Astronomy Final: Chapters 9 & 10

Question 1

What is absolute brightness?

Answer 1

The amount of light seen from 10 parsecs away

Question 2

What is absolute magnitude?

Answer 2

The brightness seen from 10 parsecs away

Question 3

What is apparent brightness?

Answer 3

The amount of light from a star that reaches Earth

Question 4

What is apparent magnitude?

Answer 4

The amount of brightness as it is actually measured on Earth

Question 5

What is an HR Diagram?

Answer 5

Shows the relationship between magnitudes / luminosities versus stellar classifications / temperatures

Question 6

What are radius lines?

Answer 6

Straight lines rising to the left w/ a slope of 4 which separate by factors of 100

Question 7

What are the spectral classes?

Answer 7

O, B, A, F, G, K, & M

Question 8

What is luminosity?

Answer 8

The total energy a star radiates in 1 second

Question 9

Spectral Classes Characteristics:

Answer 9

-Decreasing mass
-Increasing lifetimes
-O is rare; M is common (main sequence)

Question 10

What is the interstellar medium?

Answer 10

The matter & radiation that exist in space between star systems in a galaxy (includes gas & dust)

Question 11

What does the interstellar medium create?

Answer 11

Creates new stars

Question 12

What is a reflection nebula?

Answer 12

Clouds of interstellar dust which might reflect the light of a nearby star whose insufficient to ionize the gas of a nebula but sufficient enough to scatter dust to become visible

Question 13

What is an emission nebula?

Answer 13

Ionized gases that emit light of various wavelengths