that of the disk. These results provide us with novel information on the initial stage of a binary/multiple system.

本文言語English
論文番号32
ジャーナルAstrophysical Journal
918
1
DOI
出版ステータスPublished - 2021 9 1

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学

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