102 Herculis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 08m 45.49142s |
| Declination | +20° 48′ 52.4079″ |
| Apparent magnitude (V) | 4.37 |
| Characteristics | |
| Spectral type | B2 IV or B2 V |
| B−V color index | −0.164±0.013 |
| Astrometry | |
| Radial velocity (Rv) | −14.9±0.6 km/s |
| Proper motion (μ) | RA: −1.92 mas/yr Dec.: −5.89 mas/yr |
| Parallax (π) | 3.56±0.19 mas |
| Distance | 920 ± 50 ly (280 ± 10 pc) |
| Absolute magnitude (MV) | −2.87 |
| Details | |
| Mass | 9.7±0.2 M☉ |
| Luminosity | 3,631.92 L☉ |
| Surface gravity (log g) | 3.54 cgs |
| Temperature | 22,420±1,440 K |
| Rotational velocity (v sin i) | 41 km/s |
| Age | 20.0±1.4 Myr |
| Other designations | |
| Ramus, 102 Her, BD+20°3674, FK5 3443, HD 166182, HIP 88886, HR 6787, SAO 85769, WDS J18088+2049 | |
| Database references | |
| SIMBAD | data |
102 Herculis, also named Ramus, is a single star in the northern constellation of Hercules. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.37. Based upon parallax measurements, it is located around 920 light years away from the Sun. The star is moving closer to the Earth with a heliocentric radial velocity of −15 km/s.
The stellar classification of this object matches a massive, early B-type star with a luminosity class of IV or V, corresponding to a subgiant or main sequence star, respectively. It is 20 million years old with nearly ten times the mass of the Sun and is spinning with a projected rotational velocity of 41 km/s. The strength of the stellar magnetic field has been measured at (209.5±135.4)×10−4 T. The star is radiating 3,632 times the Sun's luminosity from its photosphere at an effective temperature of 22,420 K.