Delta Equulei
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| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 14m 28.815s[1] |
| Declination | +10° 00′ 25.13″[1] |
| Apparent magnitude (V) | 4.49 / 5.4 |
| Characteristics | |
| Spectral type | F5V+ / G0 |
| U−B color index | −0.01 |
| B−V color index | 0.5 |
| Variable type | None |
| Astrometry | |
| Radial velocity (Rv) | −15.4 km/s |
| Proper motion (μ) | RA: 42.39 ± 0.68[1] mas/yr Dec.: -304.19 ± 0.42[1] mas/yr |
| Parallax (π) | 54.39 ± 0.15[2] mas |
| Distance | 60.0 ± 0.2 ly (18.39 ± 0.05 pc) |
| Absolute magnitude (MV) | 4.99 |
| Details | |
| Mass | 1.22 / 1.17 M☉ |
| Radius | 1.19 / 0.525 R☉ |
| Luminosity | 2.23 / 2.17 L☉ |
| Age | 1.6 – 2.8 billion years |
| Orbit | |
| Companion | Delta Equulei B |
| Period (P) | 5.7 yr |
| Semi-major axis (a) | 0.26" |
| Eccentricity (e) | 0.42 |
| Inclination (i) | 100° |
| Longitude of the node (Ω) | 23° |
| Periastron epoch (T) | 1912.77 |
| Other designations | |
| Database references | |
| SIMBAD | data |
Delta Equulei is the second brightest star in the constellation Equuleus. Delta Equulei is a binary star system about 60 light years away,[2] with components of class G0 and F5.[3] Their combined magnitude is 4.47, and their absolute magnitude is 3.142. There is controversy as to the exact masses of the stars. One study puts the larger at 1.22 solar masses and the smaller at 1.17, while another pegs them at 1.66 and 1.593.[3] The luminosity of the larger star is calculated to be 2.23 solar, and the smaller to be 2.17.[3]
References
- ↑ 1.0 1.1 1.2 1.3 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
- ↑ 2.0 2.1 Muterspaugh, Matthew W. et al. (2005). "PHASES High-Precision Differential Astrometry of δ Equulei". The Astronomical Journal 130 (6): 2866–2875. arXiv:astro-ph/0507585. Bibcode:2005AJ....130.2866M. doi:10.1086/497035.
- ↑ 3.0 3.1 3.2 "Delta Equulei". University of Illinois Astronomy department.
External links
- "HD 202275 -- Star". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 2007-01-22.
- Delta Equulei
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