Dwarf planet discovered beyond Pluto joins solar system

Out beyond Neptune, past Pluto, through the chaos of the Kuiper belt to a point 8.5 billion miles from the sun, a new dwarf planet has just joined our solar system.

The Iowa-sized object, which is about half as big as Pluto and twice as distant, was described Tuesday in the International Astronomical Union’s Minor Planet Electronic Circulator. It joins a growing list of dwarf planets known to populate the solar system: Ceres, Haumea, Makemake, Eris and Pluto. It’s suspected there could be at least 100 more.

The “trans-Neptunian object,” known for now as 2014 UZ224, was discovered by University of Michigan astrophysicist David Gerdes and a team of researchers.

Gerdes is part of an international team of scientists working on the Dark Energy Survey — an effort to map the universe and elucidate some of its mysteries, particularly, why the expansion of the universe is accelerating. To do a dark energy survey, you need a dark energy camera, so the DES built a wide-angle camera in Cerro Tololo, Chile, that’s capable of imaging of the whole sky.

It took two years of careful tracking to confirm the discovery and map out 2014 UZ224’s orbit. Its exact path is still unclear, because the planet takes more than 1,000 years to complete a single loop of the sun. But it’s believed that 2014 UZ224 is the third most-distant object in the solar system.

Gerdes told NPR that it’s possible some astronomers might dispute 2014 UZ224’s dwarf planet designation. The distant body is small, even for a dwarf planet.

But the term applies for now. Meanwhile, he and his colleagues are on to bigger things: looking for the mysterious Planet Nine, whose existence was speculated about in the Astronomical Journal earlier this year.