Kappa Herculis

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Marfik, κ Her
Hercules Historical View.png
Historical view of the Hercules constellation showing Marfik (κ Her) as the hero's left "elbow".
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 16h 08m 04.5255s[1]
Declination 17° 02′ 49.129″[1]
Apparent magnitude (V) 5.1628[2]

Spectral type G8III [1]
U−B color index +0.630
B−V color index +0.931
Radial velocity (Rv) -11.0[1] km/s
Proper motion (μ) RA: -34.29[1] mas/yr
Dec.: -5.46[1] mas/yr
Parallax (π) 8.40 ± 1.23[3] mas
Distance approx. 390 ly
(approx. 120 pc)
Absolute magnitude (MV) -0.22
Mass 3.4[4] M
Radius ~16[5] R
Luminosity 150 [5] L
Temperature 4,990 [5][6] K
Metallicity −0.26 Fe/H[6]
Rotational velocity (v sin i) 10[7] km/s
Age ~4.0×108[5] years
Other designations
Marfik, Marfak, Marsic, κ Her, 7 Her A, HR 6008, BD +77° 2964, HD 145001, FK5 1421, HIP 79043, SAO 101951, GC 21696, CCDM J16081+1703A, AAVSO 1603+17
Database references

Coordinates: Sky map 16h 08m 04.526s, +17° 02′ 49.13″

Kappa Herculis (κ Her, κ Herculis) is a double star in the constellation Hercules. Traditional names that have been attributed to the star are "Marfik", "Marfak" or "Marsic", all of which come from the Arabic لمرفق Al-Mirfaq meaning "the elbow",[8] a name (or some derivative of which) it shares with Lambda Ophiuchi.


Kappa Herculis is a giant star with stellar classification G8III. With a mass of 3.0 M and radius that is 16 R, the star boasts a total bolometric luminosity that is 150 L.[5] Its apparent magnitude has been recently recalibrated at 5.1628.[2] The Hipparcos mission estimated its distance at roughly 120 parsecs from Earth, or 390 ± 20 light years away.


In Chinese, 天市右垣 (Tiān Shì Yòu Yuán), meaning Right Wall of Heavenly Market Enclosure, refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of κ Herculis, β Herculis, γ Herculis, γ Serpentis, β Serpentis, δ Serpentis, α Serpentis, ε Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi.[9] Consequently, κ Herculis itself is known as 天市右垣三 (Tiān Shì Yòu Yuán sān, English: the Third Star of Right Wall of Heavenly Market Enclosure), represent the state Jin (晉) (or Tsin).,[10][11] together with 36 Capricorni in Twelve States (asterism).[12]

See also[edit]


  1. ^ a b c d e f "SIMBAD query result: HR 6008 -- Star in double system". Centre de Données astronomiques de Strasbourg. Retrieved 2010-09-26. 
  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. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Retrieved 2010-09-26. 
  3. ^ Perryman, M. A. C.; et al. (1997), "The Hipparcos Catalogue", Astronomy & Astrophysics 323: L49–L52, Bibcode:1997A&A...323L..49P 
  4. ^ Gondoin, P. (December 1999), "Evolution of X-ray activity and rotation on G-K giants", Astronomy and Astrophysics 352: 217–227, Bibcode:1999A&A...352..217G 
  5. ^ a b c d e Kaler, James B. "MARSIC (Kappa Herculis)". University of Illinois. Retrieved 2010-09-26. 
  6. ^ a b McWilliam, Andrew (December 1990). "High-resolution spectroscopic survey of 671 GK giants" (PDF). Astrophysical Journal Supplement Series 74: 1075–1128. Bibcode:1990ApJS...74.1075M. doi:10.1086/191527. ISSN 0067-0049. 
  7. ^ "Bright Star Catalogue (Hoffleit+, 1991)". VizieR (5th Revised ed.). Centre de Données astronomiques de Strasbourg. Retrieved 2010-09-26. 
  8. ^ Kurt Vonnegut. "Constellations: Hercules 'the Strongman'". The BBC (British Broadcasting Corporation). Retrieved 2010-11-14. 
  9. ^ (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.
  10. ^ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
  11. ^ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name, Hong Kong Space Museum. Accessed on line November 23, 2010.
  12. ^ Star Names - R.H.Allen p.142

External links[edit]