Kappa Herculis
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Hercules |
| κ Her A | |
| Right ascension | 16h 08m 04.52481s |
| Declination | 17° 02′ 49.1150″ |
| Apparent magnitude (V) | 4.994 |
| κ Her B | |
| Right ascension | 16h 08m 04.95406s |
| Declination | 17° 03′ 15.6853″ |
| Apparent magnitude (V) | 6.25 |
| Characteristics | |
| Spectral type | G7III + K0IV |
| U−B color index | +0.630 |
| B−V color index | +0.931 |
| Variable type | suspected |
| Astrometry | |
| κ Her A | |
| Radial velocity (Rv) | -10.50 km/s |
| Proper motion (μ) |
RA: -35.55 mas/yr Dec.: -7.04 mas/yr |
| Parallax (π) | 8.87 ± 0.55mas |
| Distance | 370 ± 20 ly (113 ± 7 pc) |
| Absolute magnitude (MV) | -0.22 |
| κ Her B | |
| Radial velocity (Rv) | +32.21 km/s |
| Proper motion (μ) |
RA: -25.70 mas/yr Dec.: -39.45 mas/yr |
| Parallax (π) | 1.55 ± 1.98mas |
| Distance | approx. 2,000 ly (approx. 600 pc) |
| Details | |
| κ Her A | |
| Mass | 3.4 M☉ |
| Radius | ~16 R☉ |
| Luminosity | 150 L☉ |
| Temperature | 4,990 K |
| Metallicity [Fe/H] | −0.26 dex |
| Rotational velocity (v sin i) | 10 km/s |
| Age | ~4.0×108 years |
| Other designations | |
| 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 | |
Coordinates: 
16h 08m 04.526s, +17° 02′ 49.13″
Kappa Herculis (κ Her, κ Herculis) is a double star in the constellation Hercules. κ Herculis A has the proper name Marsic.
Kappa Herculis A 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☉. The Hipparcos mission estimated its distance at roughly 120 parsecs from Earth, or 390 ± 20 light years away.
There is a faint third component κ Herculis C just over 1 arc-minute away. The star 8 Herculis forms a naked-eye pair with κ Herculis.
κ Herculis is a suspected variable star with a reported magnitude range of 4.70 to 5.02.
κ Herculis (Latinised to Kappa Herculis) is the system's Bayer designation.
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", a name (or some derivative of which) it shares with Lambda Ophiuchi. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Marsic for Kappa Herculis A on February 1, 2017 and it is now so entered in the IAU Catalog of Star Names.
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