Kappa Herculis

Kappa Herculis (κ Herculis, abbreviated Kappa Her, κ Her) is an optical double star in the constellation of Hercules. The two components, Kappa Herculis A (Marsic /ˈmɑːrsɪk/, the traditional name of the system)^[15] and B, were 27.3 arc seconds apart in 2000. Based on parallax measurements from the Hipparcos mission, κ Her A is about 113 parsecs (370 light-years) from the Sun and κ Her B is 600 parsecs (2,000 light-years); more recent parallax measurements suggest that B is around 5% more distant than A.

κ Herculis

Historical view of the Hercules constellation showing Marfik (κ Her) as the hero's left "elbow".
Observation data Epoch J2000      Equinox J2000
Constellation	Hercules
κ Her A
Right ascension	16h 08m 04.52481s[1]
Declination	17° 02′ 49.1150″[1]
Apparent magnitude (V)	4.994[2]
κ Her B
Right ascension	16h 08m 04.95406s[3]
Declination	17° 03′ 15.6853″[3]
Apparent magnitude (V)	6.25[4]
Characteristics
Spectral type	G7III + K0IV[5]
U−B color index	+0.630[citation needed]
B−V color index	+0.931[citation needed]
Variable type	suspected[6]
Astrometry
κ Her A
Radial velocity (Rv)	−10.50[7] km/s
Proper motion (μ)	RA: −34.062[8] mas/yr Dec.: −6.585[8] mas/yr
Parallax (π)	8.5601 ± 0.1338 mas[8]
Distance	381 ± 6 ly (117 ± 2 pc)
Absolute magnitude (MV)	-45[9]
κ Her B
Radial velocity (Rv)	+32.21[10] km/s
Proper motion (μ)	RA: −19.465[11] mas/yr Dec.: −25.142[11] mas/yr
Parallax (π)	8.1307 ± 0.0502 mas[11]
Distance	401 ± 2 ly (123.0 ± 0.8 pc)
Details
κ Her A
Mass	3.17[12] M☉
Radius	16[8] R☉
Luminosity	148[9] L☉
Surface gravity (log g)	2.90[12] cgs
Temperature	5,119[12] K
Metallicity [Fe/H]	+0.04[12] dex
Rotational velocity (v sin i)	9.9[13] km/s
Age	309[9] Myr
κ Her B
Radius	11[11] R☉
Luminosity	55[11] L☉
Temperature	4,750[11] K
Metallicity [Fe/H]	+0.131[14] dex
Rotational velocity (v sin i)	1.0[13] km/s
Other designations
Marsic, κ Her, 7 Herculis, CCDM J16081+1703, NSV 7471, AAVSO 1603+17, WDS 16081+1703
A: HR 6008, HD 145001, HIP 79043, BD +77°2964
B: HR 6009, HD 145000, HIP 79045, BD +77°2965
Database references
SIMBAD	κ Her
	κ Her A
	κ Her B

A faint third component Kappa Herculis C is just over 1 arc-minute away.^[16] It is at the same distance as κ Her A and has an almost-identical space motion.^[17]

The star 8 Herculis forms a naked eye pair with Kappa Herculis 14′ away.

Nomenclature

κ Herculis (Latinised to Kappa Herculis) is the system's Bayer designation. The designations of the components as Kappa Herculis A, B and C derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).^[18]

The system bore the traditional names of "Marsic", "Marfik" or "Marfak", all of which come from the Arabic لمرفق Al-Mirfaq meaning "the elbow",^[19] a name (or some derivative of which) it shared with Lambda Ophiuchi. The Working Group on Star Names (WGSN) approved the name Marsic for the component Kappa Herculis A on February 1, 2017, and Marfik for the primary component of Lambda Ophiuchi on September 12, 2016, and they are both now so included in the List of IAU-approved Star Names.^[20]

