51 Pegasi
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 22h 57m 27.9805s |
| Declination | +20° 46′ 07.797″ |
| Apparent magnitude (V) | 5.49 |
| Characteristics | |
| Spectral type | G2V+ |
| Apparent magnitude (B) | 6.16 |
| Apparent magnitude (R) | 5.0 |
| Apparent magnitude (I) | 4.7 |
| Apparent magnitude (J) | 4.66 |
| Apparent magnitude (H) | 4.23 |
| Apparent magnitude (K) | 3.91 |
| U−B color index | +0.20 |
| B−V color index | +0.67 |
| Astrometry | |
| Radial velocity (Rv) | −33.33 km/s |
| Proper motion (μ) | RA: +207.328 mas/yr Dec.: +61.164 mas/yr |
| Parallax (π) | 64.4048±0.0543 mas |
| Distance | 50.64 ± 0.04 ly (15.53 ± 0.01 pc) |
| Absolute magnitude (MV) | 4.48 |
| Details | |
| Mass | 1.09±0.02 M☉ |
| Radius | 1.152±0.009 R☉ |
| Luminosity | 1.398±0.016 L☉ |
| Surface gravity (log g) | 4.33±0.02 cgs |
| Temperature | 5,768±8 K |
| Metallicity | = 0.18±0.07 |
| Metallicity [Fe/H] | +0.18±0.01 dex |
| Rotation | 21.9±0.4 days |
| Rotational velocity (v sin i) | 2.54(62) km/s |
| Age | 4.8+0.7 −0.4 Gyr |
| Other designations | |
| Helvetios, 51 Peg, GJ 882, HR 8729, BD+19°5036, HD 217014, LTT 16750, GCTP 5568.00, SAO 90896, HIP 113357 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
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51 Pegasi (abbreviated 51 Peg), formally named Helvetios /hɛlˈviːʃiəs/, is a Sun-like star located 50.6 light-years (15.5 parsecs) from Earth in the constellation of Pegasus. It was the first main-sequence star found to have an exoplanet (designated 51 Pegasi b, officially named Dimidium) orbiting it.