Download H-R Diagram Notes

Notes: H-R Diagrams
Name ___
__
An H-R Diagram is…
A graph of stars’ ___________________ and ________________________.
– It also shows ___________________ since color is related to temperature
– It was made by two astronomers who plotted the data for thousands of stars and noticed some
trends.
– It stands for _______________________________________________.
Notice…..
• Temperature ______________________ as you move to the Right on the X-axis
• Absolute Magnitude ________________________ as you move up on the Y-axis.
• NEGATIVE absolute magnitude values are ____________________ than POSITIVE absolute
magnitude values
A star…
• Starts off in the lower right hand corner in ___________________________ when it first becomes a
star.
• As it gets ______________ and _______________, it moves up the main sequence.
• Then it moves to upper right section when it changes to _____________________________.
• It ends in the lower left section when it changes to a _____________________________.
Questions
1. What is the relationship between temperature and brightness for a main sequence star?
2. What kinds of stars are the hottest?
3. What kinds of stars are the brightest?
4. Why do White dwarves have a low brightness when they are so hot?
5. Why do Giants have such high brightness when they are not especially hot?
6.
What is the temperature of the sun?
7. What is the absolute magnitude of the sun?