In Chinese, 天市右垣 (Tiān Shì Yòu Yuán), meaning Right Wall of Heavenly Market Enclosure, refers to an asterism which represents eleven old states in China and marks the right borderline of the enclosure, consisting of Kappa Herculis, Beta Herculis, Gamma Herculis, Gamma Serpentis, Beta Serpentis, Delta Serpentis, Alpha Serpentis, Epsilon Serpentis, Delta Ophiuchi, Epsilon Ophiuchi and Zeta Ophiuchi.^[21] Consequently, the Chinese name for Kappa Herculis itself is 天市右垣三 (Tiān Shì Yòu Yuán sān, English: the Third Star of Right Wall of Heavenly Market Enclosure), representing the state of Jin (晉) (or Tsin),^[22][23] together with 36 Capricorni in Twelve States (asterism).^[24]

Properties

Kappa Herculis A is a giant star with stellar classification G8III. With a mass of three M_☉ and radius that is 16 R_☉, the star boasts a bolometric luminosity that is 148 L_☉. Its slightly companion is cooler and about a third of the luminosity.

Kappa Herculis is a suspected variable star with a reported magnitude range of 4.70 to 5.02.^[6]

References

1. van Leeuwen, F (November 2007). "Hipparcos, the New Reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Retrieved 2010-09-26.
2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H.
3. van Leeuwen, F (November 2007). "Hipparcos, the New Reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Retrieved 2010-09-26.
4. Argue, A. N. (1963). "UBV photometry of 300 G and K type stars". Monthly Notices of the Royal Astronomical Society. 125 (6): 557–570. Bibcode:1963MNRAS.125..557A. doi:10.1093/mnras/125.6.557.
5. Abt, H. A. (1981). "Visual multiples. VII - MK classifications". Astrophysical Journal Supplement Series. 45: 437. Bibcode:1981ApJS...45..437A. doi:10.1086/190719.
6. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
7. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
8. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
9. Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (2008). "Stellar Parameters and Elemental Abundances of Late-G Giants". Publications of the Astronomical Society of Japan. 60 (4): 781–802. arXiv:0805.2434. Bibcode:2008PASJ...60..781T. doi:10.1093/pasj/60.4.781. S2CID 16258166.
10. Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165–186. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
11. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
12. Liu, Y. J.; Tan, K. F.; Wang, L.; Zhao, G.; Sato, Bun'ei; Takeda, Y.; Li, H. N. (2014). "The Lithium Abundances of a Large Sample of Red Giants". The Astrophysical Journal. 785 (2): 94. arXiv:1404.1687. Bibcode:2014ApJ...785...94L. doi:10.1088/0004-637x/785/2/94.
13. De Medeiros, J. R.; Do Nascimento, J. D.; Sankarankutty, S.; Costa, J. M.; Maia, M. R. G. (2000). "Rotation and lithium in single giant stars". Astronomy and Astrophysics. 363: 239. arXiv:astro-ph/0010273. Bibcode:2000A&A...363..239D.
14. Franchini, M.; Morossi, C.; Di Marcantonio, P.; Malagnini, M. L.; Chavez, M.; Rodríguez-Merino, L. (2004). "Synthetic Lick Indices and Detection of α-enhanced Stars. II. F, G, and K Stars in the -1.0 < [Fe/H] < +0.50 Range". The Astrophysical Journal. 613 (1): 312. Bibcode:2004ApJ...613..312F. doi:10.1086/422909.
15. Davis, George A. (1944). "The pronunciations, derivations, and meanings of a selected list of star names". Popular Astronomy. 52: 8–30. Bibcode:1944PA.....52....8D.
16. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
17. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
18. Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
19. Kurt Vonnegut. "Constellations: Hercules 'the Strongman'". The BBC (British Broadcasting Corporation). Retrieved 2010-11-14.
20. "Naming Stars". IAU.org. Retrieved 16 December 2017.
21. (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.
22. (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-30 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
23. (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived 2008-09-24 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
24. Star Names - R.H.Allen p.142

External links

• Jim Kaler's Stars, University of Illinois: MARSIC (Kappa Herculis)
• Hercules constellation map showing: κ Herculis