ASIAA: Spiral Arms Finally Seen in Accretion Disk Around a Baby Star

[bystander]

Spiral Arms Finally Seen in Accretion Disk Around a Baby Star
Academia Sinica Institute of Astronomy and Astrophysics | 2019 Oct 17

Accretion disk in the HH 111 protostellar system detected with ALMA in dust continuum emission at 850 micron. Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al

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An international research team, led by Chin-Fei Lee, ... has detected a pair of spiral arms in an accretion disk around a protostar (baby star), using the ALMA. Interestingly, these spiral density enhancements make the disk appear like a “space whirlpool.” The finding not only supports current theories of accretion disk feeding process, but also potentially brings key insights into the processes of grain growth and settling that are important to planet formation.

“Thanks to the powerful ALMA, we finally detected a pair of spirals in a young accretion disk around a baby star. These spirals are long predicted in theory. They play a crucial role in the transport of angular momentum within the disk, allowing disk material to swirl towards the baby star”, says Chin-Fei Lee at ASIAA with excitement. “Our detection of the spirals is an important milestone in understanding the feeding process of baby stars.”

Spirals detected in protoplanetary disks around somewhat older stars seem to be produced by interaction with unseen baby planets. Unlike those, the spirals here are induced by accretion of material from the surrounding molecular cloud onto the disk. ...

Feeding a Baby Star Through a Whirlpool in Space
ALMA (ESO/NAOJ/NRAO) | 2019 Oct 14

Spiral Structures in an Embedded Protostellar Disk Driven
by Envelope Accretion ~ Chin-Fei Lee, Zhi-Yun Li, Neal J. Turner

• Nature Astronomy (online 14 Oct 2019) DOI: 10.1038/s41550-019-0905-x
• arXiv.org > astro-ph > arXiv:1909.02812 > 06 Sep 2019

[Ann]

Academia Sinica Institute of Astronomy and Astrophysics wrote:

The protostar with its disk lies at the center of HH 111, a pair of supersonic jets emerging from a molecular cloud core located 1300 lightyears away in the constellation Orion. The protostar is about half a million years old, just one ten-thousandth the age of our Sun, and has a mass 50% greater than our Sun.

So HH 111 is going to be an F-type main sequence star, then!

Ann