HD 202908
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Equuleus |
| A | |
| Right ascension | 21h 18m 34.85s |
| Declination | +11° 34′ 08.2″ |
| Apparent magnitude (V) | 7.25±0.03 |
| B | |
| Right ascension | 21h 18m 34.80s |
| Declination | +11° 34′ 08.0″ |
| Apparent magnitude (V) | 8.87±0.14 |
| Characteristics | |
| Spectral type | G0 V (combined) |
| U−B color index | +0.07 |
| B−V color index | +0.56 |
| Aa | |
| Spectral type | F9 V or G1 V |
| Ab | |
| Spectral type | G0 V or G2 V |
| B | |
| Spectral type | G1.5 V or G6 V |
| Astrometry | |
| Radial velocity (Rv) | 6.24±0.04 km/s |
| Proper motion (μ) | RA: +29.213 mas/yr Dec.: −49.564 mas/yr |
| Parallax (π) | 19.3447±0.0543 mas |
| Distance | 168.6 ± 0.5 ly (51.7 ± 0.1 pc) |
| A | |
| Absolute magnitude (MV) | +3.73±0.13 |
| B | |
| Absolute magnitude (MV) | +5.35±0.19 |
| Orbit | |
| Primary | A |
| Companion | B |
| Period (P) | 28,685±173 d |
| Semi-major axis (a) | 0.5177±0.0046″ |
| Eccentricity (e) | 0.8651±0.0008 |
| Inclination (i) | 100.36±0.16° |
| Longitude of the node (Ω) | 255.03±0.17° |
| Periastron epoch (T) | 24,468,123±3 JD |
| Argument of periastron (ω) (secondary) | 171.9±0.3° |
| Semi-amplitude (K1) (primary) | 6.13±0.07 km/s |
| Semi-amplitude (K2) (secondary) | 13.95±0.09 km/s |
| Orbit | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | 3.9660465±0.0000015 d |
| Eccentricity (e) | 0.0033±0.0008 |
| Argument of periastron (ω) (secondary) | 271±13° |
| Semi-amplitude (K1) (primary) | 66.03±0.06 km/s |
| Semi-amplitude (K2) (secondary) | 69.69±0.06 km/s |
| Details | |
| The System | |
| Metallicity [Fe/H] | −0.04 dex |
| Age | 6.4±0.7 Gyr |
| The A Subystem | |
| Temperature | 6,100±150 K |
| Rotational velocity (v sin i) | 10 km/s |
| Aa | |
| Mass | 1.14 M☉ |
| Radius | 1.06±0.08 R☉ |
| Luminosity | 1.41+0.15 −0.14 L☉ |
| Ab | |
| Mass | 1.08 M☉ |
| Radius | 0.97±0.08 R☉ |
| Luminosity | 1.16+0.13 −0.11 L☉ |
| B | |
| Mass | 0.97 M☉ |
| Radius | 0.91±0.08 R☉ |
| Luminosity | 0.84+0.09 −0.08 L☉ |
| Temperature | 5,703±1,090 K |
| Rotational velocity (v sin i) | 9 km/s |
| Other designations | |
| AG+11°2644, BD+10°4514, GC 29812, HD 202908, HIP 105200, SAO 107015, ADS 14839AB, CCDM J21186+1134AB, WDS J21186+1134AB | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
HD 202908, also known as HIP 105200, is a triple star located in the equatorial constellation Equuleus. It has an apparent magnitude of 7.01, making it readily visible in binoculars but not to the naked eye. When resolved, the components have apparent magnitudes of 7.25 and 8.87 respectively. The system is located relatively close at a distance of 169 light years based on Gaia DR3 parallax measurements and it is receding with a heliocentric radial velocity of 6.24 km/s.