Hubble Discovers Small Moon Orbiting the Dwarf Planet Makemake

Posted on April 26, 2016

Astronomers using the Hubble Space Telescope have discovered a small moon orbiting the dwarf planet Makemake. Makemake is 870 miles wide. It is the third largest known object past the orbit of Neptune. It is about two thirds the size of Pluto.

The moon is nicknamed MK 2 and has been provisionally designated S/2015 (136472) 1. It is located approximately 13,000 miles from the dwarf planet. It has a diameter that is about 100 miles across. The moon is 1,300 times fainter than Makemake.

Alex Parker of Southwest Research Institute, Boulder, Colorado, who led the image analysis for the observations, says in a statement, "Our preliminary estimates show that the moon's orbit seems to be edge-on, and that means that often when you look at the system you are going to miss the moon because it gets lost in the bright glare of Makemake."

The tiny moon is barely visible in the Hubble image above. You can find a hi-res version of the image here on the Hubble Site. The top image on this post is an artist's concept.

Astronomers may be able to use the moon to calculate the mass of Makemake. They will need more Hubble observations to make accurate measurements to determine if the moon's orbit is elliptical or circular.

The Hubble was also used to discover four of the five moons orbiting Pluto. Here is a video about the newly discovered moon MK 2:

SPACE