This star in Cetus takes its name from the Arabic for 'tail', a common element in the names of stars across the sky, though more usually spelt Deneb. Most famously, Deneb in Cygnus represents the tail of the Swan, whereas Dheneb in Cetus represents the tail, or part of the tail, of the Whale or sea monster. Dheneb is also known as Deneb Algenubi, the 'southern tail', to distinguish it from Deneb Kaitos Shemali, the 'northern tail of the whale', which lies westward and a little northward from Dheneb. A third star, formally known as Diphda, also carries the name Deneb Kaitos, the 'tail of the whale'.
Together, these three tail stars of Cetus form a near equilateral triangle, with Dheneb lying at the northeastern corner. While all three stars are clearly visible to the naked eye (Dheneb itself shines with an apparent magnitude of +3.46), none of them are particularly bright, and the shape of the Whale's tail can be difficult to distinguish in the night sky.
Dheneb is an evolved orangestar some 124 light years from the Solar System. The star has burned through its hydrogen fuel and is now consuming helium in its core, a process that has caused it to expand to some fifteen times the Sun'sdiameter. Giantstars like this are, however, much less dense than main sequence stars, and despite its size, the mass of Dheneb is only a little greater than that of the Sun. Dheneb is a metal-rich star, noted for showing unusually hight levels of cyanogen and iron in its make-up.