ASIAA: Youngest Accretion Disk Detected in Star Formation
Posted: Tue Sep 04, 2018 6:44 pm
Youngest Accretion Disk Detected in Star Formation
Academia Sinica Institute of Astronomy and Astrophysics | 2018 Sep 04
ALMA Observations of the Very Young Class 0 Protostellar System
HH211-mms: A 30 au Dusty Disk with a Disk Wind Traced by SO? ~ Chin-Fei Lee et al
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Academia Sinica Institute of Astronomy and Astrophysics | 2018 Sep 04
In Support of an “Early-Start, Slow-Growth” Scenario for Accretion Disk Formation
An international team led by Chin-Fei Lee at the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) has discovered a very small accretion disk formed around one of the youngest protostars, with the Atacama Large Millimeter/submillimeter Array (ALMA). This discovery poses a constraint on current theory of disk formation stronger than before, by pushing the disk formation time by a factor of a few earlier. Moreover, a compact rotating outflow has been detected. It may trace a disk wind carrying away angular momentum from the disk and thus facilitate the disk formation.Disk and outflow in the HH 211 protostellar system. A zoom-in to the innermost region
around the central protostar, showing the disk and outflow there. Asterisk marks the
possible position of the central protostar. Gray arrows show the jet axis. Orange image
shows the dusty disk at submillimeter wavelength obtained with ALMA. Blue and red
images show the blueshifted and redshifted parts of the outflow coming out from the
disk rotating around the jet axis. Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al
“ALMA is so powerful that it can resolve an accretion disk with a radius as small as 15 astronomical units (AU),” says Chin-Fei Lee at ASIAA. “Since this disk is about a few times younger than the previously resolved youngest disk, our result has provided a stronger constraint on current theory of disk formation by pushing the disk formation time by a factor of a few earlier. Moreover, together with the previous results of the older disks, our disk result favors a model where the disk radius grows linearly with the protostellar mass, and thus supporting the ‘early-start, slow-growth’ scenario against the ‘slow-start, rapid-growth’ scenario for accretion disk formation around protostars.”
HH 211 is one of the youngest protostellar systems in Perseus at a distance of about 770 light-years. The central protostar has an age of only about 10,000 years (which is about 2 millionths of the age of our Sun) and a mass of less than 0.05 solar mass. It drives a powerful bipolar jet and thus must accrete material efficiently. ...
ALMA Observations of the Very Young Class 0 Protostellar System
HH211-mms: A 30 au Dusty Disk with a Disk Wind Traced by SO? ~ Chin-Fei Lee et al
- Astrophysical Journal 863(1):94 (2018 Aug 10) DOI: 10.3847/1538-4357/aad2da
arXiv.org > astro-ph > arXiv:1807.05336 > 14 Jul 2018
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