What is Vega?
Vega is a star with slightly more than twice the mass of the Sun, located 25.3 light-years away in the constellation of Lyra, the lyre. Along with Arcturus and Sirius, it is one of the brightest stars in our local neighborhood, being the fifth brightest star in our sky. After Arcturus, Vega is the next brightest star in the northern celestial hemisphere. Together with the Sun, Vega is located within the Local Bubble, a region of space 300 light-years across with only about 10% the average density of the interstellar medium.
Vega's name comes from the Arabic word waqi meaning "falling". This is a reference to the time when people regarded the constellation Lyra as a swooping vulture rather than a lyre. Vega is the brightest star in the constellation Lyra, and a vertex of the Summer Triangle, an asterism where connects the constellations of Aquila, Cygnus, and Lyra. In about 12,000 years, Vega will become the new North Star due to the precession of the equinoxes, a slight change in star patterns due to changing inclination of the Earth's rotational axis.
Although Vega's mass is only twice that of the Sun, it has 30 times the luminosity. Because more massive stars burn their hydrogen fuel more rapidly, Vega's estimated lifetime is about one billion years, a tenth that of the Sun. After it uses up most of the hydrogen in its core, it will start fusing helium and expand to become a Red Giant. An oxygen-carbon white dwarf remnant will remain, and the envelope of the star will be ejected to form a planetary nebula.
For many years, Vega was used to represent 0 on the astronomical brightness scale, with brighter stars than Vega having negative values and fainter stars than Vega having positive values. Only the Sun, Sirius, Canopus, Arcturus, and Alpha Centauri are brighter stars.
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