HD 178911
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h 09m 04.35193s |
| Declination | +34° 36′ 01.2420″ |
| Apparent magnitude (V) | 6.70 (6.89 + 8.96 + 7.88) |
| Characteristics | |
| HD 178911 Aa/Ab | |
| Evolutionary stage | Main sequence |
| Spectral type | G1V + K1V |
| B−V color index | 0.643±0.007 |
| HD 178911 B | |
| Spectral type | G5V |
| B−V color index | 0.750±0.015
... |
| Astrometry | |
| HD 178911 Aa/Ab | |
| Radial velocity (Rv) | −38.09±1.01 km/s |
| Proper motion (μ) | RA: 76.618 mas/yr Dec.: 207.126 mas/yr |
| Parallax (π) | 20.2306±0.3846 mas |
| Distance | 161 ± 3 ly (49.4 ± 0.9 pc) |
| Absolute magnitude (MV) | 3.28 |
| HD 178911 B | |
| Radial velocity (Rv) | −40.324±0.0012 km/s |
| Proper motion (μ) | RA: 57.177 mas/yr Dec.: 195.900 mas/yr |
| Parallax (π) | 24.3775 ± 0.0274 mas |
| Distance | 133.8 ± 0.2 ly (41.02 ± 0.05 pc) |
| Absolute magnitude (MV) | 4.90 |
| Orbit | |
| Primary | HD 178911 Aa |
| Companion | HD 178911 Ab |
| Period (P) | 1,296.984±0.355 d yr |
| Semi-major axis (a) | 0.074±0.002″ |
| Eccentricity (e) | 0.597±0.003 |
| Inclination (i) | 147.29±0.99° |
| Longitude of the node (Ω) | 276.91±1.45° |
| Argument of periastron (ω) (secondary) | 83.88±0.87° |
| Semi-amplitude (K1) (primary) | 6.47±0.09 km/s |
| Semi-amplitude (K2) (secondary) | 8.33±0.18 km/s |
| Details | |
| HD 178911 Aa | |
| Mass | 0.802±0.055 M☉ 1.234±0.027 M☉ |
| HD 178911 Ab | |
| Mass | 0.622±0.053 M☉ 0.942±0.021 M☉ |
| HD 178911 B | |
| Mass | 1.03±0.02 M☉ |
| Radius | 1.05±0.02 R☉ |
| Luminosity | 1.00±0.02 L☉ |
| Surface gravity (log g) | 4.40±0.02 cgs |
| Temperature | 5,642±29 K |
| Metallicity [Fe/H] | 0.23 |
| Rotational velocity (v sin i) | 4.6 |
| Age | 4.8±1.3 Gyr |
| Other designations | |
| STF2747, HD 178911, HR 7272, WDS 19091+3436 | |
| HD 178911 A: BD+34 3439, HIP 94076, SAO 67879, PPM 82386, LTT 15608, NLTT 47474 | |
| HD 178911 B: BD+34 3438, HIP 94075, SAO 67875, PPM 82385, LTT 15608, NLTT 47473 | |
| Database references | |
| SIMBAD | data |
HD 178911 is a triple star system with an exoplanetary companion in the northern constellation of Lyra. With a combined apparent visual magnitude of 6.70, it is a challenge to view with the naked eye. The system is located at a distance of approximately 161 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −38 km/s.