Lambda Scorpii

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λ 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
Distanceapprox. 570 ly
(approx. 180 pc)
Absolute magnitude (MV)−3.70[7]
λ Sco A
Mass14.5±1.1[5] M
Radius8.8±1.2[5] R
Luminosity36,300[5] L
Surface gravity (log g)3.8[8] cgs
Temperature25,000±1,000[5] K
Rotational velocity (v sin i)150[5] km/s
λ Sco B
Mass9.6-11.6[5] M
Radius4.7±1.0[5] R
Surface gravity (log g)4.0[8] cgs
Temperature25,000±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

Lambda Scorpii (Latinised from λ Scorpii, abbreviated Lambda Sco, λ Sco), also called Shaula,[9] is, despite being designated "λ" (Lambda), the second-brightest star system in the constellation of Scorpius, and one of the brightest "stars" in the night sky.


λ Scorpii (Latinised to Lambda Scorpii) is the star system'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 Scorpius, the scorpion. 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 the star λ Scorpii Aa.

In Chinese, 尾宿 (Wěi Xiù), meaning Tail, refers to an asterism consisting of λ Scorpii, ε Scorpii, ζ1 Scorpii, ζ2 Scorpii, η Scorpii, θ Scorpii, ι1 Scorpii, ι2 Scorpii, κ Scorpii, μ1 Scorpii, and υ Scorpii.[12] Consequently, λ Scorpii itself is known as 尾宿八 (Wěi Xiù bā), "the Eighth Star of Tail".[13]

Together with υ Scorpii (Lesath), Shaula is listed in the Babylonian compendium MUL.APIN as dSharur4 u dShargaz, meaning "Sharur and Shargaz".[14]

In Coptic, they were called Minamref.[15]

The indigenous Boorong people of northwestern Victoria (Australia) named it (together with Upsilon Scorpii) as Karik Karik,[16] "the Falcons".[17]


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

Spectroscopic and interferometric observations have shown that it is actually a triple star 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][18] 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 7,500 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, symbolizing the state of Rio Grande do Norte.

USS Shaula (AK-118) was a U.S. 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:0708.1752. 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:1307.8047. 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:1307.2733. 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. arXiv:1606.08053. 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" (PDF). 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. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  13. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2008-10-25 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  14. ^ Rogers, J. H. (February 1998). "Origins of the ancient constellations: I. The Mesopotamian traditions". Journal of the British Astronomical Association. 108 (1): 9–28. Bibcode:1998JBAA..108....9R.
  15. ^ 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.
  16. ^ 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:1010.4610. Bibcode:2010JAHH...13..220H.
  17. ^ 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.
  18. ^ 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/0605311. Bibcode:2006MNRAS.370..884T. doi:10.1111/j.1365-2966.2006.10526.x.

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