The hunter in our skies: Orion

The constellation of Orion

Orion takes the shape of a hunter. In Greek mythology, Orion was a  hunter. He was killed by the sting of a scorpion. This is why even in the night sky, the constellations of Scorpius and Orion are never found in the same part of the sky. Just north of Orion is the Pleiades, a famous open cluster of stars visible to the naked eye. The seven brightest stars of the Pleiades are also connected to Orion through a folklore. It is believed that they represent the Seven Daughters of Atlas, whom Orion chased. This is reflected in their positions in the night sky. 

Orion’s brightest star is Rigel, though it is occasionally usurped by Betelgeuse (Betelgeuse is a variable star). Betelgeuse marks one of the shoulders of Orion, whereas Rigel marks the foot. Rigel is hot, bluish star. Betelgeuse, on the other hand, is a red supergiant, a star reaching the end of its life. Orion’s belt, which is made up of three stars, is the closest segregation of such bright stars in the night sky. 

Orion is also home to the Orion nebula, a nearby region of star birth. Images from the Hubble Space Telescope indicate proto-planetary disks inside the nebula, which indicate the birth of new planetary systems. Orion nebula can be seen with the naked eye on really dark nights, just below Orion’s belt. 

The Orion nebula as seen through the Hubble space telescope

Enjoy Orion while it lasts. Like I said, this constellation contains many blue stars, which means that these stars have very short lifetimes. Within 20 million years, not even one recognizable bright star in the constellation will remain (most probably!). This is because blue stars, unlike our Sun and other less massive stars, use vast amounts of energy to fuel their nuclear fusion. So, they use up their fuel much faster than other stars, leading to their early deaths. 

Right now in the Northern Hemisphere, Orion is visible in the wee hours of the morning. As the winter progresses up here, Orion will slowly replace the summer triangle (Vega, Altair and Deneb) in the skies of the late evening. The constellation has been a source of wonder ever since ancient times and will continue to enthrall the posterity, long after our generation ceases to exist.