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
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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
 
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  • #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.
 
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  • #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.
 

1. What is a brown dwarf?

A brown dwarf is a type of celestial object that falls in between a star and a planet in terms of mass. It is too massive to be considered a planet, but not massive enough to sustain nuclear fusion in its core like a star does.

2. How are brown dwarfs formed in filaments?

Brown dwarfs are formed in filaments, or elongated structures of gas and dust, through the process of gravitational collapse. As the filament collapses, it fragments into smaller clumps, some of which may have enough mass to become brown dwarfs.

3. What role do filaments play in the formation of brown dwarfs?

Filaments play a crucial role in the formation of brown dwarfs as they provide the initial structure for gravitational collapse to occur. Without filaments, it is unlikely that brown dwarfs would form.

4. Can brown dwarfs form in isolation, or do they always need filaments?

Brown dwarfs can form in isolation, but the likelihood of this happening is much lower compared to their formation in filaments. Filaments provide the necessary conditions for gravitational collapse to occur, increasing the chances of brown dwarf formation.

5. How do scientists study the formation of brown dwarfs in filaments?

Scientists use a combination of observations and simulations to study the formation of brown dwarfs in filaments. They observe young star-forming regions where filaments and brown dwarfs are known to exist, and also use computer simulations to model the process of gravitational collapse and brown dwarf formation.

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