Formation of Brown Dwarfs in filaments?

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Discussion Overview

The discussion centers on the formation of brown dwarfs, particularly in relation to filamentary structures within molecular clouds. Participants explore the role of these filaments in the star formation process, referencing both theoretical models and simulations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant seeks information on the formation of brown dwarfs in filaments, noting a lack of clarity on the term "filaments" as used in the context of galaxy structures.
  • Another participant suggests that filamentary structures in molecular clouds are significant for star formation, referencing a paper that discusses this morphology.
  • A participant elaborates on the collapse of molecular clouds, explaining that irregularities lead to elongated overdense regions, which are the filaments being discussed.
  • There is mention of the Illustris simulation as a visual representation of how filaments evolve from gas clouds and lead to star formation.
  • A question arises regarding the nature of white dots (stars) ejected from star clusters in a simulation, with a participant confirming they could represent hypothetical brown dwarfs.

Areas of Agreement / Disagreement

Participants generally agree on the significance of filamentary structures in the context of star formation, but the specific implications for brown dwarf formation remain less clear. There is no consensus on the exact nature of the filaments or the relationship to brown dwarfs.

Contextual Notes

The discussion includes references to specific simulations and papers, but lacks detailed exploration of the underlying assumptions or definitions of "filaments" in different contexts.

Who May Find This Useful

Readers interested in astrophysics, particularly in the formation of stars and brown dwarfs, as well as those studying molecular clouds and cosmic structures.

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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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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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?
 
Florens said:
The white dots ( stars) that are ejected from the star cluster. Are these hypothetical brown dwarfs?
Yes.
 

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