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)[13] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[14] included a table of the first two batches of names approved by the WGSN, which included Shaula for the star λ Scorpii Aa1.
In Indian astronomy, it is part of the asterism Mula with other stars in the tail of Scorpius. Mūla ("root") (Devanagari मूल/मूळ) (Tamil: மூலம்) is the 19th nakshatra or "lunar mansion" in Vedic astrology. The symbol of Mula is a bunch of roots tied together (reticulated roots) or an 'elephant goad' (ankusha).[15]
Together with υ Scorpii (Lesath), Shaula is listed in the Babylonian compendium MUL.APIN as dSharur4 u dShargaz, meaning "Sharur and Shargaz".[18] In Coptic, these two stars were called Minamref.[19]
The indigenous Boorong people of northwestern Victoria (Australia) named it (together with Upsilon Scorpii) Karik Karik,[20] "the Falcons".[21]
Properties
A light curve for Lambda Scorpii, plotted from TESS data.[22] The large dips in brightness are eclipses, and the rapid oscillations show the Beta Cephei variability.
Lambda Scorpii is located approximately 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.[6] The primary star is a Beta Cephei variable star with rapid brightness changes of about a hundredth of a magnitude.[7][5] The pre-main-sequence star has an orbital period of 6 days and the B-type companion has a period of 1,053 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-type 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. Gaia Data Release 3 reports that the fainter of these two stars is a little larger and brighter than the sun and about 420 light years away,[23] while the brighter star is a background object.[24]
^Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN978-1-931559-44-7.
^Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355. Bibcode:2000A&A...355L..27H.
^ abHamdy, 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 (1): 53–107. Bibcode:1993Ap&SS.203...53H. doi:10.1007/BF00659414. S2CID122459090.
^"Lambda Sco". International Variable Star Index. AAVSO. Retrieved 2025-08-20.
^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.
^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.
