HD 156846
HD 156846 is a binary star system in the equatorial constellation of Ophiuchus, positioned a degree SSE of Messier 9. It has a yellow hue and is just barely bright enough to be visible to the naked eye with an apparent visual magnitude of 6.5. The system is located at a distance of 156 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −68.5 km/s, and is predicted to come to within 85.0 light-years in about 476,000 years.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 17h 20m 34.31093s |
| Declination | −19° 20′ 01.4944″ |
| Apparent magnitude (V) | 6.506 + 14.10 |
| Characteristics | |
| Spectral type | G1V + M4V |
| B−V color index | 0.557 |
| Astrometry | |
| Radial velocity (Rv) | −68.50±0.22 km/s |
| Proper motion (μ) | RA: −137.102±0.097 mas/yr Dec.: −143.204±0.074 mas/yr |
| Parallax (π) | 20.9210 ± 0.0508 mas |
| Distance | 155.9 ± 0.4 ly (47.8 ± 0.1 pc) |
| Absolute magnitude (MV) | 3.055 |
| Details | |
| A | |
| Mass | 1.35±0.045 M☉ |
| Radius | 2.12±0.12 R☉ |
| Luminosity | 5.07 L☉ |
| Surface gravity (log g) | 3.92±0.08 cgs |
| Temperature | 5,969±44 K |
| Metallicity [Fe/H] | +0.17±0.04 dex |
| Rotational velocity (v sin i) | 5.05±0.50 km/s |
| Age | 2.8+0.1 −0.2 Gyr |
| B | |
| Mass | 0.59 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary, component A, is a G-type star with a stellar classification of G1V. The absolute visual magnitude of this star is 1.13 magnitudes above the main sequence, indicating it has evolved slightly off the main sequence. It has 1.35 times the mass of the Sun and 2.12 times the Sun's radius. The star is an estimated 2.8 billion years old and is spinning with a projected rotational velocity of 5 km/s. It is radiating five times the luminosity of the Sun from its photosphere at an effective temperature of 5,969 K.
The magnitude 14.4 secondary companion, component B, was discovered by the American astronomer R. G. Aitken in 1910. It lies at an angular separation of 5.1″ from the primary, corresponding to a projected separation of 250 AU. This is a red dwarf with a class of M4V and has an estimated 59% of the Sun's mass.