spaceSpace and Physics

New Horizons Reveals The Mystery Of Kerberos

guest author image

Amy Lynn

Guest Author

3143 New Horizons Reveals The Mystery Of Kerberos
Image of Kerberos taken by LORRI on July 14, just 7 hours after New Horizons’ closest approach to Pluto. NASA/JHUAPL/SwRI

NASA just released the images we’ve all been waiting for – our first look at Pluto’s fifth moon Kerberos. New Horizons passed within 396,100 kilometers (245,600 miles) of Kerberos, capturing images of Pluto’s tiny moon just seven hours before its closest approach. The newly released image is a combination of four separate images captured by the spacecraft’s LOng Range Reconnaissance Imager (LORRI) and was deconvoluted to reduce pixelation and reveal Kerberos in unprecedented detail. 

So far, Pluto has been full of surprises, and the new pictures prove that Pluto has many more tricks up its sleeve. Kerberos may look like nothing more than a pixelated blob, but researchers can tell a lot from these images. Due to Kerberos’ diminutive size – a mere 12 kilometers (7.4 miles) by 4.5 kilometers (2.8 miles) – we are not going to get as detailed images as we see with Nix, but we can expect exciting science data. 


Prior to the Pluto encounter, scientists used Hubble images to “weigh” the tiny moon and measured its gravitational influence on its neighboring moons. The science team determined the force was surprisingly strong with Kerberos, as the moon had a strong influence over its neighbors, indicating it was relatively large and massive. The moon appeared very faint in Hubble images, suggesting it had a dark charcoal-like surface. However, the new images tell a very different story. “Once again, the Pluto system has surprised us,” New Horizons project scientist Hal Weaver, from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, said in a press release

Downlinked on October 20, the new images show Kerberos to be smaller than expected with a dual-lobed shape much like we see in Hydra and in Comet 67P/Churyumov-Gerasimenko, currently orbited by ESA’s Rosetta spacecraft. The small lobe measures approximately 5 kilometers (3 miles) across, with the larger lobe spanning 8 kilometers (5 miles). Judging by its shape, the science team speculates that Kerberos formed by two smaller objects merging together. 

Based on new data, Kerberos appears to be smaller than expected and has a highly reflective surface. Kerberos reflects approximately 50 percent of the light that hits it, indicating its surface is coated with relatively clean water ice, just like the other small moons. Since the predictions for Nix, Hydra, and Styx were pretty accurate, scientists are baffled by Kerberos and how different it appears to be. “Our predictions were nearly spot-on for the other small moons, but not for Kerberos,” said New Horizons co-investigator Mark Showalter of the SETI Institute in Mountain View, California. 

New Horizons principal investigator Alan Stern told IFLScience, “We didn’t expect Kerberos to have two lobes and such a reflective surface. The previous HST results didn’t show any indications and predicted that Kerberos would have a darker surface. All in all the four small satellites fit in as much brighter than Charon, and were likely to have originated from the giant impact that formed Charon.”


With the new data and images collected by New Horizons, the team hopes to have a better understanding of Pluto’s family of moons. 


spaceSpace and Physics
  • tag
  • pluto,

  • images,

  • New Horizons,

  • kerberos