51 Pegasi

51 Pegasi / Helvetios
51 Pegasi is located in 100x100
51 Pegasi

51 Peg (circled) in the constellation Pegasus.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pegasus
Right ascension 22h 57m 27.9805s[1]
Declination +20° 46′ 07.797″[1]
Apparent magnitude (V) 5.49[2]
Characteristics
Spectral type G2V+[3]
Apparent magnitude (B) 6.16[4]
Apparent magnitude (R) 5.0[4]
Apparent magnitude (I) 4.7[4]
Apparent magnitude (J) 4.66[4]
Apparent magnitude (H) 4.23[4]
Apparent magnitude (K) 3.91[2]
U−B color index +0.20[5]
B−V color index +0.67[5]
Astrometry
Radial velocity (Rv)−33.33[1] km/s
Proper motion (μ) RA: +207.328[1] mas/yr
Dec.: +61.164[1] mas/yr
Parallax (π)64.4048 ± 0.0543 mas[1]
Distance50.64 ± 0.04 ly
(15.53 ± 0.01 pc)
Absolute magnitude (MV)4.48[6]
Details[7]
Mass1.09±0.02 M☉
Radius1.152±0.009 R☉
Luminosity1.398±0.016 L☉
Surface gravity (log g)4.33[8] cgs
Temperature5,768±8[6] K
Metallicity = 0.18±0.07
Metallicity [Fe/H]+0.20[8] dex
Rotation21.9±0.4 days[9]
Rotational velocity (v sin i)5.6[10] km/s
Age4.8+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[11]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata

51 Pegasi (abbreviated 51 Peg), formally named Helvetios /hɛlˈviːʃiəs/,[12] 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.[13]

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