106 Herculis
Binary star system in the constellation Hercules
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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]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 20m 17.91482s[2] |
| Declination | +21° 57â² 40.6622â³[2] |
| Apparent magnitude (V) | 4.96[3] |
| Characteristics | |
| Spectral type | M0 III[4] |
| UâB color index | +1.98[5] |
| BâV color index | +1.58[5] |
| Variable type | suspected SR[6][7] |
| Astrometry | |
| Radial velocity (Rv) | â35.20±0.29[8] km/s |
| Proper motion (μ) | RA: +18.105[2] mas/yr Dec.: -59.631[2] mas/yr |
| Parallax (Ï) | 8.5067±0.1739 mas[2] |
| Distance | 383 ± 8 ly (118 ± 2 pc) |
| Absolute magnitude (MV) | â0.664[8] |
| Details | |
| Radius | 44.32+2.70 â5.89[2] Râ |
| Luminosity | 414.1±9.7[2] Lâ |
| 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 |
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]