Delta Equulei
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 14m 28.81531s |
| Declination | +10° 00′ 25.1259″ |
| Apparent magnitude (V) | 5.19 + 5.52 |
| Characteristics | |
| Spectral type | F7V + F7V |
| U−B color index | −0.03 |
| B−V color index | +0.49 |
| Astrometry | |
| Radial velocity (Rv) | −16.2±0.3 km/s |
| Proper motion (μ) | RA: +42.39 mas/yr Dec.: −304.19 mas/yr |
| Parallax (π) | 54.89±0.50 mas |
| Distance | 59.4 ± 0.5 ly (18.2 ± 0.2 pc) |
| Absolute magnitude (MV) | +3.14 |
| Orbit | |
| Period (P) | 2,084.03±0.10 d |
| Semi-major axis (a) | 231.9650±0.0080 mas |
| Eccentricity (e) | 0.436851±0.000025 |
| Inclination (i) | 99.4083±0.0098° |
| Longitude of the node (Ω) | 23.362±0.012° |
| Periastron epoch (T) | 53112.071±0.052 MHJD |
| Argument of periastron (ω) (secondary) | 7.735±0.013° |
| Details | |
| δ Equ A | |
| Mass | 1.192±0.012 M☉ |
| Radius | 1.30±0.08 R☉ |
| Luminosity | 2.25 L☉ |
| Temperature | 6,200±150 K |
| Metallicity [Fe/H] | −0.07±0.09 dex |
| Age | 3.0 Gyr |
| δ Equ B | |
| Mass | 1.187±0.012 M☉ |
| Radius | 1.25±0.08 R☉ |
| Luminosity | 2.07 L☉ |
| Temperature | 6,200±150 K |
| Other designations | |
| δ Equ, 7 Equulei, BD+09°4746, GJ 822.0, HD 202275, HIP 104858, HR 8123, LTT 16227, SAO 126643 | |
| Database references | |
| SIMBAD | data |
Delta Equulei, Latinized from δ Equulei, is the second brightest star in the constellation Equuleus. Delta Equulei is a binary star system about 60 light years away, with components of class G0 and F5. 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. The luminosity of the larger star is calculated to be 2.23 solar, and the smaller to be 2.17.