The new Pluto Moon with the unofficial abbreviation P5 in the circle of his siblings. © NASA / ESA / A. Feild (STScI)
He has a diameter between ten and 25 kilometers, circles between the satellites Charon and Nix and has received the provisional name S / 2012 (134340) 1: A new moon increases the number of known satellites of the dwarf planet Pluto to five. An international team of astronomers had directed the Hubble Space Telescope 14 times on Pluto between June 26 and July 9, detecting a new, weak point of light between the four known moons. The former ninth planet Pluto, which the International Astronomical Union demoted to a dwarf planet in 2006, has a diameter of only 2, 300 kilometers. But he now has a stately crowd of moons: Already in 1978, the largest Trabant Charon was discovered, whose diameter is at 1, 200 kilometers. In 2005, observations from the Hubble telescope brought two more moons to light: Nix and Hydra, whose diameters so far can only be estimated - it's between 40 and 160 kilometers. Another, even smaller moon was also in July 2011 on Hubble recordings. He has no official name yet, but unofficially referred to as P4.

The new family member (nickname: P5) circles in the same plane as the other moons and has a track radius of 42, 000 kilometers. He moves between Charon, the innermost moon, and Nix. "The discovery of so many small moons indirectly tells us that the Pluto system lurks large amounts of invisible, small particles, " says Harold Weaver of Johns Hopkins University in the State of Maryland. Probably moons and debris originated ages ago in a major collision. Since collisions in the outer reaches of the solar system usually take place at relatively slow speeds, many debris could still orbit around today.

That means trouble for the NASA mission "New Horizons", which is on the way to Pluto since 2006. The probe will reach the system in summer 2015 and race past the dwarf planet at a speed of 14.3 kilometers per second. "The Pluto system inventory helps us find a safe lane for the New Horizons spacecraft, " says Alan Stern of the Southwest Research Institute in Boulder, Colorado, the scientific director of the mission. According to current plans, New Horizons is scheduled to make its closest approach of approximately 9, 000 kilometers within the Charon Railway.

After the short visit, where planetary scientists will have the first opportunity to observe Pluto up close, New Horizons will travel on to another object in the so-called Kuiper Belt. In this area beyond the orbit of the planet Neptune circle numerous similar ice worlds like Pluto, which probably changed hardly since the origin of the solar system. display

Communication from the Space Telescope Science Institute © science.de - Ute Kehse

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