Delta Ceti
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 39m 28.95579s |
| Declination | +00° 19′ 42.6345″ |
| Apparent magnitude (V) | +4.06 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B2 IV |
| U−B color index | −0.88 |
| B−V color index | −0.21 |
| Variable type | β Cep |
| Astrometry | |
| Radial velocity (Rv) | 12.7±0.9 km/s |
| Proper motion (μ) | RA: 12.85±0.17 mas/yr Dec.: −2.94±0.11 mas/yr |
| Parallax (π) | 5.02±0.15 mas |
| Distance | 650 ± 20 ly (199 ± 6 pc) |
| Absolute magnitude (MV) | −2.41 |
| Orbit | |
| Period (P) | 169±6 yr |
| Semi-major axis (a) | 69–157 AU |
| Eccentricity (e) | 0.34±0.05 |
| Inclination (i) | 26–154° |
| Periastron epoch (T) | 2,444,054±781 HJD |
| Argument of periastron (ω) (primary) | 306±7° |
| Details | |
| δ Cet A | |
| Mass | 7.9 M☉ |
| Radius | 4.92±0.47 R☉ |
| Luminosity | 5,100+1,300 −1,000 L☉ |
| Surface gravity (log g) | 3.95±0.09 cgs |
| Temperature | 22,090±1,580 K |
| Metallicity [Fe/H] | −0.24 dex |
| Rotational velocity (v sin i) | 7±4 km/s |
| Age | 7−18 Myr |
| δ Cet B | |
| Mass | 1.1–2.5 M☉ |
| Luminosity | 2–51 L☉ |
| Other designations | |
| δ Cet, 82 Ceti, BD−00°406, FK5 91, HD 16582, HIP 12387, HR 779, SAO 110665 | |
| Database references | |
| SIMBAD | data |
Delta Ceti is a candidate binary star system in the equatorial constellation of Cetus. Its name is a Bayer designation that is Latinized from δ Ceti and abbreviated Delta Cet or δ Cet. The star's apparent visual magnitude of +4.06 means it is generally visible to the naked eye except in places highly affected to light pollution (see Bortle scale). It is 0.3238° north of the celestial equator compared to the celestial north pole's 90°. The star is positioned about 0.74° WNW of the spiral galaxy M77, but which at apparent magnitude 9.6 needs magnification to be made out and has an apparent size of only 0.1° by 0.12°.
Based upon an annual parallax shift of 5.02 mas as seen from Earth, it is around 650 light years from the Sun. Motion relative to our system's trajectory includes a highly parting vector: with a net radial velocity of about +13 km/s. It moves minutely across the celestial sphere – yet just over four times more in right ascension than in declination.