<p>Wikipedia quotes $0.1542\pm 0.0045$ solar radii which is $107276\,km$ with an error of about $3130\, km$.</p>

<p>They also give a reference to a 2017 paper available on Arxiv <a href="https://arxiv.org/abs/1611.03495" rel="nofollow noreferrer"><em>Proxima's orbit around Alpha Centauri</em>, P. Kervella, F. Thévenin, C. Lovis</a> that gives this value.</p>

<p>Wolfram's estimate is too far off to be an experimental error, IMO, and I think someone has just inadvertently used the diameter (twice the radius) rather than the radius.</p>

CC BY-SA 3.0
2018-02-23T08:42:29.130Z
2018-02-23T08:42:29.130Z
StephenG - Help Ukraine
<p>I was looking up the radius of Proxima Centauri and got a funny result.</p>

<p>Google says it's about 100,000 km, while WolframAlpha says its about 200,000 km.  Are the error bars that big, or does someone have some bad numbers?</p>

CC BY-SA 3.0
2018-02-23T08:03:12.233Z
I had not realised either were in the business of measuring stellar radii. Were no original sources quoted?
ProfRob
<size>
Inconsistent online radius value for Proxima Centauri
David Elm
# Inconsistent online radius value for Proxima Centauri

(Asked by: username_0 on 2018-02-23)

I was looking up the radius of Proxima Centauri and got a funny result.

Google says it's about 100,000 km, while WolframAlpha says its about 200,000 km. Are the error bars that big, or does someone have some bad numbers?

**Tags:** size
> **Comments:**
> **username_1**: I had not realised either were in the business of measuring stellar radii. Were no original sources quoted?  

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## 1 answers

### Answer by username_2 on 2018-02-23. Score: 3 | Accepted answer

Wikipedia quotes $0.1542\pm 0.0045$ solar radii which is $107276\,km$ with an error of about $3130\, km$.

They also give a reference to a 2017 paper available on Arxiv [*Proxima's orbit around Alpha Centauri*, P. Kervella, F. Thévenin, C. Lovis](https://arxiv.org/abs/1611.03495) that gives this value.

Wolfram's estimate is too far off to be an experimental error, IMO, and I think someone has just inadvertently used the diameter (twice the radius) rather than the radius.


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