70 Pegasi
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 23h 29m 09.29698s |
| Declination | +12° 45′ 37.9918″ |
| Apparent magnitude (V) | 4.56 |
| Characteristics | |
| Spectral type | G8 IIIa |
| B−V color index | 0.940 |
| Astrometry | |
| Radial velocity (Rv) | −16.88±0.43 km/s |
| Proper motion (μ) | RA: +61.40 mas/yr Dec.: +24.82 mas/yr |
| Parallax (π) | 18.65±0.78 mas |
| Distance | 175 ± 7 ly (54 ± 2 pc) |
| Absolute magnitude (MV) | 0.90 |
| Orbit | |
| Period (P) | 941.03±0.12 d |
| Eccentricity (e) | 0.713±0.006 |
| Argument of periastron (ω) (secondary) | 57.0±1.2° |
| Semi-amplitude (K1) (primary) | 3.16±0.04 km/s |
| Details | |
| 70 Peg A | |
| Mass | 2.49±0.06 M☉ |
| Radius | 8.95±0.69 R☉ |
| Luminosity | 49.2±2.4 L☉ |
| Surface gravity (log g) | 2.92±0.05 cgs |
| Temperature | 5,108±185 K |
| Metallicity [Fe/H] | 0.05±0.03 dex |
| Rotational velocity (v sin i) | 3.6 km/s |
| Age | 590±40 Myr |
| Other designations | |
| 70 Peg, BD+11° 5009, FK5 885, HD 221115, HIP 115919, HR 8923, SAO 108638 | |
| Database references | |
| SIMBAD | data |
70 Pegasi is a binary star system in the northern constellation Pegasus. It is a faint star, visible to the naked eye under good seeing conditions, with an apparent visual magnitude of 4.56. The measured annual parallax shift measured from Earth's orbit is 18.65 mas, yielding a distance estimate of around 175 light years. The visual magnitude of the star is diminished by an extinction of 0.07±0.02 due to interstellar dust. It is moving closer to the Sun with a radial velocity of −17 km/s.
This is a single-lined spectroscopic binary with an orbital period of 2.58 years (941 days) and a high eccentricity of 0.713. The visible component has a stellar classification of G8 IIIa, indicating it is an evolved G-type giant star. It is a probable red clump star, which would mean it is generating energy through helium fusion at its core. The star has 2.5 times the mass of the Sun and has expanded to nine times the Sun's radius. It is radiating about 49 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,108 K.
The secondary is most likely a low mass main sequence star with no more than 0.4 times the mass of the Sun.