Beta Ceti
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 43m 35.37090s |
| Declination | −17° 59′ 11.7827″ |
| Apparent magnitude (V) | 2.02 |
| Characteristics | |
| Evolutionary stage | Red clump |
| Spectral type | K0 III |
| U−B color index | +0.88 |
| B−V color index | +1.01 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | +12.9 km/s |
| Proper motion (μ) | RA: +232.55 mas/yr Dec.: +31.99 mas/yr |
| Parallax (π) | 33.86±0.16 mas |
| Distance | 96.3 ± 0.5 ly (29.5 ± 0.1 pc) |
| Absolute magnitude (MV) | −0.13 |
| Details | |
| Mass | 3.5 M☉ |
| Radius | 17.52±0.47 R☉ |
| Luminosity | 149.7±3.4 L☉ |
| Surface gravity (log g) | 2.43±0.07 cgs |
| Temperature | 4,792±35 K |
| Metallicity [Fe/H] | −0.09 dex |
| Rotational velocity (v sin i) | 18 km/s |
| Age | 460±130 Myr |
| Other designations | |
| Diphda, Deneb Kaitos, Difda al Thani, Rana Secunda, 16 Cet, BD−18°115, GCTP 134.00, Gj 31, HD 4128, HIP 3419, HR 188, SAO 147420 | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
Beta Ceti (β Ceti, abbreviated Beta Cet, β Cet), officially named Diphda /ˈdɪfdə/, is the brightest star in the constellation of Cetus. Although designated 'beta', it is actually brighter than the 'alpha' star in the constellation, Menkar, by half a magnitude. This orange giant is easy to identify due to its location in an otherwise dark section of the celestial sphere. Based on parallax measurements, it lies at an estimated distance of 96.3 light-years (29.5 parsecs) from the Sun.