1. Stars

• Stars are composed of mostly what?

  Hydrogen and Helium
• The Sun is the only ____ in our solar system.

  Star
• How do stars produce energy?

  Nuclear fusion
• What is nuclear fusion?

  the process where multiple atomic nuclei combine

  
• What are the characteristics of stars?

  Color and Temperature, Size, Mass, Brightness
• What do the color of stars indicate?

  Their surface temperature
• Stars with lower temperatures are?

  red in color
• Stars with higher temperatures are?

  blue in color
• Stars can also be described in combinations of colors
• Stars are more accurately classified based on?

  Spectral types
• What are spectral types?

  temperature measurements based on the absorbed elements
• What are the spectral types?

  Orange, Blossoms, Are, Fragrant, Giving, Kind, Memories
• Size is measured based on?

  the suns radius
• larger than the sun:

  giant, supergiant, or hypergiant stars
• What stars are same as the suns?

  medium stars
• what is a dwarf star?


  smaller than the sun
• What is mass?

  indicates the elements produced during nuclear reactions
• What stars fuse H atoms to form He?


  small to medium stars
• What stars fuse more elements to form new ones?

  large mass stars
• What is the mass of the sun?

  1.989 x 10^30 kg
• What is brightness?

  Dependent on its size and temperature
• What are the two types of brightness?

  1. Absolute Brightness
  2. Apparent Brightness
• What is apparent brightness a.k.a apparent magnitude (m)


  may vary based on location
• Apparent brightness

  the lower the value, the brighter the object (negative values indicate extreme apparent brightness)
• What is absolute brightness a.k.a absolute magnitude (M)


  depends on its true brightness
• What is the unit for distance for stars? (distance traveled by light in a year)

  Light-year = 9.5 x 10^12 km
• Absolute brightness is related to the stars?

  Luminosity
• What is Luminosity?

  the total amount of energy radiated by the star per second
• When fuels for nuclear fusions run out stars are predicted to?

  Die
• Who plotted star luminosities against their colors? Year : 1911


  Ejnar Hertzsprung
• who plotted star luminosities against their spectral types? Year : 1913 


  Henry Norris Russell
• What is the H-R Diagram?

  a graph of stars showing the relationship of a stars magnitude or luminosity against their stellar classification
• What is the standard in describing other stars in the universe?

  Sun
• What are the two parts in H-R diagram?

  1. Solar mass
  2. Solar radius
• Every star undergoes what specific stages depending on its internal structure and how it produces energy?

  evolutionary stages
• What are the three evolutionary stages?

  1. Main sequence
  2. Giant and Supergiant
  3. White dwarf
• All stars start as a what?

  Nebula
• What is a nebula?

  a cloud of dust and gas
• What is a protostar?

  a young star building its dense core
• Is the sun a main sequence star?

  Yes