Delta Herculis

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Delta Herculis
Hercules Historical View.png
Historical view of the Hercules constellation showing the star Sarin (δ Her) next to the Keystone asterism.
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 17h 15m 01.9106s[1]
Declination 24° 50′ 21.135″[1]
Apparent magnitude (V) 3.126[1]
Spectral type A3IV[1]
U−B color index +0.7[2]
B−V color index +0.08[2]
Radial velocity (Rv) -40.0[1] km/s
Proper motion (μ) RA: -21.14[1] mas/yr
Dec.: -157.68[1] mas/yr
Parallax (π) 43.41 ± 0.15[3] mas
Distance 75.1 ± 0.3 ly
(23.04 ± 0.08 pc)
Absolute magnitude (MV) +1.31
Mass 2.4[4] M
Radius 2.2[4] R
Luminosity 38[4] L
Temperature 9,620 ± 350[4] K
Rotational velocity (v sin i) 270[5] km/s
Age 370[5] Myr
Other designations
Sarin, δ Her, 65 Her, BD 25° 3221, CCDM J17151+2451A, FK5 641, GC 23294, HD 156164, HIP 84379, HR 6410, SAO 84951.
Database references

Delta Herculis (δ Herculis, abbreviated Delta Her, δ Her), also named Sarin,[6] is a third-magnitude multiple star in the constellation of Hercules.


δ Herculis (Latinised to Delta Herculis) is the star's Bayer designation.

It bore the traditional name Sarin.[7][8] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[9] 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.[6]

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.[10]

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.[11] 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),[12][13] together with 33 Capricorni (Phi Capricorni and Chi Capricorni in R.H. Allen's version)[14] 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[5] 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.

See also[edit]


  1. ^ a b c d e f g "del Her -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2010-11-17 
  2. ^ a b Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished) (PDF), SIMBAD, Bibcode:1986EgUBV........0M, retrieved 2013-12-10 
  3. ^ van Leeuwen, F. (November 2007). "Hipparcos, the New Reduction". Astronomy and Astrophysics. Centre de Données astronomiques de Strasbourg. 474 (2): 653. Bibcode:2007A&A...474..653V. arXiv:0708.1752Freely accessible. doi:10.1051/0004-6361:20078357. 
  4. ^ a b c d 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 
  5. ^ a b c Kaler, James B., "DELTA HER (Delta Herculis)", Stars, University of Illinois, retrieved 2010-11-17 
  6. ^ a b "IAU Catalog of Star Names". Retrieved 28 July 2016. 
  7. ^ Vonnegut, Kurt, Constellations: Hercules 'the Strongman', The BBC (British Broadcasting Corporation), retrieved 2010-11-17 
  8. ^ δ Her (Sarin),, retrieved 2010-11-17 
  9. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016. 
  10. ^ 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 
  11. ^ (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.
  12. ^ (in 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.
  13. ^ (in 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.
  14. ^ Star Names - R.H.Allen p.142

External links[edit]

Coordinates: Sky map 17h 15m 01.910s, +24° 50′ 21.135″