65489 Ceto

65489 Ceto ( /ˈsiːtoʊ/) is a binary trans-Neptunian object (TNO) discovered on March 22, 2003 by C. A. Trujillo and M. Brown at Palomar. It is named after the sea goddess Ceto from Greek mythology. The object was identified as a binary on April 11, 2006 by K. Noll, H. Levison, W. Grundy and D. Stephens using the Hubble Space Telescope; the companion object is named Phorcys (/ˈfɔərsɨs/, formally (65849) Ceto I Phorcys), after the Greek sea god. The Ceto system is considered the second known binary centaur, using an extended definition of a centaur as an object on an non-resonant (unstable) orbit with the perihelion inside the orbit of Neptune. It came to perihelion in 1989.