Zeta Delphini
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 35m 18.53621s |
| Declination | +14° 40′ 27.1739″ |
| Apparent magnitude (V) | +4.647 |
| Characteristics | |
| Spectral type | A3Va / L5 |
| U−B color index | +0.14 |
| B−V color index | +0.105 |
| Astrometry | |
| Radial velocity (Rv) | −27.68±0.37 km/s |
| Proper motion (μ) | RA: 45.504 mas/yr Dec.: 11.510 mas/yr |
| Parallax (π) | 14.9441±0.1284 mas |
| Distance | 218 ± 2 ly (66.9 ± 0.6 pc) |
| Absolute bolometric magnitude (Mbol) | 0.523 / 14.59 |
| Details | |
| ζ Del A | |
| Mass | 2.5 ± 0.2 M☉ |
| Luminosity | 48.63 ± 1.66 L☉ |
| Surface gravity (log g) | 3.60±0.12 cgs |
| Temperature | 8236±124 K |
| Metallicity [Fe/H] | −0.05 dex |
| Rotational velocity (v sin i) | 108.0±3.6 km/s |
| Age | 525 ± 125 Myr |
| ζ Del B | |
| Mass | 55 ± 10 MJup |
| Luminosity | 0.00012 ± 0.00001 L☉ |
| Surface gravity (log g) | 5.0+0.5 −1.0 cgs |
| Temperature | 1550+250 −100 K |
| Age | 525 ± 125 Myr |
| Other designations | |
| ζ Del, 4 Del, BD+14°4353, HD 196180, HIP 101589, HR 7871, SAO 106274 | |
| Database references | |
| SIMBAD | ζ Del |
| ζ Del B | |
Zeta Delphini (ζ Delphini) is a star in the constellation of Delphinus. With an apparent magnitude of about 4.6, it is faintly visible to the naked eye. Parallax measurements of the system made by the Gaia spacecraft put it at a distance of about 218 light-years (67 parsecs).
Zeta Delphini has a spectral type of A3V, implying it is an A-type main-sequence star. These types of stars are bluish-white colored, and have effective temperatures between 7100 and 11500 K: Zeta Delphini has a temperature of 8336 K. Its age is estimated to be around 500 million years, considerably younger than the Sun.
In 2014, the discovery of a brown dwarf around Zeta Delphini was announced. Zeta Delphini B is a brown dwarf with a spectral type of L5 (but may be from L3 to L7), and has a mass of about 55 Jupiters. At over 13 arcseconds away, this brown dwarf is separated at least 910 AU from Zeta Delphini.
A 2021 study identified Zeta Delphini as a Lambda Boötis star, a type of star with peculiar chemical abundances. It is the first known Lambda Boötis star orbited by a brown dwarf.