Pluto’s two newly discovered moons
Astronomers using NASA’s Hubble Space Telescope have confirmed two new moons around the planet Pluto. The moons were first discovered with Hubble’s Advanced Camera for Surveys in May 2005, but on Feb. 15, 2006 they took a look for additional satellites and characterized the orbits of the moons. These further observations rule out the possibility of other satellites of roughly similar size orbiting Pluto inside the orbits of the two moons. The moons, provisionally named S/2005 P 1 and S/2005 P 2, are approximately 40,000 and 30,000 miles away from Pluto. In the pic, Pluto is in the center and Charon is just below it. P 1 is to the right and just below Charon. P 2 is to the right of Pluto and Charon. The satellites fall under the category of plutinos, trans-Neptunian objects with a 2:3 orbital resonance with Neptune that form the inner part of the Kuiper belt. Plutinos are usually named after underworld deities, like Pluto’s moon Charon, the ferryman who took the recently deceased across the river Acheron (not Styx) provided they had an coin (obolus) to pay for their ride (which was customarily placed under the tongue of the dead). Neither of the moons, nor the ninth planet for that matter, have yet been officially named, a process that requires the approval of the International Astronomical Union (IAU).
NASA, ESA, H. Weaver (Johns Hopkins University/Applied Physics Laboratory), A. Stern (Southwest Research Institute) and the HST Pluto Companion Search Team