Kerberos (moon)

Mark R. Showalter et al.

Kerberos, provisional designation S/2011 ( 134340 ) 1, unofficially referred to as P4 and sometimes wrongly called S/2011 P 1, is one of five known moons of the dwarf planet Pluto, the existence of which was announced on 20 July 2011. Its diameter is estimated at 14 to 40 km.

Discovery and designation

On July 20, 2011, NASA announced the discovery of a fourth moon Pluto. The temporarily named S/2011 ( 134340 ) 1 designated Trabant was discovered using the Hubble Space Telescope in the search for any existing planetary rings. The discovery, a team of astronomers led by Mark R. Showalter. With an estimated size of 13 and 34 km it was at the time of its discovery, the smallest known moon of Pluto. The moon had been discovered on a recorded on 28 June 2011 with the Hubble Wide Field Camera 3 Photo and could be confirmed on further recordings of 3 and 18 July. The exposure time for these shots was eight minutes. At archived Hubble images of Pluto system taken on February 15, 2006 with the ACS / HRC instrument, the moon could also be identified. In most previous recordings but the heavenly bodies was not visible because they were taken with a shorter exposure time.

S/2011 ( 134340 ) 1 was initially the provisional designation, which was awarded by the International Astronomical Union (IAU ). NASA called it in their discovery message with the unofficial project name P4. On 2 July 2013, the IAU announced that the moon was officially recognized as the fourth moon of Pluto and confirmed the submitted based on an Internet poll suggested name by Mark Showalter, Kerberos, after the Hellhound in Greek mythology that guards the entrance to the underworld.

Web properties

The average distance to Pluto is 59000 ± 2000 km, so that the orbit between the already known moons Nix and Hydra is. Previously measured movement data indicate a nearly circular equatorial orbit. For a more precise determination of the orbital data, further observations are necessary.

Physical Properties

The Moon has a visual magnitude of only ten percent of the moon Nix. With an assumed geometric albedo of 0.35 to 0.04, the diameter of the object 14-40 km.

Due to the small size of Kerberos will have an irregular shape, similar to other small moons of this size.

Research

So far, the moon appears only on some shots from the Hubble Space Telescope, which the moon could be detected. Details are, however, so that the surface can not be seen. The space probe New Horizons will fly by in July 2015 near and study Pluto and its moons in detail.

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