Stars Galaxies and Hr Diagrams

An astronomer observes several items in the night sky. She observes this item and graphs it's temperature and brightness. What is it?

• a planet, probably Jupiter or Saturn

• a nearby star relatively close to our solar system

• a comet

• another galaxy

Using this chart what is Object #2 most likely to be?

• Venus

• a nearby star relatively close to our solar system

• a black hole near the center of the Milky Way

• another galaxy

The Horsehead Nebula is located about 1,500 light years from Earth in the constellation Orion. What is most likely occurring in the Horsehead Nebula?

• new star formation

• formation of black holes

• star explosions like supernovas

• the birth of new galaxies

The stars we see at night are: 

• in the Milky Way galaxy
  
• in the solar system
  
• in galaxies other than the Milky Way 
• both A and C 

Use this model of the Hertzsprung-Russell diagram to answer question. 
An astronomer discovers a new star that is very hot, but not very bright. What type of star did she discover? 

• a red giant
  
• a young star on the main sequence 
• an old star on the main sequence 
• a white dwarf 

 Our Sun is a middle-aged star with an average temperature and brightness. What type of star is our Sun according to the Hertzburg-Russell diagram? 

• a white dwarf
  
• a red giant
  
• a star on the upper left portion on the main sequence 
• a star in the middle of the main sequence 

As a normal, averaged-size star progresses through its life cycle, what change will it undergo? 

• it becomes cooler
  
• it gets smaller
  
• it becomes brighter 
• its gravity increases 

Which of the following galaxies is most like our own Milky Way? 

• A
• B
• C
• D

Using the picture, which answer choice could best be classified as an irregular galaxy?

• Galaxy A

• Galaxy B

• Galaxy C

• Galaxy D

 Pulsars are dense, rotating stars that emit strong electromagnetic radiation with a wavelength around 6 mm. Using the chart below, what type of telescope would be best suited for observing pulsars? 

• radio telescopes 
• infrared telescopes 
• optical telescopes 
• ultraviolet telescopes