On nights when the gloomy January clouds part to reveal a clear sky, the familiar presence of Orion is always a reassuring sight. Instantly recognisable by his iconic belt of three stars, this winter constellation is one of my favourites. Named for the hunter in Greek mythology, said to be placed among the stars by the gods, the full constellation shows him raising his club and shield high. Or maybe it is actually an animal skin? Or a bow? Numerous cultures have a story for this constellation, and in Australia, where from our point of view the constellation appears upside-down, the three stars of Orion’s belt are even seen as a saucepan!
Below Orion’s belt, there appears to be a cluster of smaller stars, said to represent his sword. In fact, the middle star of the sword is not a star at all, but the Orion Nebula; a massive cloud of space gas and dust where stars are born. Though it may appear fuzzy even to the naked eye, a simple pair of binoculars or small telescope is enough to observe the cloudy shape of the nebula.
Betelgeuse, a massive red supergiant, looks noticeably redder that its opposite corner companion, the blue supergiant Rigel.
The main body of Orion is made up of seven stars, including the three making up the belt, that form an hourglass shape interpreted as Orion’s shoulders and legs. The two brightest stars are Betelgeuse at the top left, and Rigel in the bottom right. It is fascinating to compare the colour of these stars — Betelgeuse, a massive red supergiant, looks noticeably redder that its opposite corner companion, the blue supergiant Rigel. In astrological time, both are nearing the end of their life.
Betelgeuse in particular generated huge interest in 2019, appearing noticeably dimmer for a few months and causing speculation as to whether the star was about to go supernova, before returning to regular brightness by February the next year. This has been attributed to a cool spot on the star’s surface, causing it to spit out an obscuring cloud of gas. Even so, it is expected that the star will explode as a supernova within the next 100,000 years, an event which will make the dying star appear brighter than our own moon and clearly visible during the day. What an incredible sight that will be!
Betelgeuse is also part of another well-known pattern of stars, known as the Winter Triangle
While it’s still around, Betelgeuse is also part of another well-known pattern of stars, known as the Winter Triangle. A pattern of stars like this, that is not officially recognised as a constellation, is known as an asterism. The Winter Triangle is, as the name suggests, visible from December to April in the Northern Hemisphere, and is formed of three of the brightest stars in the sky: Sirius, Procyon, and Betelgeuse. As these stars are so easy to spot, it can be a useful point of reference when stargazing.
Sirius, also known as the “dog star”, is part of the constellation Canis Major (the Great Dog), while Procyon sits in the constellation of Canis Minor (the Little Dog). Look out for these two loyal hounds following Orion faithfully across the winter skies.
All pictures sourced from Bing’s image search, filtered to a licence of “free to share and use”.
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