Epoch J2000 Equinox J2000
|Right ascension||17h 15m 01.9106s|
|Declination||24° 50′ 21.135″|
|Apparent magnitude (V)||3.126|
|U−B color index||+0.7|
|B−V color index||+0.08|
|Radial velocity (Rv)||-40.0 km/s|
|Proper motion (μ)||RA: -21.14 mas/yr
Dec.: -157.68 mas/yr
|Parallax (π)||43.41 ± 0.15 mas|
|Distance||75.1 ± 0.3 ly
(23.04 ± 0.08 pc)
|Absolute magnitude (MV)||+1.31|
|Temperature||9,620 ± 350 K|
|Rotational velocity (v sin i)||270 km/s|
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).
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.
- "del Her -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2010-11-17
- Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished) (PDF), SIMBAD, Bibcode:1986EgUBV........0M, retrieved 2013-12-10
- van Leeuwen, F. (November 2007). "Hipparcos, the New Reduction". Astronomy and Astrophysics. Centre de Données astronomiques de Strasbourg. 474 (2): 653. arXiv: . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- Malagnini, M. L.; Morossi, C. (November 1990), "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars", Astronomy and Astrophysics Supplement Series, 85 (3): 1015–1019, Bibcode:1990A&AS...85.1015M
- Kaler, James B., "DELTA HER (Delta Herculis)", Stars, University of Illinois, retrieved 2010-11-17
- "IAU Catalog of Star Names". Retrieved 28 July 2016.
- Vonnegut, Kurt, Constellations: Hercules 'the Strongman', The BBC (British Broadcasting Corporation), retrieved 2010-11-17
- δ Her (Sarin), Wikisky.org, retrieved 2010-11-17
- IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
- Knobel, E. B. (June 1895), "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket", Monthly Notices of the Royal Astronomical Society, 55: 429, Bibcode:1895MNRAS..55..429K, doi:10.1093/mnras/55.8.429
- (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.
- (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived September 29, 2009, at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
- (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived August 10, 2010, at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
- Star Names - R.H.Allen p.142
- Jim Kaler's Stars, University of Illinois: DELTA HER (Delta Herculis)
- An Atlas of the Universe: Multiple Star Orbits