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 J2000.0 | |
|---|---|
| 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 |
| Companion | 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 | |
| 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]
References
edit- ^ a b Ebbighausen, E. G. (June 1971). "The photometric elements of the eclipsing binary EE Pegasi". The Astronomical Journal. 76: 460–464. Bibcode:1971AJ.....76..460E. doi:10.1086/111143. Retrieved 11 February 2022.
- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644
- ^ a b c d e f g Lacy, Claud H.; Popper, Daniel M. (1984). "Absolute dimensions and masses of eclipsing binaries. IV - EE Pegasi is a triple star". Astrophysical Journal. 281 (1): 268–75. Bibcode:1984ApJ...281..268L. doi:10.1086/162096.
- ^ a b c Linnell, A. P.; et al. (March 1996), "EE Pegasi Revisited: A Spectrum Synthesis and New Light Synthesis Study", Astrophysical Journal, 459: 721, Bibcode:1996ApJ...459..721L, doi:10.1086/176937
- ^ a b Torres, G.; et al. (February 2010). "Accurate masses and radii of normal stars: modern results and applications". The Astronomy and Astrophysics Review. 18 (1–2): 67–126. arXiv:0908.2624. Bibcode:2010A&ARv..18...67T. doi:10.1007/s00159-009-0025-1. S2CID 14006009.
- ^ "EE Peg". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-11-21.
- ^ "EE Peg". The International Variable Star Index. AAVSO. Retrieved 11 February 2022.