NASA’s New Horizons spacecraft has sent back four low-resolution images of Kerberos, Pluto’s tiny moon.
This image of Kerberos completes the family portrait of Pluto’s moons. The image was created by combining four individual images taken by New Horizons’ LORRI instrument on July 14, 2015. Image credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute.
The images were acquired by New Horizons’ Long Range Reconnaissance Imager (LORRI) instrument on July 14 from a distance of 245,600 miles (396,100 km) and sent back to Earth on October 20.
Kerberos was discovered on June 28, 2011, by a team of astronomers led by Dr Mark Showalter of the SETI Institute using the NASA/ESA Hubble Space Telescope.
The moon was confirmed in subsequent Hubble images taken on July 3 and 18, 2011.
It was temporarily designated S/2011 (134340) 1 — and sometimes called P4. On 2 July 2013, the International Astronomical Union announced that it formally approved the name Kerberos for the moon (it is named after the three-headed dog of Greek mythology; all of Pluto’s moons are named for mythological figures associated with the underworld).
Kerberos orbits Pluto once every 32.1 days at a distance of 35,900 miles (57,800 km), and is located between the orbits of Nix and Hydra.
The moon appears to be smaller than the New Horizons team members expected and has a highly-reflective surface, counter to predictions prior to the Pluto flyby.
The new data show that the moon appears to have a double-lobed shape, about 7.4 miles (12 km) across in its long dimension and 2.8 miles (4.5 km) in its shortest dimension.
“Once again, the Pluto system has surprised us,” said Dr Hal Weaver from the Johns Hopkins University Applied Physics Laboratory, a project scientist for the New Horizons mission.
This composite image shows Charon and all four of Pluto’s small moons. All four small moons have highly elongated shapes, a characteristic thought to be typical of small bodies in the Kuiper Belt. Image credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute.
The New Horizons team speculates from its unusual shape that Kerberos could have been formed by the merger of two smaller objects.
The reflectivity of its surface is similar to that of Pluto’s other small moons and strongly suggests Kerberos, like the others, is coated with relatively clean water ice.
“The new results are expected to lead to a better understanding of Pluto’s fascinating satellite system,” the scientists said.
New Horizons is currently 3.16 billion miles (5.09 billion km) from Earth and 74.3 million miles (119.6 million km) beyond Pluto. It is healthy and all systems are operating normally.
