EQ Pegasi
EQ Pegasi is a nearby binary system of two red dwarfs. Both components are flare stars, with spectral types of M4Ve and M6Ve respectively, and a current separation between the components of 5.8 arcseconds. The system is at a distance of 20.4 light-years, and is 950 million years old.[10]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus |
| EQ Pegasi A | |
| Right ascension | 23h 31m 52.1743s[1] |
| Declination | +19° 56′ 14.1284″[1] |
| Apparent magnitude (V) | 10.38 (min)[2] |
| EQ Pegasi B | |
| Right ascension | 23h 31m 52.5741s[3] |
| Declination | +19° 56′ 14.0041″[3] |
| Apparent magnitude (V) | 12.58 (min)[2] |
| Characteristics | |
| A | |
| Evolutionary stage | red dwarf |
| Spectral type | M4Ve[2] |
| Variable type | Flare star[2] |
| B | |
| Evolutionary stage | red dwarf |
| Spectral type | M6Ve[2] |
| Variable type | Flare star[2] |
| Astrometry | |
| EQ Pegasi A | |
| Proper motion (μ) | RA: 577.605±0.133[1] mas/yr Dec.: −59.640±0.096[1] mas/yr |
| Parallax (π) | 159.7098 ± 0.0827[1] mas |
| Distance | 20.42 ± 0.01 ly (6.261 ± 0.003 pc) |
| EQ Pegasi B | |
| Proper motion (μ) | RA: 553.472±0.193[3] mas/yr Dec.: 20.338±0.142[3] mas/yr |
| Parallax (π) | 160.0598 ± 0.1079[3] mas |
| Distance | 20.38 ± 0.01 ly (6.248 ± 0.004 pc) |
| Orbit[4] | |
| Period (P) | 359 yr |
| Semi-major axis (a) | 6.87″ |
| Eccentricity (e) | 0.20 |
| Inclination (i) | 123.5° |
| Details | |
| A | |
| Mass | 0.36[5] M☉ |
| Luminosity | 0.019[6] L☉ |
| Temperature | 3,585[1] K |
| B | |
| Mass | 0.19[5] M☉ |
| Luminosity | 0.008[6] L☉ |
| Temperature | 3,309[3] K |
| Other designations | |
| EQ Peg A: TYC 1723-23-1, 2MASS J23315208+1956142[8] | |
| EQ Peg B: LFT 1800, LHS 3966, LTT 16920, NLTT 57136, TYC 1723-23-2, 2MASS J23315244+1956138[9] | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
Discovery
EQ Pegasi was first noticed to be a binary star by Carl A. Wirtanen who in the course of a systematic survey of the McCormick Observatory photographic plates for M-type dwarfs, detected a companion about two magnitudes fainter at a separation of 3.5 arcseconds.[11]
Both components are also though to be single-lined spectroscopic binaries, with faint companions that have not been resolved in orbits of a few years.[5]
In culture
In 1998, it was the basis of a hoax, as a telecommunications company claimed it had discovered "alien" signals originating from the star.[12]
References
- 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.
- Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
- 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.
- Heintz, W. D. (1984). "Orbits of 16 visual binaries". The Astronomical Journal. 89: 1063. Bibcode:1984AJ.....89.1063H. doi:10.1086/113602.
- Tokovinin, A. "Multiple Star Catalog". Retrieved 2019-08-12.
- Morales, J. C.; Ribas, I.; Jordi, C. (2008). "The effect of activity on stellar temperatures and radii". Astronomy and Astrophysics. 478 (2): 507. arXiv:0711.3523. Bibcode:2008A&A...478..507M. doi:10.1051/0004-6361:20078324.
- "BD+19 5116". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 August 2017.
- "BD+19 5116A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 August 2017.
- "BD+19 5116A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 August 2017.
- Crosley, M. K.; Osten, R. A. (2018). "Constraining Stellar Coronal Mass Ejections through Multi-wavelength Analysis of the Active M Dwarf EQ Peg". The Astrophysical Journal. 856 (1). 39. arXiv:1802.03440. Bibcode:2018ApJ...856...39C. doi:10.3847/1538-4357/aaaec2.
- Wirtanen, C. A. (1941). "A New dMe Double Star". Publications of the Astronomical Society of the Pacific. 53 (316): 340. Bibcode:1941PASP...53..340W. doi:10.1086/125371.
- "BBC News | Sci/Tech | Alien hoax dismays scientists". news.bbc.co.uk. Retrieved 2018-09-25.
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