Difference between revisions of "Vega"
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==Known Places Around Vega== | ==Known Places Around Vega== | ||
| − | None yet, but it does have a disk of dust so planets may be possible. | + | None yet, but it does have a disk of dust so planets may be possible - or the dust cloud might not have coalesced into planets yet. |
{{interstellar}} | {{interstellar}} | ||
Revision as of 01:39, 2 December 2010
| Vega | |
| Stellar characteristics | |
|---|---|
| Constellation | Lyra |
| Right ascension (Epoch J2000) | 18h 36m 56.3364s |
| Declination (Epoch J2000) | +38° 47' 01.291" |
| Spectral type | A0V |
| Distance from Sol | 25.3 ± 0.1 ly |
| Other designations | Wega, Lucida Lyrae, Alpha Lyrae, α Lyrae, Alp Lyr, Alf Lyr, 3 Lyr, HR 7001, Gl 721, Hip 91262, HD 172167, BD +38°3238, SAO 67174, FK5 699, GCTP 4293.00, LTT 15486, LTT 15486, ADS 11510 A |
Vega, also known as Alpha Lyrae, is a slightly bluish, white main sequence dwarf star of spectral and luminosity type A0 V, like Sirius, and is located aproximately 25.3ly from Sol. According to various estimates, the star has 2.3 to 3.1 times Sol's mass, 2.73 +/- 0.01 times its diameter (Aufdenberg et al, 2006; and Ciardi et al, 2001), and 37 +/- 3 times (true A0V average derived by Aufdenberg et al, 2006) to 58 times (pole on) its luminosity. Like Sirius, however, Vega radiates much more in ultraviolet wavelengths than Sol, and, not surprisingly, the European Space Agency has used ultraviolet spectral flux distribution data to determine stellar effective temperatures and surface gravities, including those of Vega. The star may be about only 63 percent as enriched as Sol with elements heavier than hydrogen ("metallicity") based on its abundance of iron (D. Gigas, 1986, but more recent findings on Vega's mild underabundance of metals can be found in Ilijic et al, 1998). On the other hand, its iron metallicity has been measured anywhere from four to 115 percent of Sol's (Cayrel de Strobel et al, 1991, page 31).
Vega may be only about 350 million years old (Maeder and Meynet, 1988). However, it is so much bigger and hotter than Sol that it will exhaust its core hydrogen after only another 650 million years or so (for a total life of around a billion years) and turn into a red giant or Cepheid variable before puffing away its outer layers to reveal a remnant core as a white dwarf. The star is a rapidly rotating star whose apparent "pole-on" view from Earth distorts its various stellar characteristics (Aufdenberg et al, 2006; and Gulliver et al, 1994).
Due to the slowly changing orientation of Earth's axis in space (which is also known as the Precession of the Equinoxes), Vega was the North Celestial Pole Star some 12,000 years ago and will be again in another 10,000 years.
(Boilerplate taken from SolStation.com)
Known Places Around Vega
None yet, but it does have a disk of dust so planets may be possible - or the dust cloud might not have coalesced into planets yet.
