Delta Ceti

Delta Ceti
Location of δ Ceti (circled)
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
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
Distance650 ± 20 ly
(199 ± 6 pc)
Absolute magnitude (MV)−2.41
Details
Mass8.4±0.7 M
Radius4.6±0.8 R
Luminosity4,000 L
Surface gravity (log g)4.05±0.20 cgs
Temperature21,900±1,000 K
Metallicity [Fe/H]−0.24 dex
Rotational velocity (v sin i)7±4 km/s
Age7−18 Myr
Other designations
δ Cet, del Cet, 82 Ceti, BD−00°406, FK5 91, HD 16582, HIP 12387, HR 779, SAO 110665
Database references
SIMBADdata

Delta Ceti, Latinized from δ Ceti, is a single, blue-white hued star in the equatorial constellation of Cetus. The star's apparent visual magnitude of +4.06 means it is near to the cusp of the faintest third of the stars that are visible the ideally-placed naked eye. 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.

This is a Beta Cephei variable with a stellar classification of B2 IV. It varies in brightness with a period of 0.16114 days. Unlike most stars of its type, it does not display multiple periods of luminosity variation or multiple variations of its spectral line profiles. The star is about 7−18 million years and has a low projected rotational velocity of around 7 km/s, suggesting it is either rotating slowly or is being viewed from nearly pole on. It has 8.4 times the mass of the Sun and 4.6 times the Sun's radius. The star is radiating around 4,000 times the Sun's luminosity from its photosphere at an effective temperature of roughly 21,900 K