| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 24m 06.88433s[1] |
| Declination | −04° 50′ 13.2692″[1] |
| Apparent magnitude (V) | 5.78 (6.45 + 6.63)[2] |
| Characteristics | |
| Spectral type | A0 V[3] + A0[2] |
| U−Bcolor index | –0.11[4] |
| B−Vcolor index | –0.04[4] |
| Astrometry | |
| Radial velocity (Rv) | +6[5] km/s |
| Proper motion (μ) | RA: +26.90[1]mas/yr Dec.: −7.35[1]mas/yr |
| Parallax (π) | 8.04±0.63 mas[1] |
| Distance | 410 ± 30 ly (124 ± 10 pc) |
| Orbit[6] | |
| Period (P) | 145.07±1.85 yr |
| Semi-major axis (a) | 0.402±0.003″ |
| Eccentricity (e) | 0.702±0.003 |
| Inclination (i) | 161.4±0.7° |
| Longitude of the node (Ω) | 113.5±3.0° |
| Periastronepoch (T) | 1987.66±0.05 |
| Argument of periastron (ω) (secondary) | 296.9±3.0° |
| Details | |
| 51 Aqr A | |
| Mass | 2.80±0.10[7] M☉ |
| Luminosity | 88.2+14.8 −14.2[7] L☉ |
| Temperature | 10,328±71[7] K |
| Rotational velocity (v sin i) | 91[7] km/s |
| Other designations | |
| 51 Aqr,BD−05°5780,HD 212404,HIP 110578,HR 8533,SAO 146067,WDS J22241-0450[8] | |
| Database references | |
| SIMBAD | data |
51 Aquarii is abinary star[2] system located around 410[1] light years away from the Sun in theequatorialconstellation ofAquarius.51 Aquarii is itsFlamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with a combinedapparent visual magnitude of 5.78.[4] The system is moving further from the Earth with a heliocentricradial velocity of +6 km/s.[5]
The dual nature of this system was discovered byS. W. Burnham in 1873with a 6 inches (15 cm)Alvan Clarkrefractor.[9] The pair orbit each other with aperiod of 145 years and a largeeccentricity of 0.7.[6] The magnitude 6.45[2] primary, designated component A, is anA-type main sequence star with astellar classification of A0 V.[3] It has a high rate of rotation with aprojected rotational velocity of 91 km/s.[10] The secondary component has a matching class of A0 with a visual magnitude of 6.63.[2] It has an effective temperature of 10,238 K.
