Introduced to H-R Diagrams

Which of the following is not an accepted use of an H-R diagram?

• Visual way to “graph” and categorize stars based on their characteristics
• Allows astronomers to recognize patterns in types of stars
• Allows us to track the life cycle of stars as they change over time
• Allows us to determine the distance of stars with great accuracy

Absolute magnitude is defined as...

• the brightness of an object in space, measured as if you’re 10 parsecs away from the object.
• Total energy emitted by a space object per unit time.
• the brightness of an object in space, as it appears from Earth
• the color of an object in space, described on a number scale.

If an object has a luminosity of 7.5, this means...

• the object is 7.5 times brighter than the sun.
• the object is 7.5% brighter than the sun
• the object has a redder color than the sun.
• the object is 7.5 times smaller than the sun.

The effective temperature of a star is related to its...

• solar system
• luminosity
• absolute magnitude
• color

Spectral class is a way of describing a star’s

• size
• luminosity
• age
• color

The color index of a star provides information about that star’s

• age
• luminosity
• absolute magnitude
• temperature

An open cluster has ___________ stars.

• less than 100
• more than 100,000
• less than 50
• more than 500

A globular cluster has ___________ stars.

• less than 100
• more than 100,000
• less than 50
• more than 500

This is an H-R Diagram of a star cluster.  Which of the following is true about the stars in Area 1 (bound by the red box)

• These stars are red giants.
• These stars are white dwarfs.
• These stars are main sequence stars.
• These stars are in the first half of their life span.

This is an H-R Diagram of a star cluster.  The stars that are not in Area 1 or Area 2 are part of the...

• main sequence
• white dwarf group
• blue giant group
• instability strip