<p>Luminosity is the total energy output of a star per unit time. For example, our own Sun has a luminosity of $3.828\times 10^{26}\ \mathrm{Joules/second}$. Our Sun outputs more energy in a single second than <a href="https://en.wikipedia.org/wiki/Electric_energy_consumption" rel="nofollow noreferrer">the entire world consumes in a year</a>.</p>

<p>The absolute magnitude is, in some ways, analogous to luminosity in that it is a measure of the energy output of a star. The definition of absolute magnitude is that it is the magnitude a star would have if it were 10 parsecs from an observer. Obviously understanding this definition requires understanding the <a href="https://en.wikipedia.org/wiki/Apparent_magnitude" rel="nofollow noreferrer">magnitude system</a>, which is outside the scope of the question and I will not be explaining it here.</p>

CC BY-SA 3.0
2018-03-22T11:46:01.813Z
2018-03-22T11:46:01.813Z
zephyr
<p>I am writing a one page essay front and back about the H-R diagram, I am supposed to describe what is on it and how we use them. But I don't know the difference between luminosity and absolute magnitude.</p>

CC BY-SA 3.0
2018-03-22T05:43:19.790Z
You should start by looking up what "Luminosity" and "Absolute Magnitude" are. Stack Exchange is a place to come for answers after you have already done some research and tried your best to figure out the answer.
Phiteros
CC BY-SA 3.0
2018-03-22T19:11:38.637Z
Google is a good friend. You can ask it, and it will direct you to Wikipedia which is very helpful.
Jaideep Khare
<the-sun>
What is the difference between luminosity and absolute magnitude?
Jose Jimenez
# What is the difference between luminosity and absolute magnitude?

(Asked by: username_0 on 2018-03-22)

I am writing a one page essay front and back about the H-R diagram, I am supposed to describe what is on it and how we use them. But I don't know the difference between luminosity and absolute magnitude.

**Tags:** the-sun

> **Comments:**
> **username_1**: You should start by looking up what "Luminosity" and "Absolute Magnitude" are. Stack Exchange is a place to come for answers after you have already done some research and tried your best to figure out the answer.  
> **username_2**: Google is a good friend. You can ask it, and it will direct you to Wikipedia which is very helpful.  

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## 1 answers

### Answer by username_3 on 2018-03-22. Score: 2

Luminosity is the total energy output of a star per unit time. For example, our own Sun has a luminosity of $3.828\times 10^{26}\ \mathrm{Joules/second}$. Our Sun outputs more energy in a single second than [the entire world consumes in a year](https://en.wikipedia.org/wiki/Electric_energy_consumption).

The absolute magnitude is, in some ways, analogous to luminosity in that it is a measure of the energy output of a star. The definition of absolute magnitude is that it is the magnitude a star would have if it were 10 parsecs from an observer. Obviously understanding this definition requires understanding the [magnitude system](https://en.wikipedia.org/wiki/Apparent_magnitude), which is outside the scope of the question and I will not be explaining it here.


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