Observations of the dwarf planet 2014 MU69, the "forerunner" of Pluto and the next target of the New Horizons probe, have shown that it is unexpectedly small in size or is a swarm of asteroids, NASA reports.
“These results were extremely interesting to us. The fact that we carried out all the planned observations and did not find any traces of the planet in any case suggests that MU69 is either very bright and small, or that it is a pair of dwarf planets or a swarm of small celestial bodies that have survived to us since the time the birth of the solar system,”says Alan Stern, head of the New Horizons mission.
In October and early November last year, after transmitting the most interesting images of Pluto and its moons and important scientific data, the New Horizons probe performed a series of four acceleration and maneuvers that will allow it to meet in January 2019 with Kuiper object 2014 MU69.
The maneuvers put the probe on a trajectory that leads it into the depths of the Kuiper belt - the solar system's "dump of building materials" on its farthest outskirts, inhabited by many asteroids, planetary embryos and Pluto's "cousins", dwarf planets.
New Horizons covered about half the way to 2014 MU69, but scientists are already preparing for the "rendezvous" of the probe with the alleged sample of the primary mother of the solar system, studying it using space and ground-based telescopes.
According to Stern, astronomers have a unique opportunity to study the size, chemical composition and several other properties of Pluto's “forerunner” by observing how 2014 MU69 passes through the disk and obscures the light of a star hundreds of light years away from the Sun.
By observing how much the star dims, scientists hoped to complement our understanding of what this dwarf planet looks like and what to expect for New Horizons as it approaches it.
In total, the New Horizons team and their volunteers received about 100 thousand images of the star, in none of which they did not manage to notice visible traces of the fact that 2014 MU69 made it fade.
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This means that the diameter of the dwarf planet is noticeably less than the assumed 40 kilometers, it is close to 20 kilometers or even more modest values. In this case, the surface of 2014 MU69 should not be dark red, as scientists assume today, but bright white, well reflecting light.
There is also an alternative explanation for all this - 2014 MU69 could be a pair of dwarf planets, a kind of miniature version of Pluto and Charon, or in general a swarm of small asteroids moving together.
Both scenarios do not make 2014 MU69 less interesting to study, since the likelihood of a rendezvous with the primitive "building materials" of the solar system will be much higher in these cases, Stern notes.
