ALMA hears birth cry of a massive baby star

June 12, 2017
The massive protostar is surrounded by a disk of gas and dust. The outflow is launched from the surface of the outer disk. Credit: ALMA (ESO/NAOJ/NRAO)

Stars form from gas and dust floating in interstellar space. But, astronomers do not yet fully understand how it is possible to form the massive stars seen in space. One key issue is gas rotation. The parent cloud rotates slowly in the initial stage and the rotation becomes faster as the cloud shrinks due to self-gravity. Stars formed in such a process should have very rapid rotation, but this is not the case. The stars observed in the Universe rotate more slowly.

How is the rotational momentum dissipated? One possible scenario involves that the gas emanating from baby stars. If the gas outflow rotates, it can carry rotational momentum away from the system. Astronomers have tried to detect the of the outflow to test this scenario and understand its launching mechanism. In a few cases signatures of rotation have been found, but it has been difficult to resolve clearly, especially around massive baby .

The team of astronomers led by Tomoya Hirota, an assistant professor at the National Astronomical Observatory of Japan (NAOJ) and SOKENDAI (the Graduate University for Advanced Studies) observed a massive baby star called Orion KL Source I in the famous Orion Nebula, located 1,400 light-years away from the Earth. The Orion Nebula is the closest massive-star forming region to Earth. Thanks to its close vicinity and ALMA's advanced capabilities, the team was able to reveal the nature of the outflow from Source I.

"We have clearly imaged the rotation of the outflow," said Hirota, the lead author of the research paper published in the journal Nature Astronomy. "In addition, the result gives us important insight into the launching mechanism of the outflow."

The massive protostar is located in the center and surrounded by a gas disk (red). A bipolar gas outflow is ejected from the protostar (blue). Credit: ALMA (ESO/NAOJ/NRAO), Hirota et al.

The new ALMA observations beautifully illustrate the rotation of the outflow. The outflow rotates in the same direction as the gas disk surrounding the star. This strongly supports the idea that the outflow plays an important role in dissipating the rotational energy.

Furthermore, ALMA clearly shows that the outflow is launched not from the vicinity of the itself, but rather from the outer edge of the disk. This morphology agrees well with the "magnetocentrifugal disk wind model." In this model, gas in the rotating disk moves outward due to the centrifugal force and then moves upward along the magnetic field lines to form outflows. Although previous observations with ALMA have found supporting evidence around a low-mass protostar, there was little compelling evidence around massive protostars because most of the massive-star forming regions are rather distant and difficult to investigate in detail.

"In addition to high sensitivity and fidelity, high resolution submillimeter-wave observation is essential to our study, which ALMA made possible for the first time. Submillimeter waves are a unique diagnostic tool for the dense innermost region of the outflow, and at that exact place we detected the rotation," explained Hirota. "ALMA's resolution will become even higher in the future. We would like to observe other objects to improve our understanding of the launching mechanism of outflows and the formation scenario of with the assistance of theoretical research."

ALMA also imaged rotation of a gas jet from a low-mass protostar. Please read the press release "Baby Star Spits a "Spinning Jet" As It Munches -Down on a "Space Hamburger"" from the Academia Sinica Institute of Astronomy and Astrophysics, Taiwan.

The color shows the motion of the gas; red shows gas moving away from us, whereas blue shows gas moving toward us. The disk is shown in white. Credit: ALMA (ESO/NAOJ/NRAO), Hirota et al.

Explore further: ALMA returns to boomerang nebula: Companion star provides chilling power of 'coldest object in the universe'

More information: Tomoya Hirota et al, Disk-driven rotating bipolar outflow in Orion Source I, Nature Astronomy (2017). DOI: 10.1038/s41550-017-0146

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Tuxford
1.7 / 5 (9) Jun 12, 2017
Stars formed in such a process should have very rapid rotation, but this is not the case. The stars observed in the Universe rotate more slowly.

Because most stars grow naturally from new matter created there-within. But this obvious answer is not enough for the common merger maniac.

The outflow rotates in the same direction as the gas disk surrounding the star.

Since the ejected gas originates from within the star itself, rather than from without from any random direction.
jonesdave
4.9 / 5 (9) Jun 12, 2017
Stars formed in such a process should have very rapid rotation, but this is not the case. The stars observed in the Universe rotate more slowly.

Because most stars grow naturally from new matter created there-within. But this obvious answer is not enough for the common merger maniac.

