<p>The crucial point here is that the initial large cloud does not have a constant density throughout but contains many random smaller blobs with a higher density. Because of the higher density, these will collapse faster than the whole cloud would. So you end up with a star cluster rather than one supermassive star.</p>

CC BY-SA 4.0
2022-01-19T23:56:45.947Z
This isn't the main reason that fragmentation occurs.
ProfRob
CC BY-SA 4.0
2022-01-20T20:45:18.417Z
@ProfRob One needs density irregularities in the first place for fragmentation to occur
Thomas
CC BY-SA 4.0
2022-01-21T00:00:35.047Z
The correct explanation is here https://en.m.wikipedia.org/wiki/Jeans_instability The presence of density perturbations is not sufficient to cause fragmentation. There are other conditions that are met in collapsing protostellar clouds.
ProfRob
CC BY-SA 4.0
2022-01-21T08:28:19.570Z
@ProfRob Density irregularities as such may not be sufficient for fragmentation but they are necessary. Without them the giant cloud would just collapse as a whole towards its center.
Thomas
CC BY-SA 4.0
2022-01-19T22:18:19.937Z
2022-01-19T22:18:19.937Z
Thomas
<p>Imagine we have a stellar cloud sufficiently massive to generate N high mass stars, what is the reason for this scenario not to happen? Because I know that when the jeans instability happens a star is born. So the critical mass (Jean's) associated with this instability as a lower limit is the one which makes it more probable to form low mass stars or that is what I interpret from what I studied. If it not the case, please let me know.</p>
<p>Another thing I have read is that the critical mass is proportional to  <span class="math-container">$1/\sqrt{\rho}$</span>  so when the cloud is collapsing it can fragment in more stars because the density <span class="math-container">$\rho$</span> increases during this scenario, I think this is another reason why low mass stars are more common.
So my question is, are these things I mentioned the fundamental reasons why more low mass stars are generated? or there is another reason? or is what I said wrong?</p>

<star-formation>
Massive star formation
martín canullán
# Massive star formation

(Asked by: username_0 on 2022-01-18)

Imagine we have a stellar cloud sufficiently massive to generate N high mass stars, what is the reason for this scenario not to happen? Because I know that when the jeans instability happens a star is born. So the critical mass (Jean's) associated with this instability as a lower limit is the one which makes it more probable to form low mass stars or that is what I interpret from what I studied. If it not the case, please let me know.

Another thing I have read is that the critical mass is proportional to $1/\sqrt{\rho}$ so when the cloud is collapsing it can fragment in more stars because the density $\rho$ increases during this scenario, I think this is another reason why low mass stars are more common.
So my question is, are these things I mentioned the fundamental reasons why more low mass stars are generated? or there is another reason? or is what I said wrong?

**Tags:** star-formation

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## 1 answers

### Answer by username_1 on 2022-01-19. Score: 2

The crucial point here is that the initial large cloud does not have a constant density throughout but contains many random smaller blobs with a higher density. Because of the higher density, these will collapse faster than the whole cloud would. So you end up with a star cluster rather than one supermassive star.

> **Comments:**
> **username_2**: This isn't the main reason that fragmentation occurs.  
> **username_1**: @ProfRob One needs density irregularities in the first place for fragmentation to occur  
> **username_2**: The correct explanation is here https://en.m.wikipedia.org/wiki/Jeans_instability The presence of density perturbations is not sufficient to cause fragmentation. There are other conditions that are met in collapsing protostellar clouds.  
> **username_1**: @ProfRob Density irregularities as such may not be sufficient for fragmentation but they are necessary. Without them the giant cloud would just collapse as a whole towards its center.  

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