Magnitude 3.126 Apparent magnitude (V) 3.126 | Constellation Hercules | |
 | ||
Similar Kappa Herculis, Pi Herculis, Lambda Herculis, Mu Herculis, Zeta Herculis | ||
Delta Herculis (δ Herculis, abbreviated Delta Her, δ Her), also named Sarin, is a third-magnitude multiple star in the constellation of Hercules.
Contents
Nomenclature
δ Herculis (Latinised to Delta Herculis) is the star's Bayer designation.
It bore the traditional name Sarin. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Sarin for this star on 12 September 2016 and it is now so entered in the IAU Catalog of Star Names.
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Menkib al Jathi al Aisr, which was translated into Latin as Humerus Sinister Ingeniculi, meaning the left shoulder of the kneeling man.
In Chinese, 天市左垣 (Tiān Shì Zuǒ Yuán), meaning Left Wall of Heavenly Market Enclosure, refers to an asterism which represents eleven old states in China which is marking the left borderline of the enclosure, consisting of Delta Herculis, Lambda Herculis, Mu Herculis, Omicron Herculis, 112 Herculis, Zeta Aquilae, Theta1 Serpentis, η, Nu Ophiuchi, Xi Serpentis and Eta Ophiuchi. Consequently, Delta Herculis itself is known as 天市左垣一 (Tiān Shì Zuǒ Yuán yī, English: the First Star of Left Wall of Heavenly Market Enclosure), and represents the state of Wei (魏), together with 33 Capricorni (Phi Capricorni and Chi Capricorni in R.H. Allen's version) in Twelve States (asterism).
Properties
Delta Herculis is a complex star system consisting of at least two stars and possibly as many as five. The main star is an A-type main-sequence subgiant with a stellar classification A3IV. The subgiant has both a mass and radius that are roughly two times solar yielding a total luminosity of about 18.5 L☉ Though it only shines with an apparent magnitude of 3.12, it the third-brightest star in the Hercules constellation. The most recent Hipparcos data yields a distance estimate of approximately 23.1 parsecs (75 light-years) from Earth.