<p>According to wikipedia:</p>

<blockquote>
  <p>A star is a luminous sphere of plasma held together by its own gravity</p>
</blockquote>

<p>then it goes on to say that</p>

<blockquote>
  <p>Near the end of its life, a star can also contain degenerate matter </p>
</blockquote>

<p>(see also <a href="https://en.wikipedia.org/wiki/Degenerate_matter" rel="nofollow noreferrer">nuetron degeneracy</a>).</p>

<p><a href="http://www.dictionary.com/browse/star" rel="nofollow noreferrer">http://www.dictionary.com/browse/star</a> has:</p>

<blockquote>
  <ol>
  <li>Any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night.</li>
  <li>Astronomy. any of the large, self-luminous, heavenly bodies, as the sun, Polaris, etc.".</li>
  </ol>
</blockquote>

<p>Nothing in those definitions explicitly requires fusion, though the mention of plasma seems to infer it. The quantum mechanical effects in a nuetron star are an analogue to an ideal gas in classical physics. The degeneracy pressure thereof prevents the star from collapsing into a black hole.</p>

CC BY-SA 3.0
2017-10-19T13:42:02.913Z
I would argue that those definitions are not great technical definitions because a star is defined as becoming a star once it begins hydrogen fusion. Before that point, it may be called a proto-star, but it isn't a star, despite meeting the requirements in your definition.
zephyr
CC BY-SA 3.0
2017-10-19T17:52:03.803Z
I agree, but they were the only definitions I could find at 5am in the morning.  Let's try to fix that at wikipedia.
jwdonahue
CC BY-SA 3.0
2017-10-19T12:17:52.567Z
2017-10-19T12:17:52.567Z
jwdonahue
<p>I am wondering since neutron star is smaller than the average main-sequence stars and it doesn't produce energy via fusion so why do we still call it a star?</p>

CC BY-SA 3.0
2017-10-19T02:55:47.893Z
https://en.wikipedia.org/wiki/Compact_star
userLTK
<neutron-star>
Why is neutron star a star?
user6760
# Why is neutron star a star?

(Asked by: username_0 on 2017-10-19)

I am wondering since neutron star is smaller than the average main-sequence stars and it doesn't produce energy via fusion so why do we still call it a star?

**Tags:** neutron-star
> **Comments:**
> **username_1**: https://en.wikipedia.org/wiki/Compact_star  

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## 1 answers

### Answer by username_2 on 2017-10-19. Score: 2

According to wikipedia:

> A star is a luminous sphere of plasma held together by its own gravity

then it goes on to say that

> Near the end of its life, a star can also contain degenerate matter

(see also [nuetron degeneracy](https://en.wikipedia.org/wiki/Degenerate_matter)).

<http://www.dictionary.com/browse/star> has:

> 1. Any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night.
> 2. Astronomy. any of the large, self-luminous, heavenly bodies, as the sun, Polaris, etc.".

Nothing in those definitions explicitly requires fusion, though the mention of plasma seems to infer it. The quantum mechanical effects in a nuetron star are an analogue to an ideal gas in classical physics. The degeneracy pressure thereof prevents the star from collapsing into a black hole.

> **Comments:**
> **username_3**: I would argue that those definitions are not great technical definitions because a star is defined as becoming a star once it begins hydrogen fusion. Before that point, it may be called a proto-star, but it isn't a star, despite meeting the requirements in your definition.  
> **username_2**: I agree, but they were the only definitions I could find at 5am in the morning.  Let's try to fix that at wikipedia.  

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