Epsilon Herculis

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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]
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
Distance 155 ± 1 ly
(47.5 ± 0.3 pc)
Absolute magnitude (MV) 0.53
Details
Mass 2.6 ± 0.1[3] M
Radius 2.72 ± 0.07[4] R
Surface gravity (log g) 3.98 ± 0.02[4] cgs
Temperature 10,197 ± 57[4] K
Age 400+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
SIMBAD data

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[edit]

References[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; VizieR (Centre de Données astronomiques de Strasbourg) 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, retrieved 2010-09-28 
  3. ^ 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, arXiv:1105.2577, Bibcode:2011ApJ...736...89J, doi:10.1088/0004-637X/736/2/89 
  4. ^ 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, arXiv:astro-ph/0412542, Bibcode:2005AJ....129.1642F, doi:10.1086/427855 
  5. ^ (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. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 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″