pluto system S/2012 P 1

S/2012 (134340) 1 (also informally known as S/2012 P 1 or P5) is a small natural satellite of Pluto whose existence was announced on 11 July 2012. It is the fifth confirmed satellite of Pluto, and was found approximately one year after S/2011 (134340) 1, Pluto's fourth discovered satellite.

Discovery

The satellite was discovered using nine sets of images taken between 26 June and 9 July 2012 by the Wide Field Camera 3 fitted to the Hubble Space Telescope.^[2] The survey work leading to the moon's discovery was in preparation for the arrival of the New Horizons space probe, currently en route to the Pluto system.
The discovery of another small moon in the area of Pluto has heightened concerns that this region of space may harbor more bodies too small to be detected, raising fears that the probe may be damaged by an uncharted body or ring as it passes through the system.^[3]

Physical properties

The moon is estimated to have a diameter of between 10 and 25 kilometers (6 and 16 mi).^[4][5] These figures are inferred from the apparent magnitude of the moon and by using an estimated albedo of 0.35 and 0.04 for the lower and upper bounds, respectively.^[1]

Orbital properties

S/2012 P 1's orbital period is estimated to be 20.2 ± 0.1 days,^[1] putting it about 5.4% from a 1:3 resonance with the Charon–Pluto orbital period. With Pluto's other moons Nix, S/2011 P 1 and Hydra, it forms part of a 1:3:4:5:6 sequence of near resonances.

Origin

The unexpectedly complex moon system around Pluto may be the result of a collision between Pluto and another Kuiper belt object in the distant past.^[6] Pluto's moons may have coalesced from the debris from such an event, similar to the giant impact believed to have created the Earth's Moon. The orbital resonances may have acted as "ruts" to gather material from the smashup.^[7]

See also

• Moons of Pluto