16 Delphini

16 Delphini is a star in the equatorial constellation 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]

16 Delphini

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Delphinus
Right ascension	20h 55m 38.5698s[1]
Declination	+12° 34′ 06.8774″[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]