Delta Ceti

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 $12.7$ north of the celestial equator compared to the celestial north pole's $12.85$. The star is positioned about $−2.94$ 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 $8.4$ by $4.05$.

Based upon an annual parallax shift of $7$ as seen from Earth, it is around $4.6$ from the Sun. Motion relative to our system's trajectory includes a highly parting vector: with a net radial velocity of about $21,900$. 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 $0.324 °$, 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 $90 °$

Name
This star, along with α Cet (Menkar), λ Cet (Menkar), γ Cet (Kaffaljidhma), μ Cet, ξ1 Cet and ξ2 Cet were Al Kaff al Jidhmah, "the Part of a Hand".

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Kaff al Jidhmah were the title for five stars :γ Cet as Kaffaljidhma, ξ1 Cet as Al Kaff al Jidhmah I, ξ2 Cet as Al Kaff al Jidhmah II, δ Cet as Al Kaff al Jidhmah III and μ Cet as Al Kaff al Jidhmah IV (exclude α Cet and λ Cet.)

In Chinese, 天囷 (Tiān Qūn), meaning Circular Celestial Granary, refers to an asterism consisting of δ Ceti, α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for δ Ceti itself is 天囷九 (Tiān Qūn jiǔ, the Ninth Star of Circular Celestial Granary.)