Vega(redirected from Gliese 721)
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Vega(vā`gə), brightest star in the constellation LyraLyra
[Lat.,=the lyre], northern constellation lying S of Draco, E of Hercules, and W of Cygnus. Although many civilizations represented it as a bird, it was also depicted as a tortoise.
..... Click the link for more information. ; Bayer designation Alpha Lyrae; 1992 position R.A. 18h36.7m, Dec. +38°47'. A white main-sequence star 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. A0 V, its 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. is 0.1, making it the fifth brightest star in the sky. Vega is about three times the size of the sun and 50 times as luminous. Its distance from the earth is 26 light-years. Its name is from the Arabic for "falling eagle," referring to the figure that the Arabs associated with the constellation Lyra.
Vega(vee -gă) (α Lyr) A conspicuous white star, apparently blue in color, that is the brightest star in the constellation Lyra. It was the pole star about 12 000 years ago, at the end of the last Ice Age. Because of precession, it will be the pole star again around ad 14 000. Vega is the standard A0 V star (B–V = U–B = 0) in the UBV system. Observations of Vega by the satellite IRAS in 1983 revealed an infrared excess beyond 10 μm. The excess is attributed to thermal radiation from particles more than 1mm in radius located about 85 AU from Vega and heated by the star to a temperature of 85 K. It appears that the large particles have arisen from the residual prenatal cloud of gas and dust and may perhaps represent an embryonic and developing planetary system. Because Vega is a bright A0 star with a short lifetime (3 × 108 years) a ‘solar system’ will not have sufficient time to form around it. (The age of our Solar System is 4.6 × 109 y.) mv : 0.03; Mv : 0.6; spectral type: A0 Va; distance: 7.5 pc.
a wooden trapping ship, built in 1873, with a displacement of 360 tons. In 1877, financed by the Russian industrialist A. M. Sibiriakov, the Swedish entrepreneur O. Dickson, and King Oskar II, the Vega was equipped for a scientific arctic expedition under the leadership of N. A. E. Nordenskiöld. In 1878-79, the Vega first traversed the Northeast Passage along the northern coast of Europe from west to east with only one winter stay (eastward from the Koliuchin Inlet to 200 km from the Bering Sea). The crew consisted of 21 men, the captain being Lieutenant A. Palander.