<p>Neutron stars are not to be considered as an homogeneous object, they have different properties at different <em>layers</em> which are dependant on pressure and temperature for example. Thus in the core below some critical temperature you could have superconductant protons (or any charged baryon) thus meaning you would not find atoms, but more like a soup of <em>free</em> particles.
In conclusion I don't see how could this fall into the definition of a chemical element.</p>

<p>Reference: <a href="http://books.google.com.uy/books?id=fgj_TZ06niYC">Neutron Stars 1: Equation of State and Structure.</a> By P. Haensel, A.Y. Potekhin, D.G. </p>

CC BY-SA 3.0
2014-05-02T03:47:51.280Z
2014-05-02T03:47:51.280Z
harogaston
<p>To be considered an element, they would have to have a positively charged nucleus. They don't. The neutron star is largely neutral.</p>

<p>They would have to have a cloud of surrounding electrons. These electrons would have to share "orbitals" with other electrons around other, nearby neutron stars. That doesn't happen.</p>

<p>Finally, at these scales, gravitational interaction predominates. Even if neutron stars did have some positive charge, and did have electrons orbiting them, interaction with other neutron stars would still depend a lot on gravity.</p>

<p>Finally, even if a neutron star was charged, it's not clear whether electrons around them would actually fall into some kind of orbitals governed by quantum mechanics. QM tends to not happen at such a scale.</p>

<p>In conclusion, no, they are completely unlike atoms and their nuclei.</p>

CC BY-SA 3.0
2015-07-26T22:23:30.743Z
2015-07-26T22:23:30.743Z
Florin Andrei
<p>The 'stuff' comprising the portion of a neutron star theoretically comprised mostly of neutrons has been referred to as "neutronium" in various sources, one of which is science fiction.</p>

<p>I have always found imagining what this 'neutronium' would actually look like to be an amusing exercise.  However, attempting to define this 'stuff' as an element in and of itself is no different than performing the same attempt at categorization for an exclusive mass of protons or elections.  None of these components define atoms or elements singly.  </p>

CC BY-SA 3.0
2015-07-26T03:10:55.420Z
I like the super-fluid theory.    http://physicsworld.com/cws/article/news/2011/mar/02/neutron-star-has-superfluid-core
userLTK
CC BY-SA 3.0
2015-07-26T03:57:57.117Z
Good stuff (the link contents).  Gotta love the comment, "But Ho cautions that we can't draw any practical tips from neutron stars" too on the humorous side.
Starrdaark
CC BY-SA 3.0
2017-10-17T04:22:03.620Z
`However, attempting to define this 'stuff' as an element in and of itself is no different than performing the same attempt at categorization for an exclusive mass of protons or elections`  Oh great, now you've got me wondering about the possibility and nature of a proton star, were it somehow possible to get enough protons together for gravity to overcome Coulomb repulsion...
Michael
CC BY-SA 3.0
2017-10-17T23:20:51.930Z
@Michael: Ordinary stars are made of protons that _try to be_ that. They carry electrons with them that neutralize their Coulomb fields, so repulsion doesn't become a major problems -- but long before anything like neutron star densities are reached, it becomes energetically favorable for some of them to turn into neutrons. The energy thus released makes the star shine!
hmakholm left over Monica
CC BY-SA 3.0
2015-07-26T02:47:17.083Z
2015-07-26T02:47:17.083Z
Starrdaark
<p>Think of a neutron as a proton + electron pushed into it. Neutron stars are a lot like that; any electrons that have met a proton will be very strongly forced into forming a neutron.  This happens because an object containing very many protons and electrons has collapsed below the electron degeneracy pressure limit.  Presumably, there weren't exactly the same number of protons and electrons before the collapse; and a fraction of those particles did not find their counterparts before the collapse stopped.   It's thus quite possible that a particular neutron star has a small positive charge as a whole, and it probably contains some protons and electrons (not counting neutrons). </p>

<p>However, being composed of protons, neutrons, and electrons does not make matter an element.  Being composed of protons and neutrons does not make matter an atomic nucleus.  The forces that hold the neutron star together are unrelated to the forces that hold together an atomic nucleus, and its properties are very different, too.</p>

<p>A positively charged storm cloud might have many more protons than electrons and still not be called an "element".</p>

