A team of scientists at Northern Arizona University recently revealed that the frozen surface of Eris, the largest-known dwarf planet orbiting the sun, is predominantly covered in nitrogen ice, similar to the surface of Pluto.
Stephen Tegler, NAU professor of physics and astronomy and lead author of “Methane and Nitrogen Abundances on Eris and Pluto,” presented the team’s findings Oct. 5 at the 42nd annual meeting of the American Astronomical Society’s Division for Planetary Sciences in Pasadena, Calif. Tegler’s research was completed in partnership with experts from Missouri State University and Flagstaff’s Lowell Observatory,
The paper recently was accepted for publication in the Astrophysical Journal.
Tegler, along with a team of researchers that included NAU graduate students Matt Abernathy, David Evans, Chet Maleszewski and undergrad Zach Thompson, utilized two years of work conducted in the new ice lab on the Flagstaff campus. The research integrated astronomical observations of Eris from the Multiple Mirror Telescope Observatory from Mount Hopkins, Ariz., and of Pluto from Steward Observatory from Kitt Peak, Ariz.
“There are only a handful of such labs doing this kind of work in the world,” Tegler said. “By studying surfaces of icy dwarf planets, we hope to get a better understanding of the processes that affect their surfaces.”
“By combining the astronomical data and laboratory data, we found about 90 percent of Eris’s icy surface is made up of nitrogen ice and about 10 percent is made up of methane ice, which is not all that different from Pluto,” said David Cornelison, coauthor and physicist at Missouri State University.NAU’s ice lab grew ice samples of methane, nitrogen, argon, methane-nitrogen mixtures and methane-argon mixtures in a vacuum chamber at temperatures as low as minus 390 degrees Fahrenheit to simulate the planets’ cold surfaces. Light passed through the samples revealed the “chemical fingerprints” of molecules and atoms, which were compared to telescopic observations of sunlight reflected from the surfaces of Eris and Pluto.
Discovered in 2003 and named after the goddess of warfare and strife, Eris hit the astronomical map with the largest diameter of any known dwarf planet, consequently unseating its smaller neighbor Pluto from “official” to dwarf planet status. Since then, Eris has held the attention of astronomers and physicists as they strive to gain a better understanding of the farthest reaches of the solar system.
The recent findings will directly enhance NASA’s New Horizons spacecraft mission, currently scheduled to fly by Pluto in 2015, lending greater value to the continued research of Eris and Pluto.