The outflow rotates in the same direction as the gas disk surrounding the star.

Since the ejected gas originates from within the star itself, rather than from without from any random direction.


Wrong. Lol.
antialias_physorg
3.7 / 5 (11) Jun 12, 2017
from new matter created there-within

Bold statement. Totally at odds with all known conservation laws. What's the mechanism?
Since the ejected gas originates from within the star itself, rather than from without from any random direction.

Stars created 'from within' should not show rotation at all (why should this magic creation of mass carry angular momentum? And why only in one direction? For that matter: Where does this miraculous star formation 'from within' start? Does it just start popping out of nowhere and decide "here be a star"?)

I know, you've been asked these questions a million times and never answered - but it still pays to point out the supreme idiocy of your statements. You're on a science site - and you expect to make anything but a fool of yourself with these claims? Really? I mean...really? Get help, man.
GuruShabu
1.4 / 5 (7) Jun 12, 2017
Any contraction mass cannot shrink without losing angular momentum.
Present physics based only on gravitation fails to do that.
The only explanation is transferring angular momentum through the magnetic field surrounding the contracting mass.
In fact, it is the electrical field - which is 10 powered to 39 times bigger than the gravitational field - not the gravitational field that attracts the plasma to begin the process of star formation.
GuruShabu
1.3 / 5 (7) Jun 12, 2017
Also, the trend of humanizing natural phenomena giving names such as, "birth cry, the eye of god (Hélix nebula or NGC 7293) " are misleading nomenclature. The only purpose of this such a name is attracting lay people to the subject.
This is the present trend to do science by press release and consensus.
Hat1208
3.4 / 5 (5) Jun 12, 2017
@GuruShabu

You are not a guru. Guru's are teachers not liars.
antialias_physorg
5 / 5 (6) Jun 12, 2017
Any contraction mass cannot shrink without losing angular momentum.

Whut? Dude. Look up what angular momentum is.
https://en.wikipe...momentum
(Hint: look for the words 'conserved quantity' and try to understand what that means)
Tuxford
1.4 / 5 (7) Jun 12, 2017
from new matter created there-within

Bold statement. Totally at odds with all known conservation laws. What's the mechanism?

Once again, the common merger maniac is not really listening. Or maybe, he can't, since limited intellectual bandwidth limits his conceptual capability.

As I've previously stated many times to no avail, conservation is not violated in LaViolette's SQK, since matter simply enters our observable realm from the ever present surrounding whole in which all observable matter is simply a subset. We exist within the whole. The underlying unobservables under the proper relative diffusive concentration, suddenly begin to combine in a propagating transformation reaction that we can then observe as matter.

What if such a scenario is true? Would that not inspire physics to evolve? But too many grey-bearded vested merger maniacs must die off first, before such a revolution in thinking can emerge. Deny, deny, deny, just like the White House.
Whydening Gyre
5 / 5 (2) Jun 12, 2017
Tux,
By the time we actually SEE a star "birth", the fusion process within (starting at it's densest point - usually the center) has been percolating for 10s, maybe even hundreds of years.
This can only be physically initiated by additive density process (thereby increasing pressure and, subsequently, heat).
There is no magic "new matter" created in the center whose resource supply is NOT the physically closest in-falling matter.
Tuxford
1 / 5 (5) Jun 12, 2017
Tux,
There is no magic "new matter"...

The point bypasses you as well. I will try to simplify for inquiring minds.

Imagine a toy box filled with various colored balls. All balls are small, except for blue ones, which are all bigger. Only the bigger blue balls are visible, by other blue balls. All other smaller colored balls are invisible to the blue balls.

Then imagine that the big blue balls contain invisible smaller balls of other colors as well. In fact, the reaction of various small balls inside the space occupied by a blue ball is itself what is visible as a blue ball. The reaction produces other small balls of different colors. And feeding the reaction is other small balls diffusing therein.

There exists a standard proportion of various small balls of various colors everywhere. However, the ongoing reaction distorts the ratio of colors of small balls nearby, creating the effects of force and field.

So, matter is blue. The small balls still exist, however.
antialias_physorg
5 / 5 (6) Jun 13, 2017
The underlying unobservables under the proper relative diffusive concentration, suddenly begin to combine in a propagating transformation reaction that we can then observe as matter.

Are you claiming undetectable matter suddenly becomes detectable? And why at that particular point (and not, say, everywhere)?

