Ilmarë, or Varda I, full designation 174567 Varda I Ilmarë, is the single known natural satellite of the Kuiper Belt planetoid 174567 Varda. It was discovered by Keith Noll et al. in 2009, at a separation of about 0.12 arcsec, using discovery images taken by the Hubble Space Telescope on 26 April 2009, and reported in 2011. At approximately 326 km in diameter (about 45% that of its primary), it is the fourth or fifth-largest known moon of a trans-Neptunian object, after Pluto I Charon, Eris I Dysnomia, Orcus I Vanth and very possibly Haumea I Hiʻiaka. Assuming that Ilmarë has the same albedo and density as Varda, Ilmarë would constitute approximately 8.4% of the system's mass, approximately 2.2×1019 kg. |