General Astronomy Quiz 12 Flashcards
Why do astronomers observe thousands of stars?
To study their life cycle, they grow old and then die
How can you determine what class a star is and where it appears on an HR diagram?
-Plot a graph of the luminosity of different classes of a star
-Examine the light from a star (spectra)
Are all stars the same?
NO
What is the Hertzsprung-Russell Diagram?
A tool that shows stars of different ages, in different stages, at the same time
What do the background colors on the HR diagram mean?
It relates to the color of the star and its temperature
What is a star represented by in the HR?
A dot
What does the position of each dot tell us?
- Luminosity (Absolute magnitude, vertical axis)
- Temperature (horizontal axis)
Where are hot and bright stars?
Upper left corner
Where are cool and bright stars?
Upper right corner
Where is the Sun located on the HR?
In the middle (star used for comparison)
Where are hot and dim stars?
Lower left corner
Where are cool and dim stars?
Lower right corner
What is the main sequence?
-Represents the longest and most stable phases of a stars life
-Stars fuse hydrogen into helium in their cores (nuclear fusion)
What do we know about brightness and temperature?
Hotter things are brighter
What do we know about brightness and size?
Bigger stars are brighter
What is luminosity?
The amount of energy a star radiates or how bright it appears
