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.