Nix (moon)

Nix is a non-spherical moon of Pluto. It was found along with Hydra in June 2005 by the Hubble Space Telescope Pluto Companion Search Team.

The discovery images were taken on May 15, 2005 and May 18, 2005; the moons were independently found by Max J. Mutchler on June 15, 2005 and Andrew J. Steffl on August 15, 2005. The discoveries were announced on October 31, 2005, after confirmation from photographs archived in 2002. The moon were designated S/2005 P 1 (Hydra) and S/2005 P 2 (Nix).IAU Circular No. 8625 describing the discovery

The moon follows a circular orbit in the same plane as Charon. It takes 24.9 days to circle around Pluto.

Before its size was directly measured, the moon was calculated to have a diameter of between 46 km, if its reflectivity is similar to Charon's 35%, and 137 km, if it had a reflectivity of 4%, like the darkest Kuiper belt objects.  Nix is slightly fainter than Hydra, suggesting that it is somewhat smaller in size.  In the discovery image, Nix is 6,300 times fainter than Pluto.Brightness Difference on 2005-05-15: (5th root of 100) ^ (Nix APmag 23.38 - Pluto APmag 13.87) = 6,368x

Early research appeared to show that Nix was reddish like Pluto and unlike the other moons,(Final preprint)  a, i, e per JPL (site updated 2008 Aug 25) but more recent reports have been that it is grey like the remaining moons. (Final preprint)

Nix was visited along with Pluto by the New Horizons mission in 2015.

The formal name "Nix", from the Greek goddess of darkness and night, and mother of Charon, was announced on June 21, 2006 on IAU Circular 8723,IAU Circular No. 8723 naming the moons where the designation Pluto II is also given. Together with Hydra, Pluto's third moon, the initials are those of the New Horizons probe. The initial proposal was to use the Classical spelling Nyx, but to avoid confusion with the asteroid 3908 Nyx, this was changed to "the Egyptian spelling of the Greek name".

 References 

 Other websites 
 Nix Profile  by NASA's Solar System exploration
 Background information regarding our two newly discovered satellites of Pluto  – The discoverers' website
 NASA's Hubble reveals possible new moons around Pluto – Hubble press release
 Two more moons discovered orbiting Pluto (SPACE.com)
 Pluto's newest moons named Hydra and Nix (SPACE.com)
 [(Final preprint)

Category:Pluto's moons