Finally, δ Cephei is usually considered to be a member of the loose association Cepheus OB6 (de Zeeuw et al. 1999; van Leeuwen et al. 2007; Majaess et al. 2012).
Cone (Wikipedia) A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
