First clear image made of accretion disk surrounding young star

April 20, 2017 by Bob Yirka report
An illustration of an accretion disk feeding a central young star, or protostar, and the gaseous jet ejected from the protostar. Credit: Yin-Chih Tsai/ASIAA

(Phys.org)—A team of researchers from the U.S. and Taiwan has captured the first clear image of a young star surrounded by an accretion disk. In their paper published in the journal Science Advances, the team describes how the image was captured and details of their find.

Astrophysics have theorized that accretion disks form around young stars acting as food, helping the young star to grow bigger. Such an accretion disk would also make up the material that would over time accrete into planets. But until now, no clear image of an accretion disk had been made because the technology to do so did not exist. Now, thanks to by the team and the ALMA radio telescope in Chile, that has changed.

ALMA came online just four years ago—at a cost of $1.4 billion, it holds the record for the most expensive radio telescope ever built. But it also offers unprecedented resolution, capturing images in sharp detail that have appeared as fuzzy blobs in prior images. That resolution allowed the researchers to zoom in on a young star named IRAS 05413-0104 (part of the HH212 system and believed to be just 40,000 years old) that had around it a rotating accretion disk. Such disks are believed to be made of matter such as silicate, iron and other interstellar matter, and provide a steady source of food for the star. And because the disks are triple layered with brighter outer layers, the researchers describe it as looking like a hamburger.

The video will load shortly
Video explaining how a “dusty hamburger” (an accretion disk) feeds a central young star, or protostar, during the onset of an extra-solar system. Credit: Chin-Fei Lee/Lauren/ASIAA

The captured image lays to rest one critique of the prediction of around , which was that the magnetic field from the core of the star would be so strong that it would prevent the accretion disk from spinning, thus preventing its ability to gather matter. That is clearly not the case, as the new image shows. Also seen in the image were gaseous jets ejected from the star, which appear to pierce the hamburger at its center.

It is believed that more information about the formation of will contribute to understanding both the history of our sun and how planets form, perhaps offering a better way of filtering star systems while searching for signs of life beyond our own planet.

Jet and disk in the HH 212 protostellar system: (a) A composite image of the jet, produced by combining images from different telescopes. The orange image around the center shows the accretion disk at 200 AU resolution. (b) Close-up of the center of the dusty disk at 8 AU resolution. Asterisks mark the possible position of the central protostar. A dark lane is seen in the equator. Our solar system is shown in the lower right corner for size comparison. (c) An accretion disk model that can reproduce the observed dust emission in the disk. Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al.

(a) The accretion disk model with the disk surface temperature. (b) The model dust emission map derived from the disk model. This model map is roughly the same as the observed map of the disk. Credit: Lee et al.

Explore further: Collisions generate gas in debris disks

More information: Chin-Fei Lee et al. First detection of equatorial dark dust lane in a protostellar disk at submillimeter wavelength, Science Advances (2017). DOI: 10.1126/sciadv.1602935

Abstract
In the earliest (so-called "Class 0") phase of Sun-like (low-mass) star formation, circumstellar disks are expected to form, feeding the protostars. However, these disks are difficult to resolve spatially because of their small sizes. Moreover, there are theoretical difficulties in producing these disks in the earliest phase because of the retarding effects of magnetic fields on the rotating, collapsing material (so-called "magnetic braking"). With the Atacama Large Millimeter/submillimeter Array (ALMA), it becomes possible to uncover these disks and study them in detail. HH 212 is a very young protostellar system. With ALMA, we not only detect but also spatially resolve its disk in dust emission at submillimeter wavelength. The disk is nearly edge-on and has a radius of ~60 astronomical unit. It shows a prominent equatorial dark lane sandwiched between two brighter features due to relatively low temperature and high optical depth near the disk midplane. For the first time, this dark lane is seen at submillimeter wavelength, producing a "hamburger"-shaped appearance that is reminiscent of the scattered-light image of an edge-on disk in optical and near infrared light. Our observations open up an exciting possibility of directly detecting and characterizing small disks around the youngest protostars through high-resolution imaging with ALMA, which provides strong constraints on theories of disk formation.

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HannesAlfven
1 / 5 (11) Apr 20, 2017
The tireless campaign to minimize the importance of electromagnetism in space rolls on, and let's be clear that those who seek to lend gravity all of this power have not taken the time to fully understand the many nuances of the debate. Those who cheer them on like a team sport seem unaware of the inherent gamble: If this approach proves wrong, then all we will have to show for this current era is the observations and lessons about the sociology of science. Many millions of hours of human activity and billions of dollars in public money rest upon the wisdom of these inferences; the idea that such inferences would be made without a very detailed analysis of the arguments on both sides displays an eagerness to spend vast human resources without concern for where the history will end up on these questions.
someone11235813
3 / 5 (2) Apr 20, 2017
Maybe by the time our Sun has destroyed all life in the inner solar system, intelligent life will just be coming into existence in that distant proto solar system. Kant would have enjoyed this video.
Tuxford
1 / 5 (7) Apr 21, 2017
The gas jets are the source of the material falling into the disk, having been ejected from the star after forming new matter therein. But a merger maniac would never think such a thing. So the jets are not even given due consideration, but only mentioned as curiosity.
FredJose
1 / 5 (12) Apr 21, 2017
Star formation -> what is it? How does it happen? What triggers the ignition?

