Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Europan Ocean on 15/09/2013 13:01:10

Title: Can a massive ball of water become a star?
Post by: Europan Ocean on 15/09/2013 13:01:10
In deep space, if a ball of pure water formed that was one hundred times more heavy than Jupiter would it compress and form a star?
Title: Re: Can a massive ball of water become a star?
Post by: Bored chemist on 15/09/2013 14:36:52
A hundred times more mass than Jupiter would still be about 10 times less than the sun so I doubt it would get hot enough to start fusion- especially with the oxygen getting in the way.
But with enough water I think you would get a rather odd star.
Title: Re: Can a massive ball of water become a star?
Post by: Pmb on 15/09/2013 16:21:21
Quote from: Bored chemist on 15/09/2013 14:36:52
A hundred times more mass than Jupiter would still be about 10 times less than the sun so I doubt it would get hot enough to start fusion- especially with the oxygen getting in the way.
But with enough water I think you would get a rather odd star.
No. The nuclei in the water is not correct to form a self sustained chain fusioon reaction.
Title: Re: Can a massive ball of water become a star?
Post by: Bored chemist on 15/09/2013 16:22:51
Most of the nuclei in water are hydrogen and that makes stars perfectly well.
How would the oxygens stop it?
Title: Re: Can a massive ball of water become a star?
Post by: Pmb on 15/09/2013 16:48:58
Quote from: Bored chemist
Most of the nuclei in water are hydrogen and that makes stars perfectly well.
That is correct. However the reaction wouldn't be self-sustained. The reaction cross section would be too small.

Quote from: Bored chemist
How would the oxygens stop it?
I've changed my mind on this. I shouldn't have spoken about things I don't know about and the lifetime and processes in stars is something I don't know about, at least for now.

I'd rather be known for talking about those things that I'm knowledgeable about rather than talking about things that I don't know about. Stellar lifetimes are something that I don't know about, at least for now. :)
Title: Re: Can a massive ball of water become a star?
Post by: Bored chemist on 15/09/2013 19:14:45
In principle, you could have a star that "burned" just oxygen. The fusion to higher mas nuclei would be energetically favoured.
Title: Re: Can a massive ball of water become a star?
Post by: Pmb on 15/09/2013 19:32:45
Quote from: Bored chemist on 15/09/2013 19:14:45
In principle, you could have a star that "burned" just oxygen. The fusion to higher mas nuclei would be energetically favoured.
Yeah. I realized that. That's why I realized I should just be quite and be thought ignorant rather than open my mouth and prove it! :D
Title: Re: Can a massive ball of water become a star?
Post by: CliffordK on 15/09/2013 20:53:07
As the core of the star heated up, the oxygen/hydrogen bonds would naturally break and one would get free hydrogen & oxygen plasma (not really water anymore).

Would the oxygen plasma be of a greater density than the hydrogen plasma, and thus tend to stratify somewhat?