Styx

Hubble Space Telescope discovery image of S/2012 (134340) 1 (encircled) with the outer moons' orbits shown. Compared to the other bodies, Pluto and Charon are shown greatly reduced in brightness.
Discovery
Discovered by	Showalter, M. R. and others [1]
Discovery date	June 26, 2012 [1] (verified 7 July 2012)
Detection method	Photographic [1]
Orbital characteristics
Mean orbit radius	42,000 km (26,000 mi) ± 2,000 km (1,200 mi)
Eccentricity	? 0
Orbital period	20.2 ± 0.1 days
Inclination	? 0
Satellite of	Pluto
Physical characteristics
Mean radius	5?12.5 km (3?8 mi)
Apparent magnitude	27 ± 0.3

Styx (formerly known as S/2012 (134340) 1 and informally as P5 ) is a small moon of the dwarf planet Pluto . ^{[1] [2]} It was discovered on June 26, 2012, using the Hubble Space Telescope . ^[1] It is the fifth moon of Pluto discovered so far. ^{[2] [3] [4]} The others are Charon , discovered in 1978, Nix and Hydra , which were discovered in 2005, and Kerberos , discovered in 2011.

Discovery [ change | change source ]

The moon was discovered using nine sets of images taken between 26 June and 9 July 2012 by Wide Field Camera 3 of the Hubble Space Telescope. ^[5] NASA announced the discovery on 11 July 2012. The images were taken as part of a Hubble survey searching for potential hazards for the New Horizons mission. ^{[1] [5]} The New Horizons space probe is going to Pluto at the moment and will arrive in July 2015. ^[5] The discovery of the moon has made scientists worried about the mission. Pluto may have more bodies, such as dust or rings , orbiting it which cannot be found. These bodies could damage the New Horizons probe. ^[3] The current plan for New Horizons is that it will pass just inside the orbit of Charon . But this could change if scientists think that the space probe will be damaged.

Physical properties [ change | change source ]

The moon is 10 to 25 km across. ^{[2] [3]} Because of its small size, it is likely to be irregular in shape. ^[2] The moon is very faint, about one one-hundred-thousandth as bright as Pluto. ^[4] The moon is likely to be made of water ice . ^[6]

Orbital properties [ change | change source ]

Styx orbits the centre of mass of Pluto and Charon at a distance of around 42,000 km. ^[7] This is in between the orbits of Charon and Nix . The orbital path of the moon is very nearly circular, like the other moons of Pluto. The moon orbits in the same orbital plane as the other moons. ^{[1] [3]} The moon takes around 20 days to orbit Pluto. ^[7]

Origin [ change | change source ]

The moon system around Pluto may exist because of a collision of Pluto with a large Kuiper belt body a very long time ago. ^{[1] [2] [4]} Pluto’s moons may have formed from the scattered pieces of rock left behind after the collision. ^[4]

References [ change | change source ]

1. ↑ ^{1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7} "S/2012 (134340) 1 (P5): Overview" . NASA. Archived from the original on 2015-07-05 . Retrieved 2012-09-02 .
2. ↑ ^{2.0 2.1 2.2 2.3 2.4} "Hubble discovers new Pluto moon" . BBC. 2012-07-11 . Retrieved 2012-07-28 .
3. ↑ ^{3.0 3.1 3.2 3.3} "Fifth moon is cold comfort for Pluto", New Scientist , no. 2874, Reed Business Information Ltd, p. 11, 2012-07-21
4. ↑ ^{4.0 4.1 4.2 4.3} "New Moon for Pluto: Hubble Telescope Spots a 5th Plutonian Satellite" . Scientific American. 2012-07-11 . Retrieved 2012-07-28 .
5. ↑ ^{5.0 5.1 5.2} "Hubble Discovers a Fifth Moon Orbiting Pluto" . NASA. 2012-07-11 . Retrieved 2012-07-28 .
6. ↑ "Astronomy Picture of the Day - 16 July 2012" . NASA . Retrieved 2012-07-28 .
7. ↑ ^{7.0 7.1} "Hubble Space Telescope detects fifth moon of Pluto (Update)" . Phys.Org. 2012-07-11 . Retrieved 2012-07-28 .