CC BY-SA 3.0
2017-10-19T15:06:28.497Z
2017-10-19T15:06:28.497Z
Jirka Hanika
<p>Neutron stars do contain ordinary elemental atomic nuclei very near the surface, where compression even from the powerful gravity of the neutron star is not great enough to force the combination of protons and electrons into a mass of neutrons. But the nuclei are believed to be interspersed in a sea of electrons, not segregated into individual atoms (&quot;degenerate matter&quot;). <a href="https://en.wikipedia.org/wiki/Neutron_star" rel="nofollow noreferrer">Wikipedia</a> gives some more details:</p>
<blockquote>
<p>Current models indicate that matter at the surface of a neutron star is composed of ordinary atomic nuclei crushed into a solid lattice with a sea of electrons flowing through the gaps between them. It is possible that the nuclei at the surface are iron, due to iron's high binding energy per nucleon.[1] It is also possible that heavy elements, such as iron, simply sink beneath the surface, leaving only light nuclei like helium and hydrogen.[<a href="https://doi.org/10.1070/pu1999v042n11ABEH000665" rel="nofollow noreferrer">1</a>] If the surface temperature exceeds 10^6 kelvins (as in the case of a young pulsar), the surface should be fluid instead of the solid phase that might exist in cooler neutron stars (temperature &lt;10^6 kelvins).[1]</p>
</blockquote>
<p><strong>Cited Reference</strong></p>
<ol>
<li>Beskin, Vasilii S. (1999). &quot;Radio pulsars&quot;. <em>Physics-Uspekhi</em>. <strong>42</strong> (11): 1173–1174. Bibcode:1999PhyU...42.1071B. doi:10.1070/pu1999v042n11ABEH000665. S2CID 250831196.</li>
</ol>

CC BY-SA 4.0
2023-06-13T23:34:09.607Z
2023-06-13T23:34:09.607Z
Oscar Lanzi
<p>As you go up the periodic table (more protons), the ratio of neutrons to protons steadily increases as well. Are we sure there are absolutely no protons and electrons in a neutron star, or could there be so much more neutrons that we cannot measure any protons and electrons? Perhaps then a neutron star is a nucleus of some huge element with a neutron:proton ratio higher than we can distinguish.</p>

CC BY-SA 3.0
2014-04-07T11:32:01.010Z
from what is written in wiki I guess the short answer is no, as a neutron star `contains ions, electrons and nuclei` you could probably not call the whole thing an element: http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Neutron_star_cross_section.svg/500px-Neutron_star_cross_section.svg.png
DrCopyPaste
CC BY-SA 3.0
2014-05-03T03:12:22.883Z
You should provide some reference to what is considered an element.
harogaston
<neutron-star>
Is it possible neutron stars are actual elements?
fillthinehornwithoilandgo
# Is it possible neutron stars are actual elements?

(Asked by: username_0 on 2014-04-05)

As you go up the periodic table (more protons), the ratio of neutrons to protons steadily increases as well. Are we sure there are absolutely no protons and electrons in a neutron star, or could there be so much more neutrons that we cannot measure any protons and electrons? Perhaps then a neutron star is a nucleus of some huge element with a neutron:proton ratio higher than we can distinguish.

**Tags:** neutron-star

> **Comments:**
> **username_1**: from what is written in wiki I guess the short answer is no, as a neutron star `contains ions, electrons and nuclei` you could probably not call the whole thing an element: http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Neutron_star_cross_section.svg/500px-Neutron_star_cross_section.svg.png  
> **username_2**: You should provide some reference to what is considered an element.  

---

## 5 answers

### Answer by username_3 on 2015-07-26. Score: 11

To be considered an element, they would have to have a positively charged nucleus. They don't. The neutron star is largely neutral.

They would have to have a cloud of surrounding electrons. These electrons would have to share "orbitals" with other electrons around other, nearby neutron stars. That doesn't happen.

Finally, at these scales, gravitational interaction predominates. Even if neutron stars did have some positive charge, and did have electrons orbiting them, interaction with other neutron stars would still depend a lot on gravity.

Finally, even if a neutron star was charged, it's not clear whether electrons around them would actually fall into some kind of orbitals governed by quantum mechanics. QM tends to not happen at such a scale.

In conclusion, no, they are completely unlike atoms and their nuclei.


