These images are from a Hubble Space Telescope survey to find Kuiper Belt objects (KBOs) in support of NASA's New Horizons mission to Pluto. The Kuiper Belt is a debris field of icy bodies left over from the solar system's formation 4.6 billion years ago.
Once the New Horizons craft flies by Pluto in mid-2015, the team's goal is to get NASA's approval to retarget the probe to fly by a KBO, which might only measure 20 miles across.
To test the feasibility of finding New Horizons targets with Hubble, a set of pilot Hubble observations were executed in June 2014. After a swift and intensive data analysis of approximately 200 Hubble images, the New Horizons team met the pilot program criterion of finding a minimum of two KBOs.
Multiple exposures taken with Hubble tracked the KBOs moving against the background field of stars in the summer constellation Sagittarius.
The image at left shows a KBO at an estimated distance of approximately 4 billion miles from Earth. Its position noticeably shifts between exposures taken approximately 10 minutes apart. The image at right shows a second KBO at roughly a similar distance.
The positions of these newly discovered objects are not consistent with any KBOs discovered previously. In reality, they are too faint to have been seen with ground-based telescopes (magnitudes 26.8 and 27.3, respectively).
It will be many weeks before the team can establish whether either of these pilot-program KBOs is a suitable target for New Horizons to visit, but their discovery provides sufficient evidence that a wider search to be executed with Hubble will find an optimum object.