You can Compare Brightness using Absolute Magnitude Flashcards
What does a stars brightness depend on?
It’s size and temp
In general, the bigger and hotter the star…
The brighter it is
The closer the star…
The brighter it appears
Why can classifying stars by brightness be difficult?
The brightness they appear from Earth also depends on their distance from Earth
How do we deal with this?
By using a value called ‘absolute magnitude’
What is absolute magnitude a measure of?
How bright a given star would appear of be if it was a fixed distance from Earth (around 3.1 x 10 to the power of 17 m)
What does absolute magnitude allow us to do?
Compare the brightness of stars without having to worry about their relative distances from a earth
The lower the absolute magnitude…
The brighter the star
What is the value like for very bright stars for their absolute magnitude?
Negative
