"1994 JR1" is a 145-km-wide Kuiper Belt object (KBO) orbiting more than 5 billion km from the Sun.
Taken from the spacecraft's Long Range Reconnaissance Imager (LORRI) in April, the images shatter New Horizons' own record for the closest-ever views of this KBO in November 2015 when New Horizons detected "JR1" from 280 million km away.
The observations contain several valuable findings.
"Combining the November 2015 and April 2016 observations allows us to pinpoint the location of JR1 to within 1,000 km, far better than any small KBO," said Simon Porter from Southwest Research Institute (SwRI) in Boulder, Colorado.
The more accurate orbit also allows the science team to dispel a theory, suggested several years ago, that JR1 is a quasi-satellite of Pluto.
The team also determined the object's rotation period, observing the changes in light reflected from JR1's surface to determine that it rotates once every 5.4 hours (or a JR1 day).
"That's relatively fast for a KBO. This is all part of the excitement of exploring new places and seeing things never seen before," added science team member John Spencer from SwRI in a Nasa statement.
The observations are great practice for possible close-up looks at about 20 more ancient Kuiper Belt objects that may come in the next few years.
New Horizons flew through the Pluto system on July 14, making the first close-up observations of Pluto and its family of five moons.
The spacecraft is on course for an ultra-close flyby of another Kuiper Belt object, "2014 MU69", on January 1, 2019.
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