Quiz

• What form do you see? Big Bear and Small Bear, Big Dipper and Small Dipper, Hunter (Orion), Winter Constellation, Dog (Canis Major)
• Can be seen in February
• Star


  • The objects that heat and light the planets in a system
  • A ball of plasma held together by its own gravity
  • Nuclear reactions occur in stars (H → He)
  • Energy from the nuclear reactions is released as electromagnetic radiation
• Nuclear fusion


  • When two atoms bond together to make one heavier atom
  • The process releases large amounts of energy
• The two most abundant elements in stars are 71% HYDROGEN and 27% HELIUM
• How a Light Shows Composition

  1. Scientists look at the light from a star through a SPECTROSCOPE

  2. A spectroscope breaks light apart and shows the wavelengths of the light

  3. The bright lines on the spectrum tell you the wavelength of the light given off
• Red Giant


  • Large red star at least 10x diameter of the sun
  • Old Stars
  • The sun will swell into a Red Giant when it is old
• Super Giant


  • Largest of all stars 100x more luminous
  • Explode as a Super Nova
  • Can form Black Holes
• Dwarf Stars


  • Less luminous
  • Very dense, mostly carbon
  • Tightly packed nuclei
  • Remains of a red giant that ran out of fuel
  • 1 cup full of star =20 tons or 5 elephants
  • Most are red/orange/yellow
  • White dwarf is the exception to the color
  • Sun is a yellow dwarf
• Distance


  • Measured in light-years
  • The distance which a ray of light would travel in one year
  • About 6,000,000,000,000 (6 trillion) miles
  • 186,000 miles per second
• Magnitude (brightness)


  • A measure of brightness of celestial objects
  • Smaller values represent brighter objects than larger values
  • Apparent magnitude - How bright a star appears to be from Earth
  • Absolute magnitude (luminosity) - How bright a star actually is
• Temperature & Color


  • The color of a star indicates the Temperature of the star
  • Stars are classified by T (decreasing T: O, B, A, F, G, K, M)
• Hertzsprung-Russell Diagram relates the brightness of stars to its surface temperature
• Life Cycle of Stars

  1. Begin as clouds of dust and gas called nebulae

  2. Gravity may cause the nebula to contract

  3. Matter in the gas cloud will begin to condense into a dense region called a protostar

  4. The protostar continues to condense, it heats up. Eventually, it reaches a critical mass and nuclear fusion begins

  5. Begins the main sequence phase of the star

  6. Very large, massive stars burn their fuel much faster than smaller stars

  7. Eventually, the star's fuel will begin to run out

  8. It will expand into what is known as a red giant

  9. Massive stars will become red supergiants

  10. Most average stars will blow away their outer atmospheres to form a planetary nebula

  11. If the star is massive enough, the collapse will trigger a violent explosion known as a supernova

  12. If the remaining mass of the star is about 1.4 times that of our Sun, the core is unable to support itself and it will collapse further to become a neutron star

  13. If the remaining mass of the star is more than about three times that of the Sun, it will collapse so completely that it will literally disappear from the universe. What is left behind is an intense region of gravity called a black hole
• Constellations


  • A group of stars that form a pattern in the sky
  • Star patterns are shaped like persons, animals, and inanimate objects
  • Most of the constellation names we know came from the ancient Middle Eastern, Greek, and Roman cultures
• The International Astronomical Union currently recognizes 88 constellations
• The constellations you see depend on your location, date, and time
• Most constellations have legends, myths, or stories behind them
• Planisphere or Star Wheel, Celestial Star Globe


  Used to find constellations
• Light pollution from city lights hides many of the dim stars, making it harder to recognize the full constellation patterns
• You see different constellations from each hemisphere
• Zodiac Constellations


  • The group (or "belt") of constellations that fall along the plane of the ecliptic
  • While there are 12 astrological constellations of the zodiac, there are 13 astronomical zodiac constellations
• Zodiac Constellations


  • Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Ophiuchus
• The Seven Major Constellations

  • Cassiopeia, Cygnus, Scorpius, Draco, Orion, Ursa major, Ursa minor
• Cassiopeia


  The queen of Ethiopia who was so proud of her beauty that she offended the sea god Poseidon, who placed her figure among the stars
• Cygnus


  The constellation representing a swan, formed by the spirit of a snow goose that was shot and fell into a lake
• Orion


  The constellation representing a hunter, who was boastful and was killed by a scorpion sent by the goddess Gaia
• CASSIOPEIA – "THE QUEEN"
• Cassiopeia


  • Brightest Star – Schedar
  • Best season to view – all year
  • It was one of 48 constellations listed by the 2nd-century Greek astronomer Ptolemy
• The Myth: 'One day three hunters were hiking through the forest when they came upon a clear lake. The lake was home to many birds including a beautiful snow goose. One hunter shot his bow and the snow goose fell into the lake. As the sky darkened, the spirit of the snow goose formed a constellation in the sky.'
• CYGNUS – "THE SWAN"
• Cygnus


  • Brightest Star – Deneb
  • Best season to view – all year
  • Visible in Manila in September but not in March
• ORION – "THE HUNTER"
• Orion


  • Brightest Star – Rigel and Betelgeuse
  • Best season to view – the winter
• The Myth: 'Orion was a very good hunter, but also boastful. Gaia, the goddess of Earth, became fed up with Orion's boast so she sent a deadly scorpion to kill the hunter. The scorpion ended Orion's bragging. Both Orion and Scorpius were placed in the sky but to avoid any further battles, they are never in the sky at the same time. Orion is seen in the winter and Scorpius is seen in the summer.'
• SCORPIUS – "THE SCORPION"
• Scorpius


  • Brightest Star – Antares
  • Best season to view – summer
• The Myth: 'To the ancient Greeks, the constellation Scorpius was the image of a scorpion. The constellation was related to the death of the giant hunter Orion. There are several different stories about Orion's death. According to one story, Orion wanted to kill all the earth's wild animals, but the Earth goddess Gaia got angry because she made the animals. The goddess sent a scorpion to attack Orion. The scorpion stung Orion to death with its tail. As a reward, Gaia changed the insect into a constellation.'
• URSA MAJOR – "BIG BEAR"
• Ursa Major


  • Brightest Star – Dubhe and Merak
  • Best season to view – all year (Circumpolar)
  • Can be seen in North; main asterism viewed in south