<p>I've learned that metallicity is a very important factor to consider when talking about a star's formation and lifecycle. That gets me wondering whether a high enough metallicity could prevent the formation of proper stars altogether. Would it happen when the metallicity is so high that the hydrogen concentration isn't high enough to initiate a self-sustaining fusion reaction?</p>

CC BY-SA 4.0
2021-08-30T18:52:13.997Z
There is no limit associated with phenomenon you suggest, it just raises the minimum mass for "starhood".
ProfRob
CC BY-SA 4.0
2021-08-30T20:06:13.853Z
Couldn't it hypothetically be so high that the mass required to initiate fusion would cause the would-be star to simply collapse into a black hole? Not that I'm saying this could ever happen.
zucculent
CC BY-SA 4.0
2021-08-30T20:18:01.143Z
No. It would rise to around half a solar mass if there were no hydrogen at all at which point the helium would burn. Or about 1 solar mass and the carbon and oxygen would burn.
ProfRob
CC BY-SA 4.0
2021-08-30T20:32:22.427Z
Sounds like the only way to keep fusion from happening at all would be if a would-be star's chemical makeup was devoid of any elements capable of exothermic fusion reactions.
zucculent
CC BY-SA 4.0
2021-08-30T21:35:36.567Z
Maybe you'd be interested in the so called "quasi-star" (or black hole star) which is powered by a compact object at their cores https://en.wikipedia.org/wiki/Quasi-star
Daddy Kropotkin
CC BY-SA 4.0
2021-08-30T22:43:00.590Z
@DaddyKropotkin I thought high metallicity would keep a quasi-star from forming.
zucculent
CC BY-SA 4.0
2021-08-31T06:55:27.820Z
Some Stars are Totally Metal: A New Mechanism Driving Dust Across Star-Forming Clouds, and Consequences for Planets, Stars, and Galaxies http://arxiv.org/abs/1406.5509
sno
<star><star-formation><metallicity>
Is there a metallicity threshold past which star formation is impossible?
zucculent
# Is there a metallicity threshold past which star formation is impossible?

(Asked by: username_0 on 2021-08-30)

I've learned that metallicity is a very important factor to consider when talking about a star's formation and lifecycle. That gets me wondering whether a high enough metallicity could prevent the formation of proper stars altogether. Would it happen when the metallicity is so high that the hydrogen concentration isn't high enough to initiate a self-sustaining fusion reaction?

**Tags:** star, star-formation, metallicity

> **Comments:**
> **username_1**: There is no limit associated with phenomenon you suggest, it just raises the minimum mass for "starhood".  
> **username_0**: Couldn't it hypothetically be so high that the mass required to initiate fusion would cause the would-be star to simply collapse into a black hole? Not that I'm saying this could ever happen.  
> **username_1**: No. It would rise to around half a solar mass if there were no hydrogen at all at which point the helium would burn. Or about 1 solar mass and the carbon and oxygen would burn.  
> **username_0**: Sounds like the only way to keep fusion from happening at all would be if a would-be star's chemical makeup was devoid of any elements capable of exothermic fusion reactions.  
> **username_2**: Maybe you'd be interested in the so called "quasi-star" (or black hole star) which is powered by a compact object at their cores https://en.wikipedia.org/wiki/Quasi-star  
> **username_0**: @DaddyKropotkin I thought high metallicity would keep a quasi-star from forming.  
> **username_3**: Some Stars are Totally Metal: A New Mechanism Driving Dust Across Star-Forming Clouds, and Consequences for Planets, Stars, and Galaxies http://arxiv.org/abs/1406.5509  

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## 0 answers

