ALMA: Baby Star Spits a "Spinning Jet"
Posted: Mon Jun 12, 2017 9:48 pm
Baby Star Spits a “Spinning Jet” As It Munches Down on a “Space Hamburger”
ALMA | ESO | NRAO | NAOJ | 2017 Jun 12
A Rotating Protostellar Jet Launched from the Innermost Disk of HH 212 - Chin-Fei Lee et al
http://asterisk.apod.com/viewtopic.php?p=270803#p270803
ALMA | ESO | NRAO | NAOJ | 2017 Jun 12
[img3="Jet and disk in the HH 212 protostellar system: (a) Molecular jet (green image) ejected from the innermost part of the accretion disk (orange image), observed with ALMA at a resolution of 8 au. A dark lane is seen in the disk equator, causing the disk to appear as a “hamburger”. A size scale of our solar system is shown in the lower right corner for size comparison. (b) Split of the redshifted (turning away from us) and blueshifted (turning toward us) emission of the jet in order to show the spinning motion of the jet, as indicated by the green arrows. Blue and red arrows show the rotation of the disk, which has a direction the same as the jet rotation.Protostellar jets are seen coming out from protostars (baby stars), representing one of the most intriguing signposts of star formation. An international research team, led by Chin-Fei Lee in Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan), has made a new breakthrough observation with the Atacama Large Millimeter/submillimeter Array (ALMA), finding a protostellar jet to be spinning, convincingly for the first time. This new result confirms the expected role of the jet in removing the excess angular momentum from the innermost region of an accretion disk (space hamburger), providing a solution to the long-standing problem of how the inner accretion disk can feed a protostar.
Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al"]http://www.almaobservatory.org/wp-conte ... 2a-lee.jpg[/img3][hr][/hr]
“We see jets coming out from most of baby stars, like a train of bullets speeding down along the rotational axis of the accretion disks. We always wonder what their role is. Are they spinning, as expected in current models of jet launching? However, since the jets are very narrow and their spinning motion is very small, we had not been able to confirm their spinning motion. Now using the ALMA with its unprecedented combination of spatial and velocity resolutions, we not only resolve a jet near a protostar down to 10 astronomical units (au) but also detect its spinning motion”, says Chin-Fei Lee at ASIAA. “It looks like a baby star spits a spinning bullet each time it takes a bite of a space hamburger.” ...
HH 212 is a nearby protostellar system in Orion at about 1300 lightyears. The central protostar is very young with an age of only 40,000 years (which is about 10 millionth of the age of the Sun) and a mass of only a fifth of the Sun. Recent ALMA observations at submillimeter wavelength have detected an accretion disk feeding the central protostar. The disk is nearly edge-on and has a radius of about 60 au. Interestingly, it shows a prominent equatorial dark lane sandwiched between two brighter features, appearing as a “space hamburger”. ...
A Rotating Protostellar Jet Launched from the Innermost Disk of HH 212 - Chin-Fei Lee et al
- Nature Astronomy 1:0152 (12 Jun 2017) DOI: 10.1038/s41550-017-0152
http://asterisk.apod.com/viewtopic.php?p=270803#p270803