Lambda Scorpii is a triple

star system A star system or stellar system is a small number of stars that orbit each other, bound by gravity, gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally calle ...

and the second-brightest object in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

of Scorpius. It is formally named Shaula; ''Lambda Scorpii'' is its

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

, which is Latinised from λ Scorpii and abbreviated Lambda Sco or λ Sco. With an apparent visual magnitude of 1.62, it is one of the brightest stars in the

night sky The night sky is the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon. Natural light sources in a night sky include moonlig ...

Nomenclature

''λ Scorpii'' (Latinised to ''Lambda Scorpii'') is the star system's

. It bore the traditional name ''Shaula'', which comes from the

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

الشولاء ''al-šawlā´'' meaning 'the raised ail, as it is found in the tail of Scorpius, the scorpion. In 2016, the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included ''Shaula'' for the star λ Scorpii Aa. In Indian Astronomy it is called MulA Nakshathram. 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). In Chinese, (), meaning ''

Tail The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to los ...

'', 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. Consequently, the Chinese name for λ Scorpii itself is (), "the Eighth Star of Tail". Together with υ Scorpii (Lesath), Shaula is listed in the Babylonian compendium MUL.APIN as ^dSharur₄ u ^dShargaz, meaning "Sharur and Shargaz". In Coptic, they were called ''Minamref''. The indigenous Boorong people of northwestern

Victoria (Australia) Victoria, commonly abbreviated as Vic, is a States and territories of Australia, state in southeastern Australia. It is the second-smallest state (after Tasmania), with a land area of ; the second-most-populated state (after New South Wales), ...

named it (together with Upsilon Scorpii) ''Karik Karik'', "the Falcons".

Properties

Lambda Scorpii is located some 570

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s away from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

. Spectroscopic and interferometric observations have shown that it is actually a triple

consisting of two B-type stars and a

pre-main-sequence star A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence. Earlier in its life, the object is a protostar that grows by acquiring mass from its surrounding envelope o ...

. The primary star is a Beta Cephei variable star with rapid brightness changes of about a hundredth of a magnitude. 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 mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...

es, 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 unit The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its m ...

s (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, while the brighter star is a background object.

In culture

Shaula appears on the

flag of Brazil The national flag of Brazil is a blue disc depicting a starry sky (which includes the Crux, Southern Cross) spanned by a curved band inscribed with the List of national mottos, national motto ('Order and Progress'), within a yellow rhombus, on ...

, symbolizing the state of

Rio Grande do Norte Rio Grande do Norte (, , ) is one of the states of Brazil. It is located in the northeastern region of the country, forming the northeasternmost tip of the South American continent. The name literally translates as "Great Northern River", refe ...

. USS ''Shaula'' (AK-118) was a U.S. Navy ''Crater''-class cargo ship named after the star.

References

{{Sky, 17, 33, 36.520, -, 37, 06, 13.76 B-type subgiants Beta Cephei variables 5 Scorpius Scorpii, Lambda 6527 Durchmusterung objects Scorpii, 35 158926 085927 Shaula