New Pluto Moon Found—”Fringe Benefit” of Search for Risky Rings

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Only a year after Hubble Space Telescope scientists discovered Pluto’s still unnamed fourth moon, they’ve found a fifth.


Finding the new moon this summer was a “fringe benefit” of a monthlong program to scan Pluto for rocky rings that could endanger NASA’s New Horizons spacecraft, said planetary astronomer Mark Showalter, who’s leading the Hubble scanning project. The probe is to fly by the dwarf planet in July 2015.

Even in the Hubble’s best images, the new moon—some 3.7 billion miles (5.9 billion) miles from the sun—is visible only as a speck of light.

Based on its brightness, the temporarily named P5 is probably 6 to 15 miles (10 to 25 kilometers) in diameter—about two-thirds the size of P4, the Plutonian moon discovered in 2011.

The new moon adds one more level to the complexity of the Pluto system, which was already surprisingly complex for a world that’s only two-thirds the width of Earth’s moon, the team says.

Pluto’s “Russian Doll” Moons

At about 29,000 miles (47,000 kilometers) from Pluto, the new moon orbits in a 1:3 resonance with the dwarf planet’s largest moon, Charon—meaning the newfound natural satellite takes precisely three times longer than Charon to circle Pluto.

Written By: Richard A. Lovett
continue to source article at news.nationalgeographic.com

11 COMMENTS

  1. This far out, the Sun’s (and other planets’) gravity is so weak, that small clusters of rocky¹ bodies can form stable (dwarf) planet/moon systems which would be torn apart closer in.  There are probably similar groups of orbiting bodies in the Oort Cloud and Kuiper Belt. – http://en.wikipedia.org/wiki/O

    ¹  Water is a rock at these temperatures.

  2. I must be a little behind in my news. Is Pluto considered to be a planet? dwarf planet? big ice ball? What’s going on with Pluto’s status.

    GPWC, It would be a far stretch if something related to Pluto is found in the Quran. Ancient astrology from the Babylonians did not know of the outer planets so they were not figured into charts. Yet back peddling is fun to watch.

  3. I hope they reach 45 moons…….I can’t wait to see a moon called P45. Kind of appropriate for a sacked planet.

    ( for anyone not from the UK….P45 is the form you get when made redundant )

  4.  
    At about 29,000 miles (47,000 kilometers) from Pluto, the new moon
    orbits in a 1:3 resonance with the dwarf planet’s largest moon,
    Charon—meaning the newfound natural satellite takes about three times
    longer than Charon to circle Pluto.

    Intriguingly, all of the other moons also lie in orbital resonances with Charon. Nix, discovered in 2005, lies in the 1:4 resonance. P4 lies in the 1:5 resonance. And Hydra, also discovered in 2005, is in the 1:6 resonance.

    This suggests that the moons have been in orbit long enough to have gravitational interactions  settle them into stable orbits with resonant orbital periods. – Just like the moons of many other planets.

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