Study Sheds Light On The Mystery Of Pluto’s Icy Heart

When scientists saw Pluto for the first time, they noticed a two-loved formation on its surface, which looked like an icy heart. Now, a new study provides an insight on how exactly did the dwarf planet got its broken heart.

One of the two lobes, the western lobe, received more attention from researchers. Dubbed as the Sputnik Planitia, it is a deep basin containing carbon monoxide, frozen nitrogen and methane, appearing opposite Charon, the dwarf planet's large, tidally locked moon.

The discovery of Sputnik Planitia's unique attributes baffled scientists and left them with a number of scenarios for its formation. Many suspect that the western lobe of the icy heart was formed long ago by the impact of a large Kuiper Belt object onto the dwarf planet.

Now, a team of scientists at the University of Maryland suggests that the western lobe formed early in the history of the planet. The attributes it possesses are inevitable consequences of evolutionary processes.

Published in the journal Nature, the study shows that this nitrogen ice cap may have formed early on when Pluto was still spinning rapidly. This new scenario requires no impact at all.

A New Model

Using a model developed by one of the researchers, Douglas Hamilton, professor of astronomy at the University of Maryland, he found that the first location of the western lobe could be explained by Pluto's strange climate, covered with methane frost, nitrogen ice and a giant glacier, and its spin axis, which is tilted by about 120 degrees.

Previous studies on the dwarf planet have spurred a scenario that it could have been formed from an asteroid impact. However, the new study suggests that this could not have been the case. To investigate, they used computer simulations and found that the swelling ice deposits concentrated into a single and huge ice cap.

As the frosts merged, more sunlight was reflected, making the temperatures to decrease and more ice to form, and the cycle repeats.

Called the runaway albedo effect, this positive feedback phenomenon would eventually lead to a single enormous ice cap, like the one found on Pluto's surface. However, the sheer weight of the ice ultimately caused the dwarf planet's crust to crack under the strain, leaving a huge basin.

"The main difference between my model and others is that I suggest that the ice cap formed early when Pluto was still spinning quickly and that the basin formed later and not from an impact," Hamilton said in a press release by Phys.org.

"The ice cap provides a slight asymmetry that either lock toward or away from Charon when Pluto's spin slows to match the orbital motion of the moon," he added.