111 Herculis
Star in the constellation Hercules
From Wikipedia, the free encyclopedia
111 Herculis is a suspected astrometric binary[8] star system located 92 light years from the Sun in the northern constellation Hercules. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.34.[2] The system is moving nearer to the Earth with a heliocentric radial velocity of −45 km/s, and may come as close as 37 light-years in 537,000 years.[2]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 47m 01.23431s[1] |
| Declination | +21° 46′ 53.4578″[1] |
| Apparent magnitude (V) | 4.34[2] |
| Characteristics | |
| Evolutionary stage | main sequence[1] |
| Spectral type | A3Va+[3] |
| B−V color index | 0.148±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | −44.6±2.7[2] km/s |
| Proper motion (μ) | RA: +98.835[1] mas/yr Dec.: +115.120[1] mas/yr |
| Parallax (π) | 34.9987±0.1743 mas[1] |
| Distance | 93.2 ± 0.5 ly (28.6 ± 0.1 pc) |
| Absolute magnitude (MV) | 2.04[2] |
| Details | |
| Mass | 2.40[4] M☉ |
| Radius | 1.6[5] R☉ |
| Luminosity | 12.84[2] L☉ |
| Surface gravity (log g) | 4.35[4] cgs |
| Temperature | 8,873±302[4] K |
| Metallicity [Fe/H] | 0.33[6] dex |
| Rotational velocity (v sin i) | 71[4] km/s |
| Age | 559[4] Myr |
| Other designations | |
| 111 Her, BD+18°3823, FK5 1491, HD 173880, HIP 92161, HR 7069, SAO 104093, WDS J18470+1811[7] | |
| Database references | |
| SIMBAD | data |
According to Garrison (1989), the visible component has a spectral classification if A3Va+, indicating an A-type main sequence star. Other authors have published classes of A5III,[9] matching an A-type giant star, and A3IV, suggesting it is instead a subgiant star.[10] Models of the star's evolution suggest that it is still on the main sequence.[1]
The interferometry-measured angular diameter of the primary component is 0.52±0.02 mas,[11] which, at its estimated distance, equates to a physical radius of roughly 1.6 times the radius of the Sun.[5] The star is estimated to be 559[4] million years old with 2.40[4] times the mass of the Sun and is spinning with a projected rotational velocity of 71 km/s.[4] It is radiating 13 times the Sun's luminosity from its photosphere at an effective temperature of 8,873 K.[4]
