Dust Traps and Planet Factories

From ESO. Astronomers now know that planets around other stars are plentiful. But they do not fully understand how they form and there are many aspects of the formation of comets, planets and other rocky bodies that remain a mystery. However, new observations exploiting the power of the ALMA telescope array are now answering one of the biggest questions: how do tiny grains of dust in the disc around a young star grow bigger and bigger — to eventually become rubble, and even boulders well beyond a metre in size?

Computer models suggest that dust grains grow when they collide and stick together. However, when these bigger grains collide again at high speed they are often smashed to pieces and sent back to square one. Even when this does not happen, the models show that the larger grains would quickly move inwards because of friction between the dust and gas and fall onto their parent star, leaving no chance that they could grow even further.

Somehow the dust needs a safe haven where the particles can continue growing until they are big enough to survive on their own [1]. Such "dust traps" have been proposed, but there was no observational proof of their existence up to now.

Nienke van der Marel, a PhD student at Leiden Observatory in the Netherlands, and lead author of the article, was using ALMA along with her co-workers, to study the disc in a system called Oph-IRS 48 [2]. They found that the star was circled by a ring of gas with a central hole that was probably created by an unseen planet or companion star. Earlier observations using ESO's Very Large Telescope had already shown that the small dust particles also formed a similar ring structure. But the new ALMA view of where the larger millimetre-sized dust particles were found was very different!

[ErgoCogita]

I could be wrong but I think specific gas laws work against clouds of gas being "the" seed for planetary formation due to their affinity for even distribution. Particles don't normally behave like gasses and therefore can clump just fine and on their own. It is far more likely, I think, that particles formed first and gas could then clump due to gravity being strong enough to overcome that "affinity".

[CaptainNero]

Im very impressed at the size of the site, , , this observatory is on a massive scale and on top off a mountain, , ,

[PMW]

that's the way I understand it, although they aren't technicality considered planets until they finished clearing out their perspective orbits.

[oscariwu]

Always looking forward to the groundbreaking work ALMA is already undertaking. Great video, SpaceRip, thanks for posting it.

[Uriel]

Actually, astronomers are often admittedly daft as new data (which we're getting all the time) conflicts with previous cosmological models.

We used to think (for instance) that gas giants couldn't form within the hot-zone of a star, and yet we're encountering many astounding examples that prove that this just isn't so.

We work with the knowledge we got, and the more we learn, more clear it is how little we actually understand.

[pickymoon]

Thank you for the honor of your utterly tactful comment on Chile, dear first world citizen.

[Journeyman]

I don't get the whole dust to planets scenario. It is most likely that gas planets formed first then their gravitational pull, pulled in the dust particles and under immense pressure of the gas giant were pressed tighter and tighter till a rocky planet was formed and displace the gaseous part of the now rocky planet.

[masudhasan]

Planet Factory? Almost felt like the Rainbow Factory when it came to my head.

[TubbyTronPwnzU]

3:01 how does one see the sky like that? and at 0:06 is that the sun? what sorcery is this?

[HelpmelamEnglish]

Yes you are correct but you are also forgetting that our time on this planet is limited. The more we look into space the more we notice how many objects there are out there that could destroy most or even all the the life here! Learning about what the cosmos is comprised of is a worthwhile adventure. Also our planet is running out of resources, the human population continues to rapidly expand and it will only get harder for US ALL to live here, don't forget our changing climate too ;)

[tiagotiagot]

So planets clear out their orbits before they become planets?

[Jex]

In theory, if you had enough robots (billions), it wouldn't be too difficult; you would just have to gather loose matter into clumps, which gives them enough gravity to gather more loose matter, eventually making a nebula, which will eventually make stars, which will eventually make planets.
.
There would be no fast way to do it but in theory it wouldn't be hard; it would just require a massive migration / collection of mass.

[CaptainOfGames]

1 : That's the milky way. If you drive very far away from any city lights, you just might see it. But it's very dim.

2 : That's the moon.

[SodapopSays]

0:33
another video behind the video???

[malecat]

Oh they're in good condition for sure, top drawer.

[CaptainOfGames]

#1: That's the milky way. If you drive very far away from any city lights, you just might see it. But it's very dim.

#2: That's the moon.

[mskiUSMC]

This looks like a clue as to how many solar systems form...

[downfall]

To see the sky like that you have to climb high above where most clouds form and get away from all sources of light pollution.

[Niosus]

exactly. A blob in that shape. It's clearly not a ring! That's the important part. They have never discovered a not-ring and to make the theory work the need a not-ring. So this blurry blob shows them that the theory is on the right track.

[esdev]

"Planet factory" is such a cool name. :D