Formation of Brown Dwarfs in filaments?

In summary, the formation of brown dwarfs in filaments is a result of the collapse of irregular molecular clouds. This process can also be seen on cosmological scales, where filaments form from collapsing gas and eventually nucleate stars, including hypothetical brown dwarfs.
  • #1
Florens
7
1
Hello, I'm in grade 12, writing a term paper on brown dwarfs and am currently looking at their formation. I have now come across the formation of brown dwarfs in so-called "filaments" (link to the page below), but can't find out anything about them, except for the fact that they are filamentary connections of visible and dark matter between larger galaxy clusters and superclusters with an even higher local galaxy density. These filaments, however, I think are not meant.

https://academic.oup.com/mnras/article/332/3/L65/1052962
(Filaments were mentioned in the Abstract)

Thanks
 
  • Like
Likes berkeman
Astronomy news on Phys.org
  • #3
Yes, but it's a more general statement about how molecular clouds collapse.
In an idealised scenario, where a cloud is spherically symmetric, you could expect it all to collapse into nice and clean protostellar accretion disc.
But clouds are typically rather irregular, so the collapse involves a number of discs and more elongated overdense regions in-between. Those elongated regions are the filaments in question.
The collapse mechanism on cosmological scales that you had found earlier is similar, since it also involves collapsing gas - there, too, you can see local overdensities and elongated filaments (if you'd like to see how, look up the Illustris simulation).

If you go here:
https://www.astro.ex.ac.uk/people/mbate/Cluster/pr.html
you'll find a number of images and animations showing a simulated collapse. It's by the principal author of the paper you cite in the OP. You can see those filaments evolve from a cloud of gas and then nucleate stars.
Here's the same thing on youtube:

It's essentially what's shown in the fig.2 of the paper.
 
  • Like
Likes Ken G, Florens, berkeman and 1 other person
  • #4
Bandersnatch said:
Ja, aber es ist eine allgemeinere Aussage darüber, wie Molekülwolken kollabieren.
In einem idealisierten Szenario, in dem eine Wolke kugelsymmetrisch ist, könnte man erwarten, dass alles in eine schöne und saubere protostellare Akkretionsscheibe kollabiert.
Aber Wolken sind typischerweise eher unregelmäßig, sodass der Kollaps eine Reihe von Scheiben und dazwischen liegende, langgestrecktere, überdichte Regionen umfasst. Diese länglichen Bereiche sind die fraglichen Filamente.
Der Kollapsmechanismus auf kosmologischen Skalen, den Sie zuvor gefunden haben, ist ähnlich, da es auch um kollabierendes Gas geht - auch dort können Sie lokale Überdichten und verlängerte Filamente sehen (wenn Sie sehen möchten, wie, sehen Sie sich die Illustris-Simulation an).

Wenn du hier hin gehst:
https://www.astro.ex.ac.uk/people/mbate/Cluster/pr.html
Sie finden eine Reihe von Bildern und Animationen, die einen simulierten Einsturz zeigen. Es ist vom Hauptautor des Artikels, den Sie im OP zitieren. Sie können sehen, wie sich diese Filamente aus einer Gaswolke entwickeln und dann Sterne bilden.
Hier ist das gleiche auf youtube:

Es ist im Wesentlichen das, was in Abb. 2 des Papiers gezeigt wird.

Ok thanks, that was very helpful. One quick question about the video. The white dots ( stars) that are ejected from the star cluster. Are these hypothetical brown dwarfs?
 
  • #5
Florens said:
The white dots ( stars) that are ejected from the star cluster. Are these hypothetical brown dwarfs?
Yes.
 

FAQ: Formation of Brown Dwarfs in filaments?

What are Brown Dwarfs?

Brown dwarfs are substellar objects that are too massive to be considered planets but not massive enough to sustain hydrogen fusion reactions in their cores, which is the defining characteristic of stars. They typically have masses between approximately 13 and 80 times that of Jupiter.

How do Brown Dwarfs form in filaments?

Brown dwarfs form in dense, elongated structures known as filaments within molecular clouds. These filaments are regions where the gas density is higher, leading to gravitational instability. As the gas within these filaments collapses, it can fragment into smaller clumps, some of which are not massive enough to form stars and instead form brown dwarfs.

What role do filaments play in the formation of Brown Dwarfs?

Filaments serve as the birthplaces for brown dwarfs by providing a dense and elongated environment where gravitational collapse can occur. The high-density regions within filaments are crucial for the fragmentation process that leads to the formation of brown dwarfs and other substellar objects.

Are Brown Dwarfs more likely to form in filaments compared to other regions of molecular clouds?

Yes, brown dwarfs are more likely to form in filaments compared to other regions of molecular clouds. Filaments have higher densities and are more prone to gravitational instability, making them ideal sites for the formation of brown dwarfs and other low-mass objects.

What observational evidence supports the formation of Brown Dwarfs in filaments?

Observational evidence supporting the formation of brown dwarfs in filaments includes high-resolution images from telescopes like the Atacama Large Millimeter/submillimeter Array (ALMA) and the Herschel Space Observatory. These images reveal the presence of dense filaments within molecular clouds and show young brown dwarfs and protostellar objects within these structures, indicating that filaments are active sites of substellar formation.

Similar threads

Replies
21
Views
3K
Replies
1
Views
1K
Replies
2
Views
2K
Replies
1
Views
2K
Replies
2
Views
2K
Replies
6
Views
5K
Replies
6
Views
3K
Back
Top