One of the most easily recognizable constellations in our night sky is Orion The Hunter, especially here in North America during the winter months.
The constellation, made up of a quadrangle of four bright stars in our evening sky shaped like an hour glass with three additional evenly spaced stars making up the center (or belt), gives Orion its distinctive look. Although they look like tiny dots of light in our evening sky here on Earth, all of them are actually much larger than our own yellow Sun.
While the G-type main-sequence star that inhabits the center of our own Solar System seems huge -- and make no mistake it is compared to the rest of the planets that orbits it -- next to the Constellation Orion stars, its relatively small in terms of scale and mass.
Here are a few fun scientific facts about each of these bright stars.
Rigel (or Beta Orionis) is generally the seventh-brightest star in the night sky and the brightest star in Orion. Rigel is a spectral type B8Ia blue supergiant (BSG) star approximately 120,000 times as luminous as our own Sun and is 18 to 24 times as massive in scale.
It is the brightest and largest component of a star system of at least four stars that appear as a single blue-white point of light to the naked eye as seen here on Earth. The three smaller stars of this system are all blue-white main-sequence stars, each three to four times as massive as the Sun.
The Rigel system is located at a distance of approximately 860 light-years (or 260 parsecs) from the Sun.
Betelgeuse (or Alpha Orionis) is a red supergiant star that is the second-brightest star in the constellation, and the tenth-brightest star in the night sky. It is also the largest star in Orion with an estimated radius between 640 and 764 times that of the Sun -- which would roughly be the distance between the center of our Sun to the somewhere between the orbits of Mars and Jupiter!
Betelgeuse lies about 642 light-years (or 197 parsecs) from our Solar System. Because Betelgeuse is a red supergiant, while it is much
larger and closer to us than Rigel, it burns less brightly due to the late stage of its
celestial lifespan.
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| Size comparison of Betelgeuse and Rigel compared to our Sun and other stars. |
Bellatrix (or Gamma Orionis) is the third-brightest star in Orion, and typically the 25th-brightest star in our night sky. Bellatrix is a B2 III-type giant star about six time the size of our own yellow Sun, and located about 244 light-years (or 75 parsecs) from the Sun, making Bellatrix the closest of the Orion constellation stars to our Solar System.
Saiph (or Kappa Orionis) is the other blue supergiant star that makes up the forth star in the constellation's main quadrangle. It is the sixth-brightest star in Orion with an estimated distance of about 650 light-years (or 200 parsecs) from the Sun.
Orion's
Belt is one of the most recognizable asterisms in the night sky and easily one of the most easily identifiable parts
of the constellation Orion consisting of three bright stars nearly equally spaced in a line in our night sky as
seen from our vantage point here on Earth. Although they appear close to
each other in the night sky, they are at varying distances some of the farthest Orion stars from our Solar System and each other.
Alnitak (or Zeta Orionis), the easternmost star in Orion's Belt, is a triple star system
approximately 1,260 light-years (or 486 parsecs) from our Solar System. The primary star, Alnitak
Aa, is a hot blue supergiant and the brightest Class O star in our night
sky. It has two companion stars: Ab and B. It's the fifth brightest star in Orion and the 31st brightest star in the night sky.
Alnilam (or Epsilon Orionis), the
central star in Orion's Belt, is a massive blue supergiant around 1,344 light-years (or 412 parsecs) making it the farthest Orion star from our Solar System. Its
the brightest of the three stars in Orion's Belt and the fourth-brightest star in the Orion
constellation. Alnilam is also the 29th-brightest star in our night sky and about 40 times the mass of our own Sun.
Mintaka (or Delta Orionis), the westernmost star, is located about 1,240
light-years (or 380 parsecs) from our Solar System and is closest to the celestial equator. It is a
multiple-star system composed of three spectroscopic components of about six stars, the main one being a Class O blue supergiant star similar to Alnitak Aa.
The
stars of Orion's Belt are several times more massive than the sun and
thousands of times brighter. Combined, the ten
stars of these three systems possess a luminosity approximately 970,000
times that of our own Sun!
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| The size of the Orion Belt stars compared to our own Sun. |
One more fun fact for all you amateur stargazers out there is that you can actually use these stars of Orion as a guide to locating other stars and nearby constellations. Please be sure to check out my previous blog post on the subject HERE.
