The constellation of Orion represents the Hunter for most of the year, but in mid-March the bright stars of this prominent cluster of stars are hunted by skygazers.
Named after the pinnacle of human excellence in hunting in Homer’s epic Greek poem The Odyssey, the stars of Orion shine brightly in the southwestern sky throughout March. The Orion Nebula, the closest star-forming region to Earth, is easy to find within the constellation and can even be spotted with binoculars in reasonably dark skies.
To find Orion, look up at the southern or southwestern sky just after sunset, when the stars are appearing. In the following months the constellation will move west.
Related: Orion Constellation: Facts, Location and Stars of the Hunter
The Orion constellation is made up of several distinctive features, including the Sword of Orion, which descends from Orion’s three-star belt. Both Orion’s Sword and Orion’s Belt are asterisms, loosely unofficial patterns of stars that, like constellations, seem to take the form of familiar or mythical objects.
The stars that matter Orion’s beltalso known as the Three Kings or the Three Sisters, the central star is Alnilam, a bright supergiant, and Alnitak and Mintaka – both actual star systems composed of three and five stars, respectively.
Within Orion’s sword are the stars 42 Orionis and Theta Orionis, the multiple star system Iota Orionis, and the bright nebula Messier 42, also known as the Orion Nebula or NGC 1976.
With binoculars, this nebula appears as a fuzzy greyish spot. But the observing power of even a medium-sized telescope is enough to resolve the veils of gas and darker dust lanes that make up Messier 42. This material forms the building blocks for the new stars being born in this region.
At the heart of Messier 42 and about 1,600 light-years from Earth is the Trapezoidal Cluster, or Theta-1 Orionis, a large open cluster of young stars that can be resolved with 5-inch telescopes and larger. The young stars in the trapezoid emit X-rays, lighting up the surrounding nebula.
Accordingly MessierObjects.com (opens in new tab), The Trapezoidal Cluster is named for the loose cluster of four massive stars that form a trapezoidal asterism at its heart. These stars are designated Theta-1 Orionis A, B, C, and D, with Theta-1 Orionis C being the brightest of them, with a visual magnitude of 5.13. The star is a whopping 251,000 times more luminous than the Sun, making it one of the brightest stars ever discovered.
The Theta-1 Orionis A and B stars form a binary pairing, with the stars eclipsing each other as seen from Earth. Theta-1 Orionis B is also the faintest star in the trapezoidal asterism.
The trapezoidal cluster is also believed to host a multitude of so-called “failed stars” or brown dwarfs. These are bodies with masses larger than giant planets like Jupiter but smaller than stars. This lack of mass means brown dwarfs are unable to initiate the nuclear fusion that defines stars. As a result, they are dark objects, meaning they are undetectable even with a large backyard telescope.
Another thing skygazers can’t see in the Trapezium cluster, even if Orion is visible this March, is the intermediate-mass black hole with a mass 100 times that of the Sun that scientists suspected in 2012 that it exists in the heap.
If you’re hoping to catch a glimpse of the Orion constellation and its stellar denizens, our guides are for you best telescopes And best binoculars are a good start.
If you want to take photos of Orion or the night sky in general, check out our guide how to photograph the moonas well as ours The best cameras for astrophotography And The best lenses for astrophotography.
Editor’s note: If you photograph Orion, its stars, or the Orion Nebula and would like to share it with Space.com readers, send your photos, comments, and your name and location to [email protected].
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