The unsolved mystery remains. The observations pile up, the theories become wilder and wilder but the enigma of stars forming all by themselves from clouds of gas without any external intelligent help and self-igniting remains as obscure and obdurate a problem as ever.

If you do not know how stars came into existence then you just about know nothing else about the origin of the whole universe - no matter how you throw wild, speculative theories around.
FineStructureConstant
4.7 / 5 (13) Apr 21, 2017
The gas jets are the source of the material falling into the disk
And just when we think we've heard the last word in foolishness from Tux, he utters something so gob-smackingly asinine, and of such mind-crushing vapidity, that we are almost lost for words ourselves. Almost, but not quite.

Tux, you're obviously unaware that the Herbig-Haro objects which form the "knots" in these jets, and indeed in all similar jets with HH objects, are invariably seen to move *outwards* from the protostellar object in the center of systems like this one.
the jets are not even given due consideration, but only mentioned as curiosity.
Wrong again - such jets are the subject of countless detailed studies and analyses.

It's a shame really that you're not even prepared to learn about such things, preferring instead the comfy warm glow of ignorance, and reliance on the mindless repetition of some other idiot's half-baked and fanciful notions in a vain attempt to impress people.
krzychu01230
1 / 5 (9) Apr 21, 2017
Geometry of this object resembles Peratt plasma instability
FineStructureConstant
4.5 / 5 (16) Apr 21, 2017
Geometry of this object resembles Peratt plasma instability
...in much the same way that a heap of horseshit resembles Mount Everest.
Hat1208
4.6 / 5 (9) Apr 21, 2017
@FineStructureConstant

Good on ya!
bschott
1.9 / 5 (9) Apr 21, 2017
The gas jets are the source of the material falling into the disk
And just when we think we've heard the last word in foolishness from Tux, he utters something so gob-smackingly asinine, and of such mind-crushing vapidity, that we are almost lost for words ourselves. Almost, but not quite.

LMAO...maybe before you insult somebody, you should make sure they are not correct. Check the composition of masers against the theorized composition of the Kuiper belt and oort cloud bodies. They correlate...he's right.
@FineStructureConstant
Good on ya!

Now I see why you only lick ass here and never post anything scientific in nature. Way to cheerlead an abusive moron who is completely incorrect in his "knowledge."
FineStructureConstant
4.6 / 5 (10) Apr 21, 2017
blahschott.
maybe before you insult somebody, you should make sure they are not correct.
TuxWindBag subscribes to the debunked notions of LaViolette, and believes against all evidence to the contrary that matter is created in vast amounts from nothing and can provide no theoretical basis for such a belief. His "science" cannot therefore be checked for correctness, and carries no more weight than any other set of religious beliefs.
Way to cheerlead an abusive moron who is completely incorrect in his "knowledge."
I wrote a thesis at Uni 30 years ago on HH objects - I knew then what I was talking about, and I still do.

As for yourself, when measured up against your own clueless peers, you may appear to know a great deal about physics but - as has been pointed out here numerous times by those who really do know what they're talking about - your "knowledge" is more full of holes than a sieve, and about as substantial as a Belgian waffle.
FineStructureConstant
4.6 / 5 (9) Apr 22, 2017
@bullschott: OK, I'll bite
Check the composition of masers
Astrophysical masers occur in various types of places, where the conditions and composition of surrounding material vary widely. However, various species of molecule in such places can exhibit masing activity, among them being OH, H2O, NH3, SiO, HCN and others. So, are you talking about the masing molecules, or the composition of the matrix of material in which they find themselves?

And in any case WTF has any of that got to do with HH objects? HH objects form at places where jets collide with the ISM, are composed almost entirely of H and He, emit in IR and optical wavelengths over a range of frequencies, and do not exhibit masing.
theorized composition of the Kuiper belt and oort cloud bodies
Theorized? whose theories? Why not just stick to what is mentioned in the article, and talk about accretion disks, which change in composition over the lifetime of the disk?
FineStructureConstant
4.6 / 5 (9) Apr 22, 2017
They correlate...he's right.
Fatuous comment! The number of houses built in NY State in the last 30 years correlate rather well with the number of spacecraft launched in the same period, but the one set of data has nothing to do with the other. Correlation does not imply causal link, dum-dum.

