any known large TNO; William Grundy and colleagues proposed that this low density would imply that Salacia never collapsed into a solid body, in which case it would not be in hydrostatic equilibrium. Salacia's infrared spectrum is almost featureless, indicating an abundance of water ice of less than 5% on the surface. Its light-curve amplitude is only 3%. Satellite Salacia has one natural satellite, Actaea, that orbits its primary every at a distance of and with an eccentricity of . It was discovered on 21 July 2006 by Keith Noll, Harold Levison, Denise Stephens and William Grundy with the Hubble Space Telescope. Actaea is magnitudes fainter than Salacia, implying a diameter ratio of 2.98 for equal albedos. Hence, assuming equal albedos, it has a diameter of According to the estimate from 2017 based on an improved modelling the size of Actaea is slightly larger being . Actaea has the same color as Salacia (V−I = and , respectively), supporting the assumption of equal albedos. It has been calculated that the Salacia system should have undergone enough tidal evolution to circularize their orbits, which is consistent with the low measured eccentricity, but that the primary need not have been tidally locked. The ratio of its semi-major axis to its primary's Hill radius is 0.0023, the tightest trans-Neptunian binary with a known orbit. Salacia and Actaea will next occult each other in 2067. Name This minor planet was named after Salacia (), the goddess of salt water and the wife of Neptune. Naming citation was published on 18 February 2011 (). The moon's name, Actaea , was assigned on the same date. Actaea is a nereid or sea nymph. Planetary symbols are no longer much used in astronomy, so Salacia never received a symbol in the astronomical literature. There is no standard symbol for Salacia used by astrologers either. Denis Moskowitz, a software engineer in Massachusetts who designed the symbols for most of the dwarf planets, proposed a stylised hippocamp () as the symbol for Salacia, befitting Salacia as Neptune's consort. See also List of Solar System objects by size Notes References External links (120347) Salacia at Johnston's Archive Salacia: As big as Ceres, but much farther away (Emily Lakdawalla – 2012/06/26) 120347 120347 Discoveries by Michael E. Brown Named minor planets Binary trans-Neptunian objects 20040922