Epsilon Herculis

Epsilon Herculis

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]
Characteristics
Spectral type A0 V[1]
U−B color index -0.12
B−V color index -0.03
Astrometry
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
Distance155 ± 1 ly
(47.5 ± 0.3 pc)
Absolute magnitude (MV)0.53
Details
Mass2.6±0.1[3] M☉
Radius2.72±0.07[4] R☉
Surface gravity (log g)3.98±0.02[4] cgs
Temperature10197±57[4] K
Age400+50
−40[3] 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
SIMBADdata

Epsilon Herculis (ε Her, ε Herculis) is a fourth-magnitude spectroscopic binary star in the constellation Hercules. It has the traditional name Cujam.

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.[5] Consequently, ε Herculis itself is known as 天紀三 (Tiān Jì sān, English: the Third Star of Celestial Discipline.)[6]

See also

References

  1. 1 2 3 4 5 6 "SIMBAD query result:eps Her -- Spectroscopic binary". Centre de Données astronomiques de Strasbourg. Retrieved 2010-09-28.
  2. 1 2 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:0708.1752 Freely accessible, doi:10.1051/0004-6361:20078357, retrieved 2010-09-28
  3. 1 2 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:1105.2577 Freely accessible, doi:10.1088/0004-637X/736/2/89
  4. 1 2 3 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/0412542 Freely accessible, doi:10.1086/427855
  5. ↑ (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.
  6. ↑ (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

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

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