On 12th May, 2015, in News Center of the “New Horizons” Mission we could read in “NASA’s New Horizons Spots Pluto’s Faintest Known Moons” the following message:
“Kerberos and Styx were discovered in 2011 and 2012, respectively, by New Horizons team members using the Hubble Space Telescope. Styx, circling Pluto every 20 days between the orbits of Charon and Nix, is likely just 4 to 13 miles (approximately 7 to 21 kilometers) in diameter, and Kerberos, orbiting between Nix and Hydra with a 32-day period, is just 6 to 20 miles (approximately 10 to 30 kilometers) in diameter. Each is 20 to 30 times fainter than Nix and Hydra.”
The NASA's message explained further:
“The images detecting Kerberos and Styx shown here were taken with New Horizons' most sensitive camera, the Long Range Reconnaissance Imager (LORRI), from April 25-May 1. Each observation consists of five 10-second exposures that have been added together to make the image in the left panel, and extensively processed to reduce the bright glare of Pluto and Charon and largely remove the dense field of background stars (center and right panels), in order to reveal the faint satellites, whose positions and orbits, along with those of the brighter moons Nix and Hydra, are given in the right panel.”
As we see, the main effort of the “New Horizons”-Team was to clarify the background of the picture (“to remove the dense field of background stars”) in order to leave the Pluto and his moons alone. However, as I am sure, there are many additional objects just behind the “Pluto-Family”, I suppose, some of the “removed” objects cannot be “background stars”, but the debris of the Andrea star, the members of the damaged star “cloud”. On the original video we can also see some together moving groups of objects, which could be interpreted as another Pluto-like system; compare the two groups encircled in the picture below with the above video.
It will be very interesting to see the newest pictures of the stellar background of the “Pluto-Family”.