Epsilon Herculis

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Epsilon Herculis
Hercules constellation map visualization.PNG
Cujam is the ε star in Keystone asterism in the Hercules constellation.
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 17h 00m 17.3738s[1]
Declination 30° 55′ 35.057″[1]
Apparent magnitude (V) 3.9111[2]
Spectral type A0 V[1]
U−B color index -0.12
B−V color index -0.03
Radial velocity (Rv) -25.1[1] km/s
Proper motion (μ) RA: -47.68[1] mas/yr
Dec.: 26.89[1] mas/yr
Parallax (π) 21.04 ± 0.14[2] mas
Distance 155 ± 1 ly
(47.5 ± 0.3 pc)
Absolute magnitude (MV) +0.54[3]
Mass 2.6±0.1[4] M
Radius 2.72±0.07[5] R
Luminosity 64[3] L
Surface gravity (log g) 3.98±0.02[5] cgs
Temperature 10197±57[5] K
Metallicity [Fe/H] −0.25±0.04[3] dex
Age 400+50
[4] Myr
Other designations
Cujam, Cajam, Caiam, Kajam, ε Her, 58 Her, BD +31° 2947, FK5 634, GC 22935, HD 153808, HIP 83207, HR 6324, SAO 65716.
Database references

Epsilon Herculis, Latinized from ε Herculis, is a fourth-magnitude spectroscopic binary star in the constellation Hercules. It has the traditional name Cujam.[citation needed]

In Chinese, 天紀 (Tiān Jì), meaning Celestial Discipline, refers to an asterism consisting of ε Herculis, ξ Coronae Borealis, ζ Herculis, 59 Herculis, 61 Herculis, 68 Herculis, HD 160054 and θ Herculis.[6] Consequently, ε Herculis itself is known as 天紀三 (Tiān Jì sān, English: the Third Star of Celestial Discipline.)[7]

See also[edit]


  1. ^ a b c d e f "SIMBAD query result:eps Her -- Spectroscopic binary". Centre de Données astronomiques de Strasbourg. Retrieved 2010-09-28. 
  2. ^ a b van Leeuwen, F. (November 2007), "Hipparcos, the New Reduction", Astronomy and Astrophysics, Centre de Données astronomiques de Strasbourg, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357, retrieved 2010-09-28 
  3. ^ a b c Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, Bibcode:2012AstL...38..331A, arXiv:1108.4971Freely accessible, doi:10.1134/S1063773712050015. 
  4. ^ a b Janson, Markus; et al. (August 2011), "High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood", The Astrophysical Journal, 736 (2): 89, Bibcode:2011ApJ...736...89J, arXiv:1105.2577Freely accessible, doi:10.1088/0004-637X/736/2/89 
  5. ^ a b c Fitzpatrick, E. L.; Massa, D. (March 2005), "Determining the Physical Properties of the B Stars. II. Calibration of Synthetic Photometry", The Astronomical Journal, 129 (3): 1642–1662, Bibcode:2005AJ....129.1642F, arXiv:astro-ph/0412542Freely accessible, doi:10.1086/427855 
  6. ^ (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.
  7. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 26 June 2006 天文教育資訊網 2006 年 6 月 26 日

External links[edit]

Coordinates: Sky map 17h 00m 17.3738s, +30° 55′ 35.06″