<p>To achieve thermonuclear fusion you need high temperatures and high density.  If you were able (by magic) to compress and heat the core of Jupiter then fusion would occur.</p>
<p>But there is no mechanism that can cause Jupiter to increase it's temperature and density like this. In the core of a proto-star, gravity will provide the force needed to increase the pressure and density and the release of gravitational energy will provide the temperature to allow fusion to start.</p>
<p>Moreover, when fusion does start, the release of energy causes the core to stop contracting and prevents the density from continuing to increase.  The release of fusion energy stabalises the collapse of the ball of gas, and allows stars to shine for perhaps billions of years.  If you started fusion in the core of Jupiter (for example by setting off a nuclear bomb) it would cause that part of core to expand, lowering density and ending the fusion.  The stable state for a body the size of Jupiter is to be a planet, not a star.</p>
<p>Increasing density by changing the composition to one with larger nuclei actually makes it harder to start fusion.  Larger nuclei have a larger positive charge. This makes it harder to get them to fuse. So you need much higher temperatures.</p>
<p>So the only way for Jupiter to become a star is to increase it's core temperature and density. But that can't happen except by greatly increasing its size.</p>

CC BY-SA 4.0
2021-03-26T15:59:48.737Z
Without sustained external pressure, the fusion will lead to an expansion to its original size and density because that is the stable situation.
Hartmut Braun
CC BY-SA 4.0
2021-03-26T16:25:04.983Z
@JamesK Yes, That is logical, Gravity and heat is basically the only astronomically way to sustain a celestial's body or star's density
Tardy
CC BY-SA 4.0
2021-03-26T16:29:34.393Z
I think if you increase jupiter's density 80 times you get a star
Tardy
CC BY-SA 4.0
2021-03-26T17:08:03.110Z
No, you don't because its not hot enough. And if you do make it hot enough and dense enough, the release of energy will rapidly cause it to expand, stop fusing, and cool.
James K
CC BY-SA 4.0
2021-03-26T21:53:27.687Z
@JamesK But, The action of increasing density can increase heat, I already know it is not sustainable to increase density without gravity.
Tardy
CC BY-SA 4.0
2021-03-31T00:10:27.030Z
So is the only other stable state of Jupiter achievable by compression a black hole?
cuckoo
CC BY-SA 4.0
2021-03-31T07:26:02.560Z
Yes, a black hole would be stable, but it would be a lot smaller,  a little under 3 meter radius.  That kind of size is not "achievable" by compression.
James K
CC BY-SA 4.0
2021-03-26T15:57:53.830Z
2021-03-26T17:14:49.840Z
2021-03-26T17:14:49.840Z
James K
<p>The minimum mass for a brown dwarf is about 12-13 jupiter masses, and averagely they're 75, so theres no chance that Jupiter would be a star at its current weight.</p>

CC BY-SA 4.0
2021-03-27T00:44:24.943Z
Yes cheers fixed the mistake.
bandybabboon
CC BY-SA 4.0
2021-03-27T00:05:47.193Z
2021-03-27T00:43:43.063Z
2021-03-27T00:43:43.063Z
bandybabboon
<p>Astronomers or Scientists say that Jupiter's Mass would have to be multiplied 80 times to become a star (M Mass). What if Jupiter was denser, would there be thermonuclear energy because of the density?</p>

CC BY-SA 4.0
2021-03-26T16:09:37.917Z
How are you making Jupiter more dense? Are you replacing some of its hydrogen & helium with denser elements, eg iron?
PM 2Ring
CC BY-SA 4.0
2021-03-26T16:22:10.727Z
@PM2Ring Sure, Iron would do
Tardy
CC BY-SA 4.0
2021-03-26T16:26:22.797Z
But keeping most of the helium and hydrogen is necessary for thermonuclear reactions so let's just say we can make it denser by magic and temps
Tardy
CC BY-SA 4.0
2021-03-26T16:34:41.563Z
Jupiter has a lot of H & He. Even if you replaced half of it, there'd still be plenty left. ;) A planet like that's unlikely to form naturally, but at least we could answer your question using science. It's tricky to give scientific answers to questions that invoke magic.
PM 2Ring
<jupiter>
If jupiter was the densest planet on the solar system with low volume, could it be a star without multiplying its mass 80 times?
Tardy
# If jupiter was the densest planet on the solar system with low volume, could it be a star without multiplying its mass 80 times?

(Asked by: username_0 on 2021-03-26)

Astronomers or Scientists say that Jupiter's Mass would have to be multiplied 80 times to become a star (M Mass). What if Jupiter was denser, would there be thermonuclear energy because of the density?

**Tags:** jupiter

> **Comments:**
> **username_1**: How are you making Jupiter more dense? Are you replacing some of its hydrogen & helium with denser elements, eg iron?  
> **username_0**: @PM2Ring Sure, Iron would do  
> **username_0**: But keeping most of the helium and hydrogen is necessary for thermonuclear reactions so let's just say we can make it denser by magic and temps  
> **username_1**: Jupiter has a lot of H & He. Even if you replaced half of it, there'd still be plenty left. ;) A planet like that's unlikely to form naturally, but at least we could answer your question using science. It's tricky to give scientific answers to questions that invoke magic.  

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## 2 answers

### Answer by username_2 on 2021-03-26. Score: 1 | Accepted answer

To achieve thermonuclear fusion you need high temperatures and high density. If you were able (by magic) to compress and heat the core of Jupiter then fusion would occur.

But there is no mechanism that can cause Jupiter to increase it's temperature and density like this. In the core of a proto-star, gravity will provide the force needed to increase the pressure and density and the release of gravitational energy will provide the temperature to allow fusion to start.

Moreover, when fusion does start, the release of energy causes the core to stop contracting and prevents the density from continuing to increase. The release of fusion energy stabalises the collapse of the ball of gas, and allows stars to shine for perhaps billions of years. If you started fusion in the core of Jupiter (for example by setting off a nuclear bomb) it would cause that part of core to expand, lowering density and ending the fusion. The stable state for a body the size of Jupiter is to be a planet, not a star.

Increasing density by changing the composition to one with larger nuclei actually makes it harder to start fusion. Larger nuclei have a larger positive charge. This makes it harder to get them to fuse. So you need much higher temperatures.

So the only way for Jupiter to become a star is to increase it's core temperature and density. But that can't happen except by greatly increasing its size.

> **Comments:**
> **username_3**: Without sustained external pressure, the fusion will lead to an expansion to its original size and density because that is the stable situation.  
> **username_0**: @JamesK Yes, That is logical, Gravity and heat is basically the only astronomically way to sustain a celestial's body or star's density  
> **username_0**: I think if you increase jupiter's density 80 times you get a star  
> **username_2**: No, you don't because its not hot enough. And if you do make it hot enough and dense enough, the release of energy will rapidly cause it to expand, stop fusing, and cool.  
> **username_0**: @JamesK But, The action of increasing density can increase heat, I already know it is not sustainable to increase density without gravity.  
> **username_4**: So is the only other stable state of Jupiter achievable by compression a black hole?  
> **username_2**: Yes, a black hole would be stable, but it would be a lot smaller,  a little under 3 meter radius.  That kind of size is not "achievable" by compression.  

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### Answer by username_5 on 2021-03-27. Score: 0

The minimum mass for a brown dwarf is about 12-13 jupiter masses, and averagely they're 75, so theres no chance that Jupiter would be a star at its current weight.

> **Comments:**
> **username_5**: Yes cheers fixed the mistake.  

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