Sunday, May 21, 2017

The Mysteries of DeeDee: One of the Solar System’s Most Distant Object Studied by Astronomers

Artist concept of the planetary body 2014 UZ224, more informally known as DeeDee. Credit: Alexandra Angelich (NRAO/AUI/NSF)

Lurking somewhere beyond Neptune, the planetary body 2014 UZ224, nicknamed DeeDee, is one of the most distant objects in the solar system. Although DeeDee was lately studied by astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, this faraway dim object still holds many mysteries waiting to be uncovered.

2014 UZ224 is a 635-kilometer-wide trans-Neptunian object (TNO), orbiting the sun every 1,136 years. The object was detected by a team of astronomers led by David Gerdes of the University of Michigan, using the 4-meter Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile as part of ongoing observations for the Dark Energy Survey. They announced their discovery in October 2016 and informally dubbed the newly found TNO DeeDee, which is short for Distant Dwarf.

Recent observations of DeeDee conducted with ALMA allowed Gerdes and his team to reveal the object’s fundamental orbital parameters as well as its size and albedo. Based on the new findings, the researchers assume that 2014 UZ224 is most likely a dwarf planet with a mixed ice-rock composition. However, more observations are needed in order to draw final conclusions about the real nature of this distant TNO.

“We expect to make further optical observations of DeeDee with the Blanco 4-meter telescope during the Dark Energy Survey's upcoming observing season, from August 2017 to February 2018. These observations will help refine DeeDee's orbital parameters,” Gerdes told Astrowatch.net.

DeeDee’s orbital and physical properties could reveal important insights about the formation of planets, including Earth. Such objects are leftovers from the formation of the solar system, thus could be real treasure troves of information regarding the history and evolution of celestial bodies.

DeeDee is currently about 92 astronomical units (AU) away from the sun. This is roughly three times Pluto's current distance. The object will reach it’s perihelion distance of about 38 AU in the year 2142, when due to its proximity it could be studied by a dedicated probe. Hence, the only opportunity now available to study this TNO is to employ ground-based telescopes or space observatories flying in Earth’s orbit.

“A dedicated mission to study this object from close range is not feasible at this time. DeeDee will reach its perihelion distance of 38 AU in the year 2142. Perhaps at that point in the distant future a dedicated mission will be both practical and scientifically interesting,” Gerdes noted.

TNOs are icy bodies in orbit beyond Neptune. Observations of these objects could provide better understanding of accretion and evolution processes that governed planetary formation in our solar system as well as in other dusty star discs. Currently, NASA’s New Horizons spacecraft, after completing its flyby of Pluto, is on its way to study such celestial body designated 2014 MU69. This object is about 44 AU away from the sun. New Horizons is expected to arrive there in January 2019.

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