Charon (P1), discovered on magnified images of Pluto by James Christy in 1978, is a large satellite to Pluto. It is by observing torque Pluto - Charon occultation's scientists in 2005 were able to estimate the diameter of Charon is 1 207.2 ± 2.8 km (≈ 3 times smaller than our Moon). Charon has a mass about ten times less than Pluto and the diameter ratio is from 1 to 2. The infernal couple rotates around its center of gravity (barycenter), as two objects connected by a central bar rigid, like a dumbbell. Charon is located only 19 000 km and the dwarf planet moves around the planet with a period of 6.4 days, equal to the rotation period of Pluto, which is a geostationary orbit. It seems that Charon is primarily an object of ice water with very few rocks (70% of rocks to Pluto). Charon may be the result of a collision with icy Pluto coat (unconfirmed hypothesis).
NixIn Greek mythology, Nyx was the goddess of the night and the mother of Charon, the man who carried in his boat souls across the river Styx to the underworld ruled by Pluto. The IAU has changed its name to "Nix" by spelling Egyptian goddess name to avoid confusion with two asteroids that are already named "Nyx". and HydraHydra is the mythological serpent with nine heads who guarded the kingdom of Pluto that is the Roman name for the Greek god of the underworld, Hades. In addition to the relationship with Pluto, the names were chosen because of their initial "N" and "H" which are also the first letters of New Horizons, the NASA probe launched in January 2006 to the Pluto system. are two small satellites discovered orbiting Pluto, thanks to the Hubble Space Telescope in May and June 2005 by two American astronomers Alan Stern and Hal Weaver. The two new moons orbiting P2 and P3 to 48,708 km and 64,749 km of Pluto, much farther than Charon. They are between 45 and 160 km in diameter and 5 000 times less luminous than Charon. The two satellites traveling in the plane of Charon. They were cataloged under the provisional reference S/2005 P1 and S/2005 P2, before becoming Hydra and Nix in 2006. Since then, the Hubble Space Telescope discovered a fourth moon orbiting in 32.1 days around Pluto, she was named kerberos (P4). The natural satellite was discovered on Hubble images taken June 28, 2011 and confirmed on 3 and 18 July 2011.
It is preparing the overview by the New Horizons mission in 2015, this discovery was made. Pluto is a distant objective for space exploration. Over its very low mass partly, the limited data available on this mysterious object. The New Horizons spacecraft, launched on 19 January 2006, will be the first spacecraft to visit Pluto. New Horizons received a gravity assist from Jupiter, its speed of 19 km/s, is the fastest of all the probes ever launched by humans.
It comes closer to the dwarf planet in the summer of 2015, after traveling 6.4 billion miles. Observations will begin approximately five months before the nearest way and should continue for about a month later.
The spacecraft onboard instruments imaging spectrometry and other measuring devices to determine the geological and morphological characteristics of Pluto and its moon Charon, but also map the components of their surface and study the atmosphere Pluto.
|| || |
Image: Pluto system, with three visible satellites.
Image taken by Hubble on May 15, 2005. Since June 2011, another natural satellite was discovered by Hubble. The fourth satellite of Pluto called Kerberos P4, it is not visible in the 2005 image above. The tiny moon P4 orbits Pluto in 32.1 days. In 2012, the development of adaptive optics makes it possible to observe these objects from ground-based telescopes.