Pluto and its moon, Charon
A new study suggests that the dwarf planet and its moon began their orbital dance with the “kiss and capture” mechanism.
Billions of years ago, before separating in a stable, long-lasting orbital dance, Pluto and its moon, Charon, came together in a collision that brought them together, until they separated in a orbital dance.
A new one published in Nature this Monday suggests so, going against the hitherto established theory that this duo was formed through a giant impact, similar to what happened between the Moon and the Earth.
“Most planetary collision scenarios are classified as ‘hit and run’ or ‘bump and melt,’” says University of Arizona planetary scientist, Adeene Dentonhas .
“What we discovered is something completely different – a ‘kiss and capture’ scenario in which bodies collide, stay together for a short time and then separate, remaining gravitationally linked”, explains the researcher.
The models used to understand the giant impact that formed Earth’s Moon work very well for bodies within the Solar System’s ice line. But the situation becomes more complicated when analyzing Pluto and Charon.
Their diameters are (1,476 miles) and , respectively, and they are separated by a distance of about 19,500 kilometers, with a circular orbit around a mutual center of gravity.
The two stars are also much smaller and much colder, made of rock and ice. And that’s why there couldn’t have been a collision like the Earth and the Moon, the researchers argue.
This would cause a massive collision that would launch a huge amount of debris into space. But no — they both stayed intact.
Instead, the team’s simulations show that Pluto and Charon would have stayed together for a time as what is known as a contact torque. Both objects would have remained relatively intact, with their compositions unchanged. Over time, the two bodies will move towards each other until they reach their current orbital distance, shape and axis.
“The most interesting thing about this study is that the model parameters that work to capture Charon end up placing it in the correct orbit. Two things are right for the price of one,” he says. Erik Asphaug, scientist at the University of Arizona.
Now, researchers want to go further and use the findings to study the astrogeologybetter understanding the geological evolution of the dwarf planet.
“We are particularly interested in understanding how this initial configuration affects the geological evolution of Pluto“, adds Denton. “THE impact heat and tidal forces subsequent events may have played a crucial role in forming the features we see on Pluto’s surface today.”
