The Orion Nebula (M42) is middle "star" in his sword:
Orion the Hunter dominates January's evening sky as the most recognizable constellation visible from both Northern and Southern hemispheres, anchored by two of the brightest stars in Earth's night sky: Betelgeuse (Alpha Orionis, magnitude +0.50, red supergiant his-right shoulder) and Rigel (Beta Orionis, magnitude +0.13, blue-white supergiant his-left foot).
Betelgeuse, approximately 548 light-years distant, is a dying red supergiant in its final evolutionary stages. If placed at our Sun's position, its surface would extend beyond Mars' orbit (diameter ~700 times larger than the Sun). Astronomers predict Betelgeuse will explode as a supernova within the next 100'000 years, potentially outshining the Full Moon for weeks during the daytime when it occurs.
Rigel, 860 light-years away, is a blue supergiant 120'000 times more luminous than our Sun. If Rigel replaced our Sun, Earth would vaporize instantly. Orion's Belt three nearly-equally-spaced stars (Alnitak, Alnilam, Mintaka) serves as the most famous asterism in astronomy, used for navigation and seasonal timekeeping for millennia. Below the Belt, hangs Orion's Sword. The second (middle) star in his sword is actually the Orion Nebula (M42), visible to naked eyes as a fuzzy patch and spectacular through binoculars. This is not a single star but a massive gas nursery 1'344 light-years distant where thousands of stars are forming from collapsing gas clouds.
Greek mythology: Orion the Hunter, killed by a scorpion (the Scorpius constellation), placed in the sky opposite each other so they never appear together. When Orion sets in the west, Scorpius rises in the east.
#orion, #constellation, #betelgeuse, #rigel, #nebula, #m42
