Discovery of tiny moon completes the set for worlds past Neptune 

Posted: March 12, 2017 by oldbrew in Astronomy, moon, solar system dynamics
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The largest ‘TNOs’

This is about the ‘no-name’ dwarf planet 2007 OR10, which has the unusual property of being 3 times further from the Sun at aphelion (furthest) than at perihelion (nearest).

Everybody gets a moon! With the discovery of a small moon orbiting the third-largest dwarf planet, all the large objects that orbit beyond Neptune now have satellites, reports New Scientist.

Trans-Neptunian objects (TNOs) spend most or all of their orbits beyond Neptune. Last April, the dwarf planet Makemake became the ninth of the ten TNOs with diameters near or above 1,000 kilometres known to have a moon.

So when dwarf planet 2007 OR10 was found to be rotating more slowly than expected, it was suspected that a moon might be the culprit.

To try to find it, John Stansberry at the Space Telescope Science Institute in Baltimore, Maryland, and his colleagues went back to the Hubble Space Telescope archives and found eight images of the world from 2009 and 2010.

“We basically just stretched the images a lot harder than the people who originally took the data, and there was a moon,” says Stansberry. The moon was in every image. The team presented these results at a planetary sciences meeting in October and now in a paper.

The discovery of moons around all the largest TNOs gives us a window, not just into the objects themselves, but also into our solar system’s history. TNOs are relics from the era of planet building, so they present an opportunity to peer into the past.

Full report: Discovery of tiny moon completes the set for worlds past Neptune | New Scientist

  1. oldbrew says:

    2007 OR10 is currently the largest known object in the Solar System without an official name. In 2011 Brown decided he finally had enough information to justify giving it one, because the discovery of water ice and the possibility of methane makes it noteworthy enough to warrant further study.[15] However, as of 2015, Brown had yet to propose a name, though he notes that in 2017 anyone will be able to make a proposal. – Wikipedia


  2. hunter says:

    It is incredible that what we all grew up with, a solar system of 9 planets, is so much more complex and diverse. I am glad Astronomers don’t believe “the science is settled” and are willing to have their assumptions and conclusions challenged.