Using data from NASA’s New Horizons mission as well as ESA’s Rosetta mission, scientists at the Southwest Research Institute have developed a new theory about how Pluto may have formed at the edge of our solar system.
Scientists at the institute call it the ‘the giant comet’ cosmochemical model of Pluto formation. Scientists say that t the heart of their study published in Icarus is the nitrogen-rich ice in Sputnik Planitia, a large glacier that forms the left lobe of the bright Tombaugh Regio feature on Pluto’s surface.
They say that there is an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta.
In addition to the comet model, scientists also investigated a solar model, with Pluto forming from very cold ices that would have had a chemical composition that more closely matches that of the Sun.
Scientists needed to understand not only the nitrogen present at Pluto now — in its atmosphere and in glaciers — but also how much of the volatile element potentially could have leaked out of the atmosphere and into space over the eons. They then needed to reconcile the proportion of carbon monoxide to nitrogen to get a more complete picture. Ultimately, the low abundance of carbon monoxide at Pluto points to burial in surface ices or to destruction from liquid water.