Lambda Sagittarii
| Observation data Epoch J2000.0 Equinox J2000.0 |
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|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 27m 58.2s |
| Declination | -25° 25' 18" |
| Apparent magnitude (V) | +2.82 |
| Distance | 77.3 ± 1.6 ly (23.7 ± 0.5 pc) |
| Spectral type | K1+IIIb |
| Other designations | |
Lambda Sagittarii (λ Sgr, λ Sagittarii) is a star within the constellation Sagittarius. The star marks the top of the Archer's bow, whence its traditional name Kaus Borealis. It also marks the top of the lid of the so-called "Teapot" asterism. In ancient Chinese astronomy, it is the 2nd of 6 stars in the Dipper or 'South Dipper' mansion of the Black Tortoise of the North.
Kaus Borealis is a spectral class K orange giant star. It is currently fusing helium into carbon and oxygen in its core. Kaus Borealis is 77 light years from us, with a mass 2.6 times that of the Sun.[1] It is 52 times more luminous than the Sun and has a radius of some 11 Suns.
Being near the ecliptic, Lambda Sgr is sometimes occulted by the Moon and, more rarely, by a planet. The last planet to pass in front of it was Venus, on 19 November 1984. The previous occasion was on 5 December 1865, when it was occulted by the planet Mercury.
[edit] Etymology
The name Kaus Borealis comes from the Arabic قوس qaws 'bow' and Latin boreālis 'northern'. To the south of it lie the other stars of the bow, Kaus Media and Kaus Australis.
[edit] References
- ^ Edvardsson, B. (January 1988), "Spectroscopic surface gravities and chemical compositions for 8 nearby single sub-giants", Astronomy and Astrophysics 190 (1-2): 148–166, Bibcode 1988A&A...190..148E
[edit] External links
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