Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Pegasus |
Right ascension | 23h 43m 59.48560s[1] |
Declination | 29° 21′ 41.2342″[1] |
Apparent magnitude (V) | 4.93[2] (5.07 / 8.10)[3] |
Characteristics | |
Spectral type | K0III[4] |
U−B color index | +0.63[5] |
B−V color index | +0.96[5] |
Astrometry | |
Radial velocity (Rv) | −8.33[6] km/s |
Proper motion (μ) | RA: +71.10[1] mas/yr Dec.: -40.58[1] mas/yr |
Parallax (π) | 14.54 ± 0.56 mas[1] |
Distance | 224 ± 9 ly (69 ± 3 pc) |
Absolute magnitude (MV) | 0.75[2] |
Orbit[3] | |
Period (P) | 630.15 yr |
Semi-major axis (a) | 1.614″ |
Eccentricity (e) | 0.112 |
Inclination (i) | 60.64° |
Longitude of the node (Ω) | 172.55° |
Periastron epoch (T) | B 2247.71 |
Argument of periastron (ω) (secondary) | 241.27° |
Details | |
78 Peg A | |
Mass | 1.50[7] M☉ |
Radius | 10[7] R☉ |
Luminosity | 57.35[2] L☉ |
Surface gravity (log g) | 2.62[7] cgs |
Temperature | 4,898[7] K |
Metallicity [Fe/H] | +0.01[2] dex |
Rotational velocity (v sin i) | 1.1[8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
78 Pegasi is a binary star system in the northern constellation of Pegasus. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.93.[2] The system is located approximately 224 light years from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −8 km/s.[6] The double-star nature of this system was discovered by A. G. Clark in 1862. The components of this system orbit each other over a 630-year period with an eccentricity of 0.11.[10]
The primary member, designated component A, is a magnitude 5.07[3] giant star with a stellar classification of K0III,[4] having exhausted the supply of hydrogen at its core and expanded to 10[7] times the Sun's radius. It is a red clump giant,[11] which indicates it is on the horizontal branch and is generating energy through core helium fusion. It has 1.5[7] times the mass of the Sun and is radiating 57[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,898 K.[7] The secondary companion, component B, is magnitude 8.10.[3]