<p><a href="https://en.wikipedia.org/wiki/Stellar_density" rel="noreferrer">Wikipedia, quoting Erik Gregersen</a>. <em>The Milky Way and beyond.</em> gives a local value of 0.004 stars per cubic light year, or 0.14 stars per cubic parsec. </p>

<p>So within <em>n</em> light years you would expect $0.004\times 4\pi n^3/3\approx 0.016n^3$ stars.</p>

<p>This predicts the nearest star to be about 4 light-years away, consistent with observation.</p>

CC BY-SA 3.0
2017-12-16T22:07:48.667Z
2017-12-16T22:07:48.667Z
James K
<p>The nearby stars seem homogenously spaced out enough to give a general "stellar density."<br>
Does there exist some kind of mathematical expression that can determine the number of stars n light-years from the sun?<br>
Or—<br>
Is there a rough value for this supposed stellar density idea? (Ex: 0.3 stars per cubic light-year.)</p>

CC BY-SA 3.0
2017-12-17T11:02:31.113Z
Likely you need some strong assumption. Locally it works.
Alchimista
<distances><terminology>
Finding the number of stars n light-years from the sun
BenjaminF
# Finding the number of stars n light-years from the sun

(Asked by: username_0 on 2017-12-16)

The nearby stars seem homogenously spaced out enough to give a general "stellar density."  
Does there exist some kind of mathematical expression that can determine the number of stars n light-years from the sun?  
Or—  
Is there a rough value for this supposed stellar density idea? (Ex: 0.3 stars per cubic light-year.)

**Tags:** distances, terminology
> **Comments:**
> **username_1**: Likely you need some strong assumption. Locally it works.  

---

## 1 answers

### Answer by username_2 on 2017-12-16. Score: 5 | Accepted answer

[Wikipedia, quoting Erik Gregersen](https://en.wikipedia.org/wiki/Stellar_density). *The Milky Way and beyond.* gives a local value of 0.004 stars per cubic light year, or 0.14 stars per cubic parsec.

So within *n* light years you would expect $0.004\times 4\pi n^3/3\approx 0.016n^3$ stars.

This predicts the nearest star to be about 4 light-years away, consistent with observation.


---

