HR diagrams

Question 1

spectral class types and their colors

Answer 1

O, B, A, F, G, K, M
blue, light blue, white-blue, white, yellow, orange, red respectively

Question 2

temperature + main sequence lifetime of O + B spectral types

Answer 2

O
- temp: 30, 000+
- 1 - 10 Myrs
B
- temp: 10,000 - 30,000
- 11 - 400 Myrs

Question 3

temperature + main sequence lifetime of A + F spectral types

Answer 3

A
- temp: 7,500 - 10,000
- 440 Myrs - 3 Gyrs
F
- temp: 6,000 - 7,500
- 3 - 7 Gyrs

Question 4

temperature + main sequence lifetime of G + K spectral types

Answer 4

G
- temp: 5,000 - 6,000
- 8 - 15 Gyrs
K
- temp: 3,500 - 5,000
- 17 Gyrs

Question 5

temperature + main sequence lifetime of M spectral type

Answer 5

• temp: 2,500 - 3,500
• 56 Gyrs

Question 6

why do stars look different

Answer 6

as an object becomes hotter it emits more energy per second = area under the curve. It also emits more short wave(high frequency) radiation. The colour is how the mix of emitted wavelengths appears to our eyes.

Question 7

luminosity meaning

Answer 7

the amount of energy emitted per second by the surface of a star

Question 8

brightness vs luminosity

Answer 8

brightness depends on luminosity + distance

Question 9

luminosity vs radius

Answer 9

L = R^2

Question 10

luminosity vs temperature

Answer 10

L = T^4

Question 11

luminosity vs radius + temperature

Answer 11

L = R^2 x T^4