Lambda Scorpii

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Lambda Scorpii
Scorpius constellation map.svg
Red circle.svg

Location of λ Scorpii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 17h 33m 36.520s[1]
Declination −37° 06′ 13.76″[1]
Apparent magnitude (V) 1.62 / 14.9 / 12.0[1][2]
Spectral type B2IV+DA7.9[3]
U−B color index −0.880[4]
B−V color index −0.240[4]
Variable type Beta Cephei (A)[5]
Radial velocity (Rv) −3.00[6] km/s
Proper motion (μ) RA: −8.90[1] mas/yr
Dec.: −29.95[1] mas/yr
Parallax (π) 5.71 ± 0.90[1] mas
Distance approx. 570 ly
(approx. 180 pc)
Absolute magnitude (MV) −3.70[7]
λ Sco A
Mass 14.5±1.1[5] M
Radius 8.8±1.2[5] R
Luminosity 36,300[5] L
Surface gravity (log g) 3.8[8] cgs
Temperature 25,000±1,000[5] K
Rotational velocity (v sin i) 150[5] km/s
λ Sco B
Mass 9.6-11.6[5] M
Radius 4.7±1.0[5] R
Surface gravity (log g) 4.0[8] cgs
Temperature 25,000±1,000[5] K
Other designations
Shaula, 35 Scorpii, 35 Sco, HR 6527, CD -37 11673, HD 158926, SAO 208954, FK5 652, HIP 85927, CCDM J17336-3706A/B/C.
Database references
Data sources:
CCDM (2002),

Lambda Scorpii (λ Scorpii, abbreviated Lambda Sco, λ Sco), also named Shaula,[9] is (despite being designated 'Lambda') the second brightest star system in the constellation of Scorpius, and one of the brightest stars in the nighttime sky.


λ Scorpii (Latinised to Lambda Scorpii) is the star's Bayer designation.

It bore the traditional name Shaula, which comes from the Arabic الشولاء al-šawlā´ meaning 'the raised [tail]', as it is found in the tail of the scorpion (Scorpius). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[11] included a table of the first two batches of names approved by the WGSN; which included Shaula for this star.

It is known as Wei Xiu Ba 尾宿八 (the Eighth Star of the Tail) in Chinese.

Together with Upsilon Scorpii (Lesath), Shaula is listed in the Babylonian compendium MUL.APIN as dSharur4 u dShargaz, meaning "Sharur and Shargaz".[12]

In Coptic, they were called Minamref.[13]

The indigenous Boorong people of northwestern Victoria named it (together with Upsilon Scorpii) as Karik Karik,[14] "the Falcons".[15]


Lambda Scorpii is located some 570 light years away from the Sun.

Spectroscopic and interferometric observations have shown that it is actually a triple system consisting of two B-type stars and a pre–main sequence star.[5] The primary star is a beta Cephei variable star with rapid brightness changes of about a hundredth of a magnitude.[8][16] The pre–main sequence star has an orbital period of 6 days and the B companion has a period of 1053 days. The three stars lie in the same orbital plane, strongly suggesting that they were formed at the same time. The masses of the primary, pre–main sequence star and the B companion are 14.5, 2.0 and 10.6 solar masses, respectively. The age of the system is estimated to be in the range 10–13 million years.

A 15th magnitude star has a separation of 42 arcseconds, whereas a 12th magnitude star is 95 arcseconds away. It is not known whether or not these components are physically associated with Lambda Scorpii. If they both were, the first would have a projected linear separation of approximately 7500 Astronomical units (AU) and the second approximately 17,000 AU (0.27 light years) away.

In culture[edit]

Shaula appears on the flag of Brazil, symbolising the state of Rio Grande do Norte.

USS Shaula (AK-118) was a United States Navy Crater class cargo ship named after the star.

See also[edit]


  1. ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752free to read. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ Reed, B. Cameron (2003), "Catalog of Galactic OB Stars", The Astronomical Journal, 125 (5): 2531–2533, Bibcode:2003AJ....125.2531R, doi:10.1086/374771. 
  3. ^ Holberg, J. B.; Oswalt, T. D.; Sion, E. M.; Barstow, M. A.; Burleigh, M. R. (2013). "Where are all the Sirius-like binary systems?". Monthly Notices of the Royal Astronomical Society. 435 (3): 2077. arXiv:1307.8047free to read. Bibcode:2013MNRAS.435.2077H. doi:10.1093/mnras/stt1433. 
  4. ^ a b Hamdy, M. A.; Abo Elazm, M. S.; Saad, S. M. (1993). "A catalogue of spectral classification and photometric data of B-type stars". Astrophysics and Space Science. 203: 53. Bibcode:1993Ap&SS.203...53H. doi:10.1007/BF00659414. 
  5. ^ a b c d e f g h i j Handler, G.; Schwarzenberg-Czerny, A. (2013). "Time-resolved multicolour photometry of bright B-type variable stars in Scorpius". Astronomy & Astrophysics. 557: A1. arXiv:1307.2733free to read. Bibcode:2013A&A...557A...1H. doi:10.1051/0004-6361/201321886. 
  6. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. 
  7. ^ Balona, L. A.; Feast, M. W. (1975). "The luminosities of the beta Canis Majoris variables, the zero age main sequence and the distance of the Sco-Cen association". Monthly Notices of the Royal Astronomical Society. 172: 191. Bibcode:1975MNRAS.172..191B. doi:10.1093/mnras/172.1.191. 
  8. ^ a b c Uytterhoeven, K.; Willems, B.; Lefever, K.; Aerts, C.; Telting, J. H.; Kolb, U. (2004). "Interpretation of the variability of the β Cephei star λ Scorpii". Astronomy and Astrophysics. 427 (2): 581–592. Bibcode:2004A&A...427..581U. doi:10.1051/0004-6361:20041223. 
  9. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016. 
  10. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016. 
  11. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016. 
  12. ^ Rogers, J. H. (February 1998). "Origins of the ancient constellations: I. The Mesopotamian traditions". Journal of the British Astronomical Association, no.1. 108: 9–28. Bibcode:1998JBAA..108....9R. 
  13. ^ p. 1678, Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System, Volume 3, Robert Burnham, New York, Dover Publication, Inc, 1978.
  14. ^ Hamacher, Duane W.; Frew, David J. (2010). "An Aboriginal Australian Record of the Great Eruption of Eta Carinae". Journal of Astronomical History and Heritage. 13 (3): 220–34. arXiv:1010.4610free to read. Bibcode:2010JAHH...13..220H. 
  15. ^ Stanbridge, William Edward (1857). "On the astronomy and mythology of the Aborigines of Victoria". Proceedings of the Philosophical Institute of Victoria. 2: 137. Bibcode:1857PPIVT...2..137S. 
  16. ^ Tango, W. J.; Davis, J.; Ireland, M. J.; Aerts, C.; Uytterhoeven, K.; Jacob, A. P.; Mendez, A.; North, J. R.; Seneta, E. B.; Tuthill, P. G. (2006). "Orbital elements, masses and distance of λ Scorpii a and B determined with the Sydney University Stellar Interferometer and high-resolution spectroscopy". Monthly Notices of the Royal Astronomical Society. 370 (2): 884. arXiv:astro-ph/0605311free to read. Bibcode:2006MNRAS.370..884T. doi:10.1111/j.1365-2966.2006.10526.x. 

Coordinates: Sky map 17h 33m 36.520s, −37° 06′ 13.76″