| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 21h22m 05.199s[1] |
| Declination | 19° 48′ 16.24″[1] |
| Apparent magnitude (V) | 4.09[2] |
| Characteristics | |
| Spectral type | K1III[3] |
| U−B color index | +1.05[2] |
| B−V color index | +1.11[2] |
| Astrometry | |
| Radial velocity (Rv) | −10.80[4] km/s |
| Proper motion (μ) | RA: +105.35[1] mas/yr Dec.: +63.51[1] mas/yr |
| Parallax (π) | 20.93 ± 0.17 mas[1] |
| Distance | 156 ± 1 ly (47.8 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.68[5] |
| Details | |
| 1 Peg A | |
| Mass | 1.57[6] M☉ |
| Radius | 12[6] R☉ |
| Luminosity | 71.78[5] L☉ |
| Surface gravity (log g) | 2.59[7] cgs |
| Temperature | 4,600[8] K |
| Metallicity [Fe/H] | +0.01[7] dex |
| Rotational velocity (v sin i) | 1.2[9] km/s |
| Other designations | |
1 Peg, BD+19°4691, FK5 804, GC 29914, HD 203504, HIP 105502, HR 8173, SAO 107073, CCDM J21221+1949A, WDS J21221+1948A[10] | |
| Database references | |
| SIMBAD | data |
1 Pegasi (1 Peg) is a triple star[11] system in the constellation Pegasus, located approximately 156 light years away from the Sun based on parallax.[1] It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.09.[2] The system is moving closer to the Earth with a heliocentric radial velocity of −11 km/s.[4]
The primary component is a giant with a stellar classification of K1III,[3] a star that has exhausted the hydrogen supply at its core and evolved away from the main sequence. It has 1.57[6] times the mass of the Sun and has expanded to 12[6] times the Sun's radius. The star is radiating 72[5] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,600 K.[8]
There are several companions in addition to the primary. The brightest, component B, is a magnitude 9.3, K-type main-sequence star with a class of K0 V orbiting at an angular separation of 36.6" from the primary; it is itself a single-lined spectroscopic binary with an orbital period of 3.042 ± 0.011 years and eccentricityof0.290±0.022.[12] Visual companions C, with magnitude 12.9 and separation 64.7", and D, with magnitude 9.6 and separation 5.3", have been reported.[13]
|
| |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| |||||||||||||
| Stars |
| ||||||||||||
| |||||||||||||
| Star clusters |
| ||||||||||||
| Nebulae |
| ||||||||||||
| Galaxies |
| ||||||||||||
| |||||||||||||
| |||||||||||||
