| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 20m 17.91482s [2] |
| Declination | +21° 57′ 40.6622″ [2] |
| Apparent magnitude (V) | 4.96 [3] |
| Characteristics | |
| Spectral type | M0 III [4] |
| U−B color index | +1.98 [5] |
| B−V color index | +1.58 [5] |
| Variable type | suspected SR [6] [7] |
| Astrometry | |
| Radial velocity (Rv) | −35.20±0.29 [8] km/s |
| Proper motion (μ) | RA: +18.105 [2] mas/yr Dec.: -59.631 [2] mas/yr |
| Parallax (π) | 8.5067±0.1739 mas [2] |
| Distance | 383 ± 8 ly (118 ± 2 pc) |
| Absolute magnitude (MV) | −0.664 [8] |
| Details | |
| Radius | 44.32+2.70 −5.89 [2] R☉ |
| Luminosity | 414.1±9.7 [2] L☉ |
| Surface gravity (log g) | 1.56±0.09 [4] cgs |
| Temperature | 3,789±6 [4] K |
| Metallicity [Fe/H] | 0.00±0.03 [4] dex |
| Rotational velocity (v sin i) | 5.0±1.0 [9] km/s |
| Other designations | |
| 106 Her, NSV 24405, BD+21°3390, HD 168720, HIP 89861, HR 6868, SAO 85941 [10] | |
| Database references | |
| SIMBAD | data |
106 Herculis is a variable star in the northern constellation Hercules. It is visible to the naked eye as a faint, red-hued point of light with a baseline apparent visual magnitude of 4.96. [3] Based on its parallax, it is estimated to lie 383 light-years (117 parsecs) away from the Sun. [4] The star is moving closer to the Earth with a heliocentric radial velocity of -35 km/s. [8]
Eggleton and Tokovinin (2008) listed this as a suspected binary star system consisting of two roughly equal components. [11] It appears as an ageing red giant with a stellar classification of M0III. This is a suspected semiregular variable star with a very small amplitude and a period of 40 days or more. [7] Having exhausted the supply of hydrogen at its core, it has expanded to 44 times the Sun's radius. [2] It is radiating around 414 times the luminosity of the Sun [2] from its enlarged photosphere at an effective temperature of about 3,789 K . [4]