And if Tux were right about jets feeding accretion disks, we'd be able to see the vast amounts of material falling back down in curtains or clumps of material which would be highly visible. We don't see 'em.

Neither does Tuxiot posit any mechanism by which a highly collimated jet of material moving away from the protostar at high velocities can alter its' momentum so drastically that it can flow outwards and downwards to the disk in order to "feed" it.

These are the kinds of things one needs to consider - consistency, observing conserved quantities, adding up the numbers. Neither you nor Tux bother with any of this: for you guys, making things sound "science-y" is all that's needed.
FineStructureConstant
4.4 / 5 (7) 23 hours ago
Another observation: even if there were molecules capable of masing present in the jets or HHO's, no masing would be possible: and that's down to one salient fact.

Notwithstanding the fact that the material in the jets and HHO's is moving outward at high speed, it's a hot gas (actually a partially-ionized plasma) which means that the particles in the gas are moving randomly around at high speeds within the body of the gas/plasma. This means that no portion of the object is able to achieve the velocity coherence necessary for any significant degree of masing.

And even if a portion of the jet or HHO were to momentarily achieve a condition of masing, the spectral absorption from the surrounding gas/plasma would most effectively attenuate any such masing signal to nothing.
RealityCheck
1 / 5 (2) 12 hours ago
@FineStructureConstant.

FSC, while I do NOT agree with every assertion, claim etc made by Tuxford, I note that your responses are of 'double standard' type. Case in point:
blahschott.
maybe before you insult somebody, you should make sure they are not correct.
TuxWindBag subscribes to the debunked notions of LaViolette, and believes against all evidence to the contrary that matter is created in vast amounts from nothing and can provide no theoretical basis for such a belief. His "science" cannot therefore be checked for correctness, and carries no more weight than any other set of religious beliefs.
Your above observation/criticism is exactly applicable, word for word, to Big Bang, Inflation etc etc. So using that 'argument' to 'debunk' Tuxford is, as it were, a 'double-edged sword'. Take extra care when 'wielding' same, hey?
...about as substantial as a Belgian waffle.
Speaking of "Belgian", BB 'creationism' was a Belgian Priest's religious fantasy.
FineStructureConstant
5 / 5 (4) 6 hours ago
Your above observation/criticism is exactly applicable, word for word, to Big Bang, Inflation etc
Only if one has failed completely to understand the fundamental difference between

(a) Tux/La Violette's baseless conjectures plucked out of thin air, with no evidence or carefully-constructed theories to back them up - in fact they ignore the evidence which very clearly disproves their ideas - no quantitative predictions and hence no means of proving or falsifying said conjectures.

(b) The vast amount of evidence collected over decades which has led many to construct theories, like BB and inflation, in an attempt not only to explain the observations, but also to provide quantitative predictions which can be tested, in other words, these theories are falsifiable.

Theories which can be lumped under category (a) are unfalsifiable, and hence ain't science. Those under (b) ARE falsifiable, no matter how kookie they may sound, and hence ARE science.
RealityCheck
1 / 5 (1) 5 hours ago
@FineStructureConstant.
(a) Tux/La Violette's baseless conjectures plucked out of thin air, with no evidence or carefully-constructed theories to back them up...
Ok. HOWEVER, it's the SAME for BB/INFLATION; now being 'disowned' by Penrose/Steinhardt, saying they were NOTIONS that NEVER had any tenable scientific basis for them. See the similarities in critique?
(b) The vast amount of evidence collected over decades which has led many to construct theories, like BB and inflation, in an attempt not only to explain the observations, but also to provide quantitative predictions which can be tested, in other words, these theories are falsifiable.
First please see response to ( a). Then catch up with mainstream discoveries/reviews of late increasingly showing old BB etc myths NEVER 'scientific'.
Those under (b) ARE falsifiable,
But BB/Inflation etc ALSO 'unfalsifiable'! The only 'support' WAS notional/unsupportable assumption/interpretations etc. Circuitous.

See?
FineStructureConstant
5 / 5 (3) 3 hours ago
@RC: Theory with quantitative predictions => experimentation / observation => falsifiability. Science.

Of course many scientists are not totally happy with BB/Inflation, and some of those come up with alternatives - that's all been true for years, decades! Everybody knows this, so what's new? What exactly are you adding to this long-running debate which hasn't been said a thousand times?

But as working hypotheses, BB/Inflation/etc., at least permit work to be done by the few who dedicate themselves to such investigations. The vast majority, like the people in the article, get on with other stuff. Situation normal, nothing new to see here, folks, move on.

Meanwhile, the nutcases who believe in the barren "theories" propounded by the likes of EU, LaViolette, Velikovsky - yes, and your own rambling, flatulent cosmology-without-numbers-or-predictions - are floundering in the muddy waters of ignorance, without a snowball's chance in hell of ever being recognized as scientists.

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