<p>You need to find a <a href="https://en.wikipedia.org/wiki/Bolometric_correction" rel="nofollow noreferrer">bolometric correction</a> from the effective temperature (this is reasonably insensitive to gravity and metallicity, which you don't know). Then convert the apparent magnitude into a bolometric magnitude and then into a flux. Then, I suppose you have to assume there is no extinction to estimate the intrinsic luminosity of the star by multiplying by <span class="math-container">$4\pi d^2$</span>.</p>
<p>From there you can approximate the star as a blackbody and use Stefan's law, your intrinsic luminosity and the given temperature to estimate a radius.</p>
<p>So to answer your question directly: no. You need to know the extinction and, to get an accurate estimate, you would need to know the type of star, its chemical composition and use a better model than a blackbody for its spectrum.</p>

CC BY-SA 4.0
2022-01-09T17:50:45.040Z
We can just use distance modulus formula if an approximation is  required I suppose
Particle king
CC BY-SA 4.0
2022-01-09T11:53:12.873Z
2022-01-09T20:30:30.103Z
2022-01-09T20:30:30.103Z
ProfRob
<p>Yes</p>
<ol>
<li>Convert Apparent magnitude into absolute magnitude using distance modulus.
2.Then use stefan law and Flux Luminosity relationship.</li>
</ol>

CC BY-SA 4.0
2022-01-09T11:28:32.457Z
2022-01-09T11:28:32.457Z
Particle king
<p>Is apparent magnitude of star, distance(in pc) and effective temperature enough to calculate its stellar radii or we need some extra information?</p>

CC BY-SA 4.0
2022-01-08T10:34:49.153Z
You’ll also need its spectral type, at the very least.
Pierre Paquette
CC BY-SA 4.0
2022-01-08T10:41:29.770Z
You don't need any additional information.
AtmosphericPrisonEscape
<luminosity><apparent-magnitude><radius>
Finding stellar radii
Particle king
# Finding stellar radii

(Asked by: username_0 on 2022-01-08)

Is apparent magnitude of star, distance(in pc) and effective temperature enough to calculate its stellar radii or we need some extra information?

**Tags:** luminosity, apparent-magnitude, radius

> **Comments:**
> **username_1**: You’ll also need its spectral type, at the very least.  
> **username_2**: You don't need any additional information.  

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## 2 answers

### Answer by username_3 on 2022-01-09. Score: 3 | Accepted answer

You need to find a [bolometric correction](https://en.wikipedia.org/wiki/Bolometric_correction) from the effective temperature (this is reasonably insensitive to gravity and metallicity, which you don't know). Then convert the apparent magnitude into a bolometric magnitude and then into a flux. Then, I suppose you have to assume there is no extinction to estimate the intrinsic luminosity of the star by multiplying by $4\pi d^2$.

From there you can approximate the star as a blackbody and use Stefan's law, your intrinsic luminosity and the given temperature to estimate a radius.

So to answer your question directly: no. You need to know the extinction and, to get an accurate estimate, you would need to know the type of star, its chemical composition and use a better model than a blackbody for its spectrum.

> **Comments:**
> **username_0**: We can just use distance modulus formula if an approximation is  required I suppose  

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### Answer by username_0 on 2022-01-09. Score: 0

Yes

1. Convert Apparent magnitude into absolute magnitude using distance modulus.
   2.Then use stefan law and Flux Luminosity relationship.


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