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### Answer by username_2 on 2014-05-02. Score: 10

Neutron stars are not to be considered as an homogeneous object, they have different properties at different *layers* which are dependant on pressure and temperature for example. Thus in the core below some critical temperature you could have superconductant protons (or any charged baryon) thus meaning you would not find atoms, but more like a soup of *free* particles.
In conclusion I don't see how could this fall into the definition of a chemical element.

Reference: [Neutron Stars 1: Equation of State and Structure.](http://books.google.com.uy/books?id=fgj_TZ06niYC) By P. Haensel, A.Y. Potekhin, D.G.


---

### Answer by username_4 on 2015-07-26. Score: 3

The 'stuff' comprising the portion of a neutron star theoretically comprised mostly of neutrons has been referred to as "neutronium" in various sources, one of which is science fiction.

I have always found imagining what this 'neutronium' would actually look like to be an amusing exercise. However, attempting to define this 'stuff' as an element in and of itself is no different than performing the same attempt at categorization for an exclusive mass of protons or elections. None of these components define atoms or elements singly.

> **Comments:**
> **username_5**: I like the super-fluid theory.    http://physicsworld.com/cws/article/news/2011/mar/02/neutron-star-has-superfluid-core  
> **username_4**: Good stuff (the link contents).  Gotta love the comment, "But Ho cautions that we can't draw any practical tips from neutron stars" too on the humorous side.  
> **username_6**: `However, attempting to define this 'stuff' as an element in and of itself is no different than performing the same attempt at categorization for an exclusive mass of protons or elections`  Oh great, now you've got me wondering about the possibility and nature of a proton star, were it somehow possible to get enough protons together for gravity to overcome Coulomb repulsion...  
> **username_7**: @username_6: Ordinary stars are made of protons that _try to be_ that. They carry electrons with them that neutralize their Coulomb fields, so repulsion doesn't become a major problems -- but long before anything like neutron star densities are reached, it becomes energetically favorable for some of them to turn into neutrons. The energy thus released makes the star shine!  

---

### Answer by username_8 on 2017-10-19. Score: 2

Think of a neutron as a proton + electron pushed into it. Neutron stars are a lot like that; any electrons that have met a proton will be very strongly forced into forming a neutron. This happens because an object containing very many protons and electrons has collapsed below the electron degeneracy pressure limit. Presumably, there weren't exactly the same number of protons and electrons before the collapse; and a fraction of those particles did not find their counterparts before the collapse stopped. It's thus quite possible that a particular neutron star has a small positive charge as a whole, and it probably contains some protons and electrons (not counting neutrons).

However, being composed of protons, neutrons, and electrons does not make matter an element. Being composed of protons and neutrons does not make matter an atomic nucleus. The forces that hold the neutron star together are unrelated to the forces that hold together an atomic nucleus, and its properties are very different, too.

A positively charged storm cloud might have many more protons than electrons and still not be called an "element".


---

### Answer by username_9 on 2023-06-13. Score: 1

Neutron stars do contain ordinary elemental atomic nuclei very near the surface, where compression even from the powerful gravity of the neutron star is not great enough to force the combination of protons and electrons into a mass of neutrons. But the nuclei are believed to be interspersed in a sea of electrons, not segregated into individual atoms ("degenerate matter"). [Wikipedia](https://en.wikipedia.org/wiki/Neutron_star) gives some more details:

> Current models indicate that matter at the surface of a neutron star is composed of ordinary atomic nuclei crushed into a solid lattice with a sea of electrons flowing through the gaps between them. It is possible that the nuclei at the surface are iron, due to iron's high binding energy per nucleon.[1] It is also possible that heavy elements, such as iron, simply sink beneath the surface, leaving only light nuclei like helium and hydrogen.[[1](https://doi.org/10.1070/pu1999v042n11ABEH000665)] If the surface temperature exceeds 10^6 kelvins (as in the case of a young pulsar), the surface should be fluid instead of the solid phase that might exist in cooler neutron stars (temperature <10^6 kelvins).[1]

**Cited Reference**

1. Beskin, Vasilii S. (1999). "Radio pulsars". *Physics-Uspekhi*. **42** (11): 1173–1174. Bibcode:1999PhyU...42.1071B. doi:10.1070/pu1999v042n11ABEH000665. S2CID 250831196.


---

