<p>You'd need to know the distance to the star first (which you can get using the <a href="https://en.wikipedia.org/wiki/Cosmic_distance_ladder" rel="nofollow noreferrer">distance ladder</a>). From there, you can infer the <a href="https://en.wikipedia.org/wiki/Luminosity_distance" rel="nofollow noreferrer">luminosity distance</a>, and then use the flux you measure to calculate the luminosity using the flux-distance relationship.</p>

CC BY-SA 4.0
2023-09-12T14:21:32.390Z
This an incomplete answer, since in general, a broadband magnitude does not give you the bolometric flux.
ProfRob
CC BY-SA 4.0
2023-09-12T14:52:58.670Z
@ProfRob you almost surely know more about this corner of astronomy than me, so you should write an answer =)
Allure
CC BY-SA 4.0
2023-09-04T02:06:16.240Z
2023-09-04T02:06:16.240Z
Allure
<p>I was wondering if there's a way to calculate a star's luminosity from apparent magnitude data.</p>

CC BY-SA 4.0
2023-09-03T21:41:49.473Z
You see a distant light. You know it's a light bulb. Can you tell how many watts it has? You know what a 100W lamp looks from 1m distance What do you need to know to be able to determine the power or absolute brightness (=luminosity) of the distant lamp?
planetmaker
<luminosity><apparent-magnitude>
Is there a way to calculate a star's luminosity from its apparent magnitude?
Nam
# Is there a way to calculate a star's luminosity from its apparent magnitude?

(Asked by: username_0 on 2023-09-03)

I was wondering if there's a way to calculate a star's luminosity from apparent magnitude data.

**Tags:** luminosity, apparent-magnitude

> **Comments:**
> **username_1**: You see a distant light. You know it's a light bulb. Can you tell how many watts it has? You know what a 100W lamp looks from 1m distance What do you need to know to be able to determine the power or absolute brightness (=luminosity) of the distant lamp?  

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## 1 answers

### Answer by username_2 on 2023-09-04. Score: 4 | Accepted answer

You'd need to know the distance to the star first (which you can get using the [distance ladder](https://en.wikipedia.org/wiki/Cosmic_distance_ladder)). From there, you can infer the [luminosity distance](https://en.wikipedia.org/wiki/Luminosity_distance), and then use the flux you measure to calculate the luminosity using the flux-distance relationship.

> **Comments:**
> **username_3**: This an incomplete answer, since in general, a broadband magnitude does not give you the bolometric flux.  
> **username_2**: @username_3 you almost surely know more about this corner of astronomy than me, so you should write an answer =)  

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