Mass of Sun/stars (elemental/molecular vs. plasma)

In summary: The electrons do not need to be stripped from the nuclei - a neutral gas that is heated above ~5000K will become a plasma, even though the nuclei are not stripped of their electrons. In summary, the Sun and stars in general are nearly perfect spheres of hot plasma, with about three quarters of the Sun's mass consisting of hydrogen and the rest mostly helium. Plasma is comprised of elements, specifically their bare nuclei and electrons, making it a soup of particles in the fourth state of matter. In the case of the Sun, it is mostly hydrogen plasma, with free-floating protons in a sea of electrons, followed by 2 protons and 2 neutrons nuclei in the same sea of electrons. This configuration is considered elemental hydrogen.
  • #1
hollowman
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I'm confused about the mass of the Sun (and stars in general).
https://en.wikipedia.org/wiki/Sun
Wikipedia notes:
" It is a nearly perfect sphere of hot plasma..."
...and later ...
"About three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), ..."

I thought that plasma was not comprised of elements (much less molecules); rather, it's a soup of particles in that fourth state of matter.
Correct me if I'm off, of course.
So how can the Sun be mostly H/He (mass) and hot plasma?
-------------
I asked the above on another forum, and a reply was:

"The atomic nuclei retain their identities, which is what gives the elemental abundances quoted."

To which I replied:
Wiki also notes:
"In a plasma, electrons are ripped away from their nuclei, forming an electron "sea". This gives it the ability to conduct electricity."
I can buy that ...except the fact that (for H, 75% of Sun's mass) you've got single protons floatin' 'round in a sea of electrons. Not sure what nuclear identities can be made out from that confused mess, unless you're further dividing the proton's HYDROGEN identity to its quark-based substructure.
To which another member replied:
"The nuclear identity of a proton is simply "hydrogen". No need to bring quarks into it, an isolated proton and a hydrogen nucleus are just the same thing."
------
So what is plasma in the Sun? E.g., ist it simply 75% Hydrogen as free-floating protons in a sea of electrons ... followed by 2P/2N nuclei in that same sea of electrons ... etc.?

If I have single protons in a sea of electrons (but not in orbit around the proton), is that configuration elemental hydrogen?

Thanks!
 
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  • #2
hollowman said:
I thought that plasma was not comprised of elements (much less molecules); rather, it's a soup of particles in that fourth state of matter.
Plasma IS comprised of elements - specifically their bare nuclei + electrons. Those are the particles making up the soup.
hollowman said:
ist it simply 75% Hydrogen as free-floating protons in a sea of electrons ... followed by 2P/2N nuclei in that same sea of electrons ... etc.?
Yes.
hollowman said:
If I have single protons in a sea of electrons (but not in orbit around the proton), is that configuration elemental hydrogen?
Yes. It's hydrogen plasma.
 
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  • #3
Bandersnatch said:
Plasma IS comprised of elements - specifically their bare nuclei + electrons. Those are the particles making up the soup. Yes. It's hydrogen plasma.
Thx!
I think Wiki (and other physics references) should use compound phrases like "hydrogen plasma" and/or be more clear when it comes to defining the elemental phases of matter.
 
  • #4
hollowman said:
I think Wiki (and other physics references)
Wikipedia is not a physics reference.
 
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  • #5
hollowman said:
Thx!
I think Wiki (and other physics references) should use compound phrases like "hydrogen plasma" and/or be more clear when it comes to defining the elemental phases of matter.
Why? "Solid" is a state of matter, you don't have to list "iron solid, sodium solid, chromium solid, gold solid, ...". You can talk about solid gold if you want to look at this element in particular, but that is not the general concept of a solid any more - it is more specific. Same for plasma: You can make many general statements about plasma, but if you want to look at one particular instance (like the sun) you can be more specific: "hydrogen/helium plasma".
 
  • #6
Is plasma, like hydrogen plasma in the Sun, ionized? Ionized by one of the word's definitions (i.e., loss of an electron)?
 
  • #7
The atoms in a plasma are ionized - at least enough of them to have many electrons and ions. That is the definition of a plasma.
 

What is the mass of the sun?

The mass of the sun is approximately 2 x 10^30 kilograms, or about 333,000 times the mass of the Earth.

How does the mass of a star affect its lifecycle?

The mass of a star determines its size, temperature, and luminosity, which in turn affects its lifespan and its ultimate fate (whether it will become a white dwarf, neutron star, or black hole).

What is the difference between elemental/molecular mass and plasma mass in stars?

Elemental/molecular mass refers to the combined mass of all the atoms and molecules that make up a star, while plasma mass refers to the mass of the electrically charged particles (ions and electrons) that make up the plasma in a star's core.

How is the mass of a star measured?

The mass of a star can be measured by observing its gravitational effects on other objects (such as its orbiting planets), or by analyzing its spectral lines to determine its temperature and luminosity, which can then be used to estimate its mass using stellar models.

Can the mass of a star change over time?

Yes, the mass of a star can change over time due to processes such as nuclear fusion, mass loss through stellar winds, or accretion of material from a companion star. However, these changes are very slow and have a minimal impact on the overall mass of the star.

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