Beta Delphini
Binary star in the constellation of Delphinus / From Wikipedia, the free encyclopedia
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Beta Delphini (β Delphini, abbreviated Beta Del, β Del) is a binary star in the constellation of Delphinus. It is the brightest star in Delphinus.
Quick Facts Constellation, Right ascension ...
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Delphinus |
Right ascension | 20h 37m 32.94130s[1] |
Declination | +14° 35′ 42.3195″[1] |
Apparent magnitude (V) | 3.617±0.016[2] (4.11 + 5.01)[3] |
Characteristics | |
Spectral type | F5 III + F5 IV[4] |
B−V color index | A: 0.43±0.14 B: 0.56±0.25[1] |
Astrometry | |
Beta Delphini A | |
Proper motion (μ) | RA: +118.09[1] mas/yr Dec.: -48.06[1] mas/yr |
Parallax (π) | 32.33 ± 0.47 mas[1] |
Distance | 101 ± 1 ly (30.9 ± 0.4 pc) |
Absolute magnitude (MV) | 1.58±0.12[2] |
Beta Delphini B | |
Absolute magnitude (MV) | 2.79±0.14[2] |
Orbit[3] | |
Period (P) | 26.660 yr |
Semi-major axis (a) | 0.440″ |
Eccentricity (e) | 0.36 |
Inclination (i) | 61° |
Longitude of the node (Ω) | 177° |
Periastron epoch (T) | 1989.50 yr |
Argument of periastron (ω) (secondary) | 349° |
Semi-amplitude (K1) (primary) | 7.6[5] km/s |
Details | |
Beta Delphini A | |
Mass | 1.75±0.002[2] M☉ |
Luminosity | 24[6] L☉ |
Surface gravity (log g) | 3.50[6] cgs |
Temperature | 6587[6] K |
Metallicity [Fe/H] | –0.05[2] dex |
Rotational velocity (v sin i) | 49.8[6] km/s |
Age | 1.79+0.17 −0.72[2] Gyr |
Beta Delphini B | |
Mass | 1.47±0.04[2] M☉ |
Luminosity | 8[7] L☉ |
Other designations | |
Database references | |
SIMBAD | data |
Close
The two components of the system are designated Beta Delphini A (officially named Rotanev /ˈroʊtənɛv/, which is historically the name of the system)[11][12] and B.