Moon Around the Dwarf Planet 2007 OR10

These two images, taken a year apart, reveal a moon orbiting the dwarf planet 2007 OR 10 . Each image, taken by the Hubble Space Telescope's Wide Field Camera 3, shows the companion in a different orbital position around its parent body.

2007 OR 10 is the third-largest known dwarf planet, 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 solar system's formation.

The dwarf planet is about 950 miles across; the moon is estimated to be 150 miles to 250 miles in diameter. 2007 OR 10 , like Pluto, follows an eccentric orbit, but it is currently three times farther than Pluto is from the sun.

About the colours

These images were taken with HST's WFC3/UVIS instrument using the F606W (477.3 nm) filter. Color was added to the grayscale images using a blue color mapping.

About the data

HST data from proposals 11644 , M. Brown (Caltech) and 12234 , W. Fraser (Herzberg Institute of Astrophysics) were used in the analysis.