Lambda Scorpii
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| Observation data Equinox J2000.0 |
|
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 33m 36.6s / 42.6s / 32.5s |
| Declination | -37° 06′ 13″ / -37° 06′ 44″ / -37° 04′ 52″ |
| Apparent magnitude (V) | 1.62 / 14.9 / 12.0 |
| Characteristics | |
| Spectral type | B1.5-2 IV+ (A) |
| U-B color index | -0.91 (A) |
| B-V color index | -0.23 (A) |
| Variable type | Beta Cephei (A) |
| Astrometry (component A) | |
| Radial velocity (Rv) | -3 km/s |
| Proper motion (μ) | RA: -8.90 mas/yr Dec.: -29.95 mas/yr |
| Parallax (π) | 4.64 ± 0.90 mas |
| Distance | 700 ± 100 ly (220 ± 40 pc) |
| Absolute magnitude (MV) | -5 |
| Other designations | |
| Data sources: | |
| CCDM (2002), Simbad |
|
Lambda Scorpii (λ Sco / λ Scorpii) is the second brightest star system in the constellation Scorpius, and one of the brightest stars in the nighttime sky. It has the Bayer designation λ despite being the second brightest in its constellation. It also has the traditional name Shaula, which comes from the Arabic الشولاء aš-šawlā´ meaning the raised [tail], as it is found in the tail of the scorpion (Scorpius). It is known as 尾宿八 (the Eighth Star of the Tail) in Chinese.
Lambda Scorpii is a multiple star with three visible components. The first, Lambda Scorpii A, is classified as a B-type subgiant. The 15th magnitude Lambda Scorpii B has a separation of 42 arcseconds from component A, while the 12th magnitude Lambda Scorpii C is 95 arcseconds from A. It is not known whether or not these components are physically associated with component A. If they both were, B would be approximately 7500 Astronomical Units and C approximately 17,000 AU (0.27 light years) from A.
Spectroscopic observations suggest that A is actually a system of three stars: two early-type B stars orbiting each other with a period of 6 days, and a low-mass pre-main sequence star, orbiting the pair with a period of 1100 days.[1]
[edit] References
- ^ Interpretation of the variability of the β Cephei star λ Scorpii. I. The multiple character, K. Uytterhoeven, B. Willems, K. Lefever, C. Aerts, J. H. Telting, and U. Kolb, Astronomy and Astrophysics 427 (2004), 581–592. Abstract on ADSABS
[edit] External links
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