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, β Cet, 16 Cet, BD−18 115, GJ 31, HD 4128, HIP 3419, HR 188, SAO 147420, PLX 134.00 | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
Beta Ceti is the brightest star in the constellation of Cetus. It is officially named Diphda, pronounced /ˈdɪfdə/; Beta Ceti is its Bayer designation, which is Latinized from β Ceti and abbreviated Beta Cet and β Cet. 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.