Stars and Constellations

• Stars - It is a massive ball of plasma held together by its own gravity

  and emits light throughout the universe.
• Sun is the closest star to Earth. It is by far the largest object and the only star in our solar system.
• The sun is about 70% hydrogen and 28% helium by mass while the remaining 2% is composed of traces of “metals”.
• Sun has lived for 4.6 billion years
• Proxima Centauri - Second closest star to earth.
• Nuclear fusion is the reaction that converts hydrogen atoms into helium atoms releasing a tremendous amount of heat, causing the gas to glow.
• Determine the life cycle of the star:

  A) Stellar Nebula

  B) Average Star

  C) Massive Star

  D) Red Giant

  E) Red Supergiant

  F) Planetary Nebula

  G) Supernova

  H) White Dwarf

  I) Neutron Star

  J) Black Hole

  
• Sun is a star that can be seen during daytime.
• The brightness of a star is described in terms of magnitude and luminosity.
• The ancient Greeks learned that the brightness of a star depends on its size and distance to earth
• A star's color depends on its surface temperature.
• Colors of stars (Hottest to coldest.):

  Blue -> Blue-White -> Yellow -> Orange -> Red
• About 90% of all stars are main sequence stars.
• Characteristics of a star:

  • Brightness
  • Color
  • Size
  • Mass
• Latin word “con” means group and “stella” means stars.
• Constellation - It refers to a group of stars that appears to form a pattern or particular shape in the sky.
• Asterism – the star patterns that have been discovered but have not been officially identified as constellation.
• Astronomers officially recognize 88 constellations distributed in the entire space.
• Polaris - is the North star because it is located close to the north celestial pole.
• Polaris - It usually serves as a guide by seafarers.
• Orion - named after a hunter in Greek mythology.
• Ursa major - Located above the horizon in the northern latitudes.
• Ursa Major - Best known as the home of the big dipper.
• Ursa Major - Most universally recognize constellation.
• Cassiopeia- Constellation of the northern sky easily recognized by

  a group of five bright stars forming a slightly irregular shape.
• Canis Major is a constellation in the southern sky. Its name means “the greater dog” in Latin.
• Draco - in Greek mythology, this was the dragon slain by the warrior Hercules, who is represented by a neighboring constellation.
• Star name: Orion.

  
• Star name: Ursa Major.

  
• Star name: Cassiopeia.

  
• Star name: Canis Major.

  
• Star name: Draco.

  
• Star name: Hercules.

  
• Hercules - Visible in both the Northern and Southern hemispheres.