16 Delphini
Star in the constellation Delphinus
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16 Delphini is a star in the northern constellation of Delphinus. It has an apparent magnitude of 5.54,[2] making it faintly visible to the naked eye. The star is relatively close at a distance of 198 light years[1] but is receding with a poorly constrained radial velocity of 2 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 55m 38.5698s[1] |
| Declination | +12° 34′ 06.877″[1] |
| Apparent magnitude (V) | 5.54±0.01[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A5 V[4] |
| U−B color index | +0.09[2] |
| B−V color index | +0.11[2] |
| Astrometry | |
| Radial velocity (Rv) | 2.0±4.3[5] km/s |
| Proper motion (μ) | RA: +39.558 mas/yr[1] Dec.: +27.772 mas/yr[1] |
| Parallax (π) | 16.4866±0.06 mas[1] |
| Distance | 197.8 ± 0.7 ly (60.7 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.63[6] |
| Details | |
| Mass | 2.0±0.1[7] M☉ |
| Radius | 1.9±0.1[8] R☉ |
| Luminosity | 18.7[6] L☉ |
| Surface gravity (log g) | 4.10±0.14[7] cgs |
| Temperature | 9,093±309[7] K |
| Metallicity [Fe/H] | −0.01[9] dex |
| Rotational velocity (v sin i) | 159[10] km/s |
| Age | 400+150 −215[7] Myr |
| Other designations | |
| 16 Del, AG+12°2414, BD+12°4501, GC 29202, HD 199254, HIP 103298, HR 8012, SAO 106666, WDS J20556+1234A | |
| Database references | |
| SIMBAD | data |
16 Delphini is a chemically peculiar A-type main-sequence star with a stellar classification of A5 V. It has twice the Sun's mass,[7] 1.9 times its radius,[8] and shines at 18.7 L☉.[6] This yields an effective temperature of 9,039 K,[7] giving it a white glow. 16 Del is 400 million years old[7] – 56.5% through its main sequence lifetime[3] – and spins rapidly with a projected rotational velocity of 159 km/s.[10]
16 Del has a companion that was first discovered by John Herschel and was even noted to be a spectroscopic binary.[11] It is now considered to be a single star. [12]