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Bételgeuse
Betelgeuse is a red supergiant star in the constellation of Orion. It is usually the tenth-brightest star in the night sky and, after Rigel, the second brightest in its constellation. It is a distinctly reddish, semiregular variable star whose apparent magnitude, varying between +0.0 and +1.6, with a main period near 400 days, has the widest range displayed by any first-magnitude star. Betelgeuse is the brightest star in the night sky at near-infrared wavelengths. Its Bayer designation is , Latinised to Alpha Orionis and abbreviated Alpha Ori or . With a radius between 640 and 764 times that of the Sun, if it were at the center of the Solar System, its surface would lie beyond the asteroid belt and it would engulf the orbits of Mercury, Venus, Earth, and Mars. Calculations of Betelgeuse's mass range from slightly under ten to a little over twenty times that of the Sun. For various reasons, its distance has been quite difficult to measure; current best estim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orion (constellation)
Orion is a prominent set of stars visible during winter in the northern celestial hemisphere. It is one of the IAU designated constellations, 88 modern constellations; it was among :Constellations listed by Ptolemy, the 48 constellations listed by the 2nd-century astronomer Ptolemy. It is named after Orion (mythology), a hunter in Greek mythology. Orion is most prominent during winter evenings in the Northern Hemisphere, as are five other constellations that have stars in the Winter Hexagon asterism (astronomy), asterism. Orion's two brightest stars, Rigel (β) and Betelgeuse (α), are both among the List of brightest stars, brightest stars in the night sky; both are supergiants and slightly variable star, variable. There are a further six stars brighter than magnitude 3.0, including three making the short straight line of the Orion's Belt asterism (astronomy), asterism. Orion also hosts the radiant (meteor shower), radiant of the annual Orionids, the strongest meteor shower as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
