The Constellation Orion

1
TheConstellation Orion
RyukyuAstronomy Club28 March 2009
2
Discussion Topics

• Locating Orion
• Mythology of Orion
• Brightest Stars in Orion
• Orion Nebula
• Trapezoid Star Cluster
• Horsehead Nebula
• Double stars in Orion

3
Locating Orion
Orion is the key to locating the
constellations of the Winter Sky
4
Locating Orion
5
Mythology of Orion

• In Greek mythology, Orion was a great hunter who
  eventually offended the gods, especially Apollo.
  Apollo tricked Artemis, the Goddess of the hunt,
  into shooting Orion on a bet. When she discovered
  that she had shot Orion, she quickly lifted him
  to the heavens and made him immortal, where he
  now hunts eternally with his two dogs, Canis
  Major and Canis Minor. In front of him is his
  prey Taurus the Bull.

6
Brightest Stars of OrionAnd Deep Sky Objects
Meisaa
Betelgeuse
Bellatrix
Mintaka
Alnilam
Alnitak
Horsehead Nebula
Trapezium
M42 Orion Nebula
Rigel
Saiph
7
Brightest Stars of Orion

• Betelgeuse "Alpha Orionis" is a massive red
  supergiant star nearing the end of its life. It
  is the second brightest star in the Orion
  constellation and the twelfth brightest star in
  the night sky.
• Rigel "Beta Orionis" is a blue supergiant that
  is the seventh brightest star in the night sky.
• Bellatrix "Gamma Orionis is the twenty-second
  brightest star in the night sky. Bellatrix is
  considered a blue giant, though it is too small
  to explode in a supernova. Its luminosity is
  derived from its high temperature rather than its
  radius. Bellatrix serves as Orion's "left
  shoulder.
• Mintaka "Delta Orionis is the faintest of the
  three stars in Orions belt. It is a multiple
  star system composed of a large blue giant and a
  more massive white star. Mintaka is the
  westernmost of the three stars that constitute
  Orion's Belt.
• Alnilam "Epsilon Orionis," is a blue supergiant,
  despite being nearly twice as far from the Sun as
  Mintake and Alnitak, the other two belt stars.
• Alnitak "Zeta Orionis" is the easternmost star
  in Orion's Belt. It is a triple star 800 light
  years distant, with the primary star being a hot
  blue supergiant.
• Saiph "Kappa Orionis serves as Orion's right
  foot. It is of a similar distance and size to
  Rigel, but appears much fainter, as its hot
  surface temperature (46,000F or 26,000C) causes
  it to emit most of its light in the ultraviolet
  region of the spectrum.

8
M42 TheOrion Nebula

• - Interstellar cloud of hydrogen,
• dust, and plasma.
• 1300 light years away
• 24 light years across
• Visible to naked eye

9
Trapezium Star Cluster

• Over 1000 young stars
• Estimated 1M years old
• Most stars clouded from
• view by dust
• Only 4-5 stars visible
• with small scope

10
The Horsehead Nebula
11
Double Stars in Orion
Star Magnitudes Separation Notes
Rigel (beta) 0.1, 6.8 9.5 Difficult because of glare from primary.
Alnitak (zeta) 1.9, 4.0 2.3 Test for 75mm telescope
Mintaka (delta) 2.2, 6.3 53 Wide separation
Eta 3.8, 4.8 1.5 Test for 100mm telescope
Sigma 3.7, 10, 7.5, 6, 8 11, 13, 42, 30 Quintuple star all components visible to small telescope
Theta_1 6.8, 7.0, 5.4, 6.3 - The Trapezium (see earlier slide)
Iota 2.7, 6.9, 11 11, 50
?747 4.7, 5.5 36 Wide separation same field as Iota
Lambda 3.6, 5.5 4.4
Rho 4.5, 8.3 7
12
OrionStars to mag 7.0 Double stars indicated
by
13
Finally, The Okinawan Mythology for Orion