%0 Generic %1 motogi2019first %A Motogi, Kazuhito %A Hirota, Tomoya %A Machida, Masahiro N. %A Yonekura, Yoshinori %A Honma, Mareki %A Takakuwa, Shigehisa %A Matsushita, Satoki %D 2019 %K ALMA Disk Toomre-factor %R 10.38747/2041-8213/ab212f %T The first bird's-eye view of a gravitationally unstable accretion disk in high-mass star formation %U http://arxiv.org/abs/1905.12983 %X We report on the first bird's-eye view of the innermost accretion disk around the high-mass protostellar object G353.273+0.641, taken by Atacama Large Millimter/submillimeter Array long-baselines. The disk traced by dust continuum emission has a radius of 250 au, surrounded by the infalling rotating envelope traced by thermal CH$_3$OH lines. This disk radius is consistent with the centrifugal radius estimated from the specific angular momentum in the envelope. The lower-limit envelope mass is $\sim$5-7 M$_ødot$ and accretion rate onto the stellar surface is 3 $\times$ 10$^-3$ M$_ødot$ yr$^-1$ or higher. The expected stellar age is well younger than 10$^4$ yr, indicating that the host object is one of the youngest high-mass objects at present. The disk mass is 2-7 M$_ødot$, depending on the dust opacity index. The estimated Toomre's $Q$ parameter is typically 1-2 and can reach 0.4 at the minimum. These $Q$ values clearly satisfy the classical criteria for the gravitational instability, and are consistent with the recent numerical studies. Observed asymmetric and clumpy structures could trace a spiral arm and/or disk fragmentation. We found that 70$\%$ of the angular momentum in the accretion flow could be removed via the gravitational torque in the disk. Our study has indicated that the dynamical nature of a self-gravitating disk could dominate the early phase of high-mass star formation. This is remarkably consistent with the early evolutionary scenario of a low-mass protostar.

@misc{motogi2019first, abstract = {We report on the first bird's-eye view of the innermost accretion disk around the high-mass protostellar object G353.273+0.641, taken by Atacama Large Millimter/submillimeter Array long-baselines. The disk traced by dust continuum emission has a radius of 250 au, surrounded by the infalling rotating envelope traced by thermal CH$_3$OH lines. This disk radius is consistent with the centrifugal radius estimated from the specific angular momentum in the envelope. The lower-limit envelope mass is $\sim$5-7 M$_{\odot}$ and accretion rate onto the stellar surface is 3 $\times$ 10$^{-3}$ M$_{\odot}$ yr$^{-1}$ or higher. The expected stellar age is well younger than 10$^{4}$ yr, indicating that the host object is one of the youngest high-mass objects at present. The disk mass is 2-7 M$_{\odot}$, depending on the dust opacity index. The estimated Toomre's $Q$ parameter is typically 1-2 and can reach 0.4 at the minimum. These $Q$ values clearly satisfy the classical criteria for the gravitational instability, and are consistent with the recent numerical studies. Observed asymmetric and clumpy structures could trace a spiral arm and/or disk fragmentation. We found that 70$\%$ of the angular momentum in the accretion flow could be removed via the gravitational torque in the disk. Our study has indicated that the dynamical nature of a self-gravitating disk could dominate the early phase of high-mass star formation. This is remarkably consistent with the early evolutionary scenario of a low-mass protostar.}, added-at = {2019-05-31T15:48:04.000+0200}, author = {Motogi, Kazuhito and Hirota, Tomoya and Machida, Masahiro N. and Yonekura, Yoshinori and Honma, Mareki and Takakuwa, Shigehisa and Matsushita, Satoki}, biburl = {https://www.bibsonomy.org/bibtex/2db3fed3d54fc78386e29cf8f5f0bd341/heh15}, description = {The first bird's-eye view of a gravitationally unstable accretion disk in high-mass star formation}, doi = {10.38747/2041-8213/ab212f}, interhash = {89a9d6c6b72485f0978e8488ae3ea2ef}, intrahash = {db3fed3d54fc78386e29cf8f5f0bd341}, keywords = {ALMA Disk Toomre-factor}, note = {cite arxiv:1905.12983Comment: Accepted to ApJL, 11 pages, 3 figures, 2 tables}, timestamp = {2019-05-31T15:48:04.000+0200}, title = {The first bird's-eye view of a gravitationally unstable accretion disk in high-mass star formation}, url = {http://arxiv.org/abs/1905.12983}, year = 2019 }