Man, this is so crazy we need a new category for this. Maybe 'willfully constructed insanity' or something.
Tuxford
1 / 5 (3) Jun 13, 2017
Are you claiming undetectable matter suddenly becomes detectable? And why at that particular point (and not, say, everywhere)?

Catching on, a bit, maybe? Remember, the small 'marbles' are not physical, yet they exist. There is lot's of space for them inside any atom.

The local relative concentration of various colored small 'marbles' determines the local fertility of that region for igniting a new big blue reaction of matter. Inside the cores of larger stars then, the local concentration is altered dramatically as the ongoing blue reactions are sinking and sourcing various colored marbles at accelerated rates, with the distorted concentrations therein producing extreme forces as well. The reaction then propagates like wildfire.

In deep space, the conditions are not at all fertile. It takes a very long time for statistics to produce the fertile conditions leading to a new ignition. Still it occurs, yielding inter-galactic gas clouds.
Whydening Gyre
5 / 5 (2) Jun 13, 2017
Tux,
There is no magic "new matter"...

The point bypasses you as well. I will try to simplify for inquiring minds.

Imagine a toy box filled with various colored balls. ...

you context-edited my comment.
What YOU are bypassing is the fact that gravitationally driven pressure (and it's subsequent heat) forming new elements of varying degrees of density is happening all the time. Generally speaking, a convective force is constantly in play, in AND out from the center (generally accepted as the densest location).
As to your blue balls?
Sorry I enquired...
antialias_physorg
5 / 5 (5) Jun 13, 2017
Remember, the small 'marbles' are not physical, yet they exist.

Erm..what 'small marbles'? What are you smoking?

There is lot's of space for them inside any atom.

That's not how atoms work - and every experiment (particularly any that shows interference) demonstrates this.


The local relative concentration of various colored small 'marbles' determines the local fertility of that region for igniting a new big blue reaction of matter. Inside the cores of larger stars then

And yet in all the time we have been able to measure (and observe) mass at the atomic level that has never been recorded. Why do you think that is?

Weird, ain't it: Theory should match observation - and yours doesn't on sooo many levels it isn't even funny.
Tuxford
1 / 5 (3) Jun 13, 2017
You guys must be members of the grey-beard society, unable to really think abstractly anymore. This should be obvious, but you still can't see it. You are too vested in the established paradigm.

As I have said before, only those firmly grasping systems theory have a chance. And I know from experience, most simply have no chance.

You have to get over the common assumption that only that which is observable exists. That space is simply empty, when in fact it is full to the brim with that which never be observed: the tiny balls, or marbles that under the right conditions begin to react in transformation, as if lit up like a fire. What are the marbles? We can never actually know.
Whydening Gyre
5 / 5 (2) Jun 13, 2017
You guys must be members of the grey-beard society, unable to really think abstractly anymore. This should be obvious, but you still can't see it. ...

Mine's red n blonde. And Abstract is my middle name...
... the tiny balls, or marbles that under the right conditions begin to react in transformation, as if lit up like a fire. What are the marbles? ...

Guess you could find out - if they weren't lost, already...
antialias_physorg
4.2 / 5 (5) Jun 14, 2017
As I have said before, only those firmly grasping systems theory have a chance.

Yep. You should give it a try some time.

You have to get over the common assumption that only that which is observable exists

But we should totally accept that unobservables exist because...you say so? Know who operates like this? Priests.

You're just making stuff up and then expect everyone to believe it? Really? If we were on some fundamentalist christian site I'd say you'd stand about a 1 in a million chance. But here? Really? You expect anyone to buy this? I mean...really?

What are the marbles? We can never actually know.

Well I know what some of them are...the ones you lost.

bschott
3 / 5 (2) Jun 14, 2017
But we should totally accept that unobservables exist because...you say so? Know who operates like this? Priests.

You believe in cosmology based on "dark matter" and defend the existence of that unobservable every chance you get....Padre.

You're just making stuff up and then expect everyone to believe it?

Sounds like Tux has sold out to mainstream ideals....what a shame.
If we were on some fundamentalist christian site...

You would be around about 20 vocal devout ready to crucify anyone with different ideas, 20 who vocally question the beliefs of the devout because they understand there is no place for that kind of rigidity when it comes down to matters of faith, and a bunch of people entertained/offended/disgusted by the interactions of these people....

Hmmmmm.......

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