Betelgeuse(redirected from Alpha Orionis)
Also found in: Dictionary, Thesaurus, Wikipedia.
Related to Alpha Orionis: Beta Orionis, Delta Orionis
Betelgeuse(bēt`əljo͞oz'), bright star in the constellation OrionOrion,
in astronomy, constellation located on the celestial equator. It is one of the most conspicuous and easily recognizable constellations in the entire sky. From ancient times it has been mentioned in the literature of many peoples and is traditionally depicted as the figure
..... Click the link for more information. ; Bayer designation α Orionis; 1992 position R.A. 5h54.8m, Dec. +7°24'. A red supergiant with a luminosity about 13,000 times that of the sun, it is of spectral classspectral class,
in astronomy, a classification of the stars by their spectrum and luminosity. In 1885, E. C. Pickering began the first extensive attempt to classify the stars spectroscopically.
..... Click the link for more information. M2 Iab. Betelgeuse is a semiregular variable starvariable star,
star that varies, either periodically or irregularly, in the intensity of the light it emits. Other physical changes are usually correlated with the fluctuations in brightness, such as pulsations in size, ejection of matter, and changes in spectral type, color, or
..... Click the link for more information. with apparent magnitudemagnitude,
in astronomy, measure of the brightness of a star or other celestial object. The stars cataloged by Ptolemy (2d cent. A.D.), all visible with the unaided eye, were ranked on a brightness scale such that the brightest stars were of 1st magnitude and the dimmest stars
..... Click the link for more information. ranging from 0.06 to 0.75; thus, at maximum brightness it is one of the 10 brightest stars in the sky. Betelgeuse marks the right shoulder of Orion; its distance is about 500 light-years.
Betelgeuse(bee -t'l-jooz) (α Ori) A remote luminous red supergiant that is the second-brightest star in the constellation Orion. It is a semiregular variable with a period of about 5.8 years; the normal magnitude range is 0.3 to 0.9 but the magnitude has reached 0.15 and been as low as 1.3. It is a strong source of infrared radiation. IRAS found that the long-wavelength infrared is emitted from three concentric shells, the largest with a radius of 1.5 parsecs, ejected within the past 100 000 years. Images of the surface of Betelgeuse have been produced by various interferometry techniques, and indicate a nonuniform brightness. Mv : –5.7; spectral type: M2 Iab; diameter: about 500 times solar diameter; distance: 150 pc.
An orange-red giant star of stellar magnitude 0.1-1.2, 650 light-years from the sun, spectral classification M2-Iab, in the constellation Orion; the star α Orionis.