Moon Around the Trans-Neptunian object 2007 OR10

These two images, taken a year apart, reveal a moon orbiting the trans-Neptunian object 2007 OR₁₀. Each image, taken by the NASA/ESA Hubble Space Telescope's Wide Field Camera 3, shows the companion in a different orbital position around its parent body.

2007 OR₁₀ is the third-largest known trans-Neptunian object, behind Pluto and Eris, and the largest unnamed world in the Solar System. The pair is located in the Kuiper Belt, a realm of icy debris left over from the formation of the Solar System.

The trans-Neptunian object is about 1520 kilometres across; the moon is estimated to be 240 kilometres to 400 kilometres in diameter. 2007 OR₁₀, like Pluto, follows an eccentric orbit, but it is currently three times farther than Pluto is from the Sun.

Links:

• NASA Press Release
• Hubble Images of 2007 OR₁₀