Spectral Classes
H-R Questions
H-R Warmup Questions
Using the H-R Diagram
H-R Trends
100
What are spectral classes organized by?
Temperature
100
The coldest stars are considered to be what color?
Red
100
What is luminosity?
luminosity is apparent magnitude - the brightness of an object as it appears from earth
100
Which the dimmest?
Proxima Centauri
100
As you move towards the right of the H-R diagram, stars become....
cooler
200
What spectral class would our sun be considered a member of?
Class G
200
The hottest stars are considered to be what color?
Blue
200
What are the largest stars called?
Red Hypergiants
200
Find a star that has a higher absolute magnitude than betelgeuse
Rigel, Deneb, RW Cephei, Canopus
200
As you move down the H-R diagram, stars become...
more dim
300
What spectral classes are cooler than M?
What spectral classes are hotter than M?
Colder: None
Hotter: K,G,F,B,A,O
300
What is the name of the portion of the H-R diagram where most of the stars reside?
+100 for the percentage
Main Sequence
90%
300
If a star were to increase in absolute magnitude, what direction would the star move on the H-R diagram?
up
300
Find a star with a lower effective temperature than our sun
Barnard's Star, Proxima Centauri, Aldebaran, Mira, Antares, Betelgeuse
300
As you towards the left of the H-R diagram, what increases (only left, not up)
temperature (and mass)
400
What spectral class are white dwarfs and red giants a part of?
- If more than one, write the range
White dwarfs: type B
Red giants: M-F
400
What are the 4 variables used to plot stars on the H-R diagram?
Absolute Magnitude, Luminosity, Temperature, Spectral Class
400
There are 3 stars of equal size and equal apparent brightness, however they are located at various distances. One star is blue, one is yellow, and one is red. Order them from least to greatest based on absolute magnitude.
Red, Yellow, Blue
400
Compare the luminosity between Sirius B, The Sun, and Rigel
Sirius B is the least luminous of the 3, The sun is more luminous than Sirius B, Rigel is the most luminous of the 3
400
Stars produce energy via....
Nuclear Fusion
500
Organize the spectral classes on a line size and temperature.
The order should be O-B-A-F-G-K-M from high to low temperature and size
O- Blue
B- Whitish blue
A- White
F- Yellow white
G- Yellow
K- Orange
M- Red
500
Describe where stars move as they age?
x2 for what traits change
They move up and to the right.
They become larger, brighter, but cooler.
500
There are three stars a,b, & c located at the same distance from Earth. Star B has a high temperature and is a white star, star A is by far the biggest and is a red giant, and star C is the smallest but the hottest being a white dwarf. Order the stars based on their apparent brightness.
Star A, B, C
500
Which types of stars are the most dense, which are the least?
Most: White Dwarfs
Least: Red Hypergiants
500
As you move from bottom left corner to top right corner, what decreases?
Density