Apparent and Absolute Brightness

Gloria is at the observatory and is examining a newly discovered star through a powerful telescope. She wants to find out how bright the star actually is. What information does she need to calculate the absolute magnitude of a star?

• Apparent magnitude and distance from Earth of the star.
• Color and distance from Earth of the star
• Color of the star
• Color and composition of the star

The table compiles information about the distance of various stars from Earth, their apparent magnitude, and their absolute magnitude.
Which of the stars listed in the table above would look the brightest when compared to other stars from an equal distance?

• Sirius
• Betelgeuse
• Rigel
• Aldebaran

The table compiles information about the distance of various stars from Earth, their apparent magnitude, and their absolute magnitude.
Which star has the least luminosity?

• Sirius
• Rigel
• Arcturus
• Betelgeuse

The table compiles information about the distance of various stars from Earth, their apparent magnitude, and their absolute magnitude.
Which star is the closest to earth?

• Betelgeuse
• Vega
• Arcturus
• Aldebaran

How bright a star appears in the night sky relative to other stars seen there is called its

• luminosity
• spectral class
• absolute magnitude
• apparent magnitude

Betelgeuse has a very high luminosity but does not out a lot of sunlight.Which of the following explains this?

• cant be smaller then the sun
• Betelgeuse is at the lower end of the main sequence.
• Betelgeuse is at the upper end of the main sequence.
• must have a much larger surface area than the Sun.

What is Stellar Luminosity?

• Ketzia's face
• The total power a star radiates into space 
• My smile
• how much sun light a star outputs

How is Stellar Luminosity Calculated?

• Staring at the sun for as long as you can
• From a thermometer
• How many lick to the center of a tootsie pop
• From a star's measured apparent brightness and distance

An astronomer observes two stars and finds that they have the same apparent magnitude. Based on his observation, which conclusion could not be true?

• Both stars are the same distance from the Earth and emit the same amount of energy.
• One star is farther from the Earth, and emits more energy than the other one.
• Both stars have the same absolute magnitude and are the same distance from the Earth.
• One star has greater luminosity and is closer to the Earth than the other one.

The table compiles information about the distance of various stars from Earth, their apparent magnitude, and their absolute magnitude.
Which of the stars listed in the table above would look the dimmest when observed from Earth?

• Sirius
• Rigel
• Aldebaran
• Arcturus