EE Pegasi
Star in the constellation Pegasus
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EE Pegasi is a variable triple star system in the northern constellation Pegasus. It is too faint to be readily visible to the naked eye with a combined apparent visual magnitude of 6.96.[3] The system is located at a distance of approximately 472 light years from the Sun based on Parallax,[2] but is drifting closer with a radial velocity of −23 km/s.[5]
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 21h 40m 01.87850s[2] |
| Declination | +09° 11′ 05.1169″[2] |
| Apparent magnitude (V) | 6.96[3] (7.09 + 9.40)[4] |
| Characteristics | |
| A | |
| Spectral type | A3m[4] |
| B−V color index | 0.120±0.018[3] |
| B | |
| Spectral type | F5V[4] |
| B−V color index | 0.44±0.05[4] |
| Astrometry | |
| Radial velocity (Rv) | −22.6[5] km/s |
| Proper motion (μ) | RA: +41.237[2] mas/yr Dec.: +13.723[2] mas/yr |
| Parallax (π) | 6.9143±0.0658 mas[2] |
| Distance | 472 ± 4 ly (145 ± 1 pc) |
| Absolute magnitude (MV) | 0.50[3] |
| Orbit[4] | |
| Primary | AB |
| Name | C |
| Period (P) | 2,628 d |
| Eccentricity (e) | 0.52±0.11 |
| Inclination (i) | 88.6[5]° |
| Periastron epoch (T) | 2,443,120±24 JD |
| Argument of periastron (ω) (secondary) | −85±11° |
| Semi-amplitude (K1) (primary) | 4.4±0.6 km/s |
| Details[4] | |
| A | |
| Mass | 2.15±0.02 M☉ |
| Radius | 2.09±0.03 R☉ |
| Luminosity | 53.42[3] L☉ |
| Surface gravity (log g) | 4.13±0.01 cgs |
| Rotational velocity (v sin i) | 40.0±1.0[6] km/s |
| Age | 300 Myr |
| B | |
| Mass | 1.33±0.01 M☉ |
| Radius | 1.31±0.01 R☉ |
| Surface gravity (log g) | 4.33±0.01 cgs |
| Rotational velocity (v sin i) | 26.0±2.0[6] km/s |
| Other designations | |
| EE Peg, BD+08°4714, HD 206155, HIP 106981, SAO 126971[7] | |
| Database references | |
| SIMBAD | data |
This system was found to be an eclipsing binary by German astronomer Cuno Hoffmeister in 1935, and has since been the subject of multiple studies. The pair orbit each other closely with a period of 2.628 days.[1][8] The magnitude 7.09 primary, component A, is an Am star with a stellar classification of A3m. It has more than double the mass and radius of the Sun. The secondary companion, component B, is an F-type main-sequence star with a class of F5V and a visual magnitude of 9.40. A third component is a smaller orange or red dwarf that orbits the main pair every 4.01 years.[4]