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Line 33:
Line 33: − Vega is considered a very young star, and is estimated to be only some 350 million years old<ref>http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1988A%26AS...76..411M</ref>. Because it is far larger and hotter then our Sun, Vega will exhaust its core hydrogen only after another 650 million years or so, and leaving the main sequence turning into a red giant or a Cepheid variable. − [[Image:Size Vega.png|thumb|left|250px|illustration of the size of Vega compared to the sun, note its elliptical shape due to its rotation speed.]]
→The Star
Vega is a main sequence star of spectral class A0 V, much like [[Sirius]]. Vega is 2.3 to 3.2 times as massive as our Sun, and some 2.73 times its diameter<ref>http://lanl.arxiv.org/abs/astro-ph/0603327</ref>. Vega is considerably more luminous, being 37 times the Sun's luminosity at the equator and 58 times as much at the poles. Like all class A stars, most of the radiation from Vega is in the [[ultraviolet]]. Vega is only some 63 percent as enriched as the [[Sun]], based on its abundance of [[iron]]<ref>http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1986A%26A...165..170G</ref>.
Vega is a main sequence star of spectral class A0 V, much like [[Sirius]]. Vega is 2.3 to 3.2 times as massive as our Sun, and some 2.73 times its diameter<ref>http://lanl.arxiv.org/abs/astro-ph/0603327</ref>. Vega is considerably more luminous, being 37 times the Sun's luminosity at the equator and 58 times as much at the poles. Like all class A stars, most of the radiation from Vega is in the [[ultraviolet]]. Vega is only some 63 percent as enriched as the [[Sun]], based on its abundance of [[iron]]<ref>http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1986A%26A...165..170G</ref>.
Vega rotates so fast that it only takes some 12.5 hours to complete one rotation, in comparison the Sun which takes 25.4 days to complete one rotation. This rotation is so fast that observations suggest that the star is rotating at some 91 percent of the angular velocity needed to cause the star to physically fly apart. Vega is thus 23 percent wider along its equator than at its poles, as well as some 2300K cooler<ref>http://www.noao.edu/outreach/press/pr06/pr0603.html</ref>. Here on Earth, Vega is seen as pole on (looking directly at its pole).
Vega rotates so fast that it only takes some 12.5 hours to complete one rotation, in comparison the Sun which takes 25.4 days to complete one rotation. This rotation is so fast that observations suggest that the star is rotating at some 91 percent of the angular velocity needed to cause the star to physically fly apart. Vega is thus 23 percent wider along its equator than at its poles, as well as some 2300K cooler<ref>http://www.noao.edu/outreach/press/pr06/pr0603.html</ref>. Here on Earth, Vega is seen as pole on (looking directly at its pole).