Pluto And Its Moon Came Together With 'Kiss And Capture', Study Says

 

Pluto's moon Charon, as imaged by the New Horizons spacecraft. (NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker)

It's possible that Pluto and Charon's romance began with a kiss.

According to a recent study, the dwarf planet and its hardly smaller moon most likely collided billions of years ago, briefly joining forces before splitting off to form a stable, long-term orbital dance.

This "kiss and capture" process runs counter to earlier hypotheses regarding Charon's origin, which suggested that it must have developed from a massive impact similar to the one thought to have created the Moon.

According to planetary scientist Adeene Denton of the University of Arizona, "the majority of planetary collision scenarios are categorized as 'hit and run' or 'graze and merge'."

"What we've discovered is something entirely different – a 'kiss and capture' scenario where the bodies collide, stick together briefly and then separate while remaining gravitationally bound."

For planets within the Solar System's frost line, or the distance from the Sun at which gasses like water condense into frozen grains, the models used to comprehend the massive collision that created Earth's Moon perform exceptionally well. This distance is around five times that of the Sun and Earth.

Earth and the Moon behave more like fluids during a massive impact because they are warmer and more pliable, particularly during the early Solar System's 4.5 billion-year-old breakup.

However, figuring out Pluto's and Charon's characteristics is a little challenging. With a circular orbit around a shared center of gravity, they are separated by around 19,500 kilometers and have diameters of 2,376 kilometers (1,476 miles) and 1,214 kilometers, respectively.

Although it is difficult to reconcile Charon's size and orbit with this hypothesis, the fact that Pluto and Charon's orbital axes are nearly identical suggests that they were both spun out of the same revolving chaos after a collision.

Pluto and Charon, on the other hand, are smaller than Earth and the Moon (the Moon is 3,475 kilometers across) and more colder due to their composition of rock and ice. The scientists discovered that Pluto and Charon behaved differently when they took into consideration the strength of these materials in comparison to the big, warm, mushy Earth and Moon.

Rather than a massive rock colliding with Pluto, combining, and launching a massive amount of debris into space that eventually merged into Charon, the two bodies would have merged and stayed mostly unaltered because of their strength and density, which stopped them from causing more damage to one another.

Rather, as a contact binary, Pluto and Charon would have remained together for a while, similar to the two lobes of the far-off Solar System object Arrokoth, according to the team's simulations. Both items would have maintained their identity when they parted again since they would have stayed largely intact and had the same composition.

The two bodies would eventually drift apart to their present orbital axis, shape, and distance. The two bodies' reported orbital characteristics were flawlessly reproduced in the team's simulations.

New Horizons image of Pluto (right) and Charon (left). (NASA/JHUAPL/SwRI)

"This result is interesting since the model parameters that catch Charon ultimately place it in the correct orbit. Erik Asphaug, a planetary scientist at the University of Arizona, argues, "You get two things right for the price of one."

The discovery implies that planetary bodies and their companions are more diverse and exciting to develop than we previously thought, and that ignoring physical characteristics can seriously hinder our ability to fully comprehend how the physical universe functions.

It also provides astronomers with a new tool to help them comprehend how Pluto, a bizarre and rich world unlike any other in the Solar System, has changed throughout time.

"We're particularly interested in understanding how this initial configuration affects Pluto's geological evolution," Denton explains. "The heat from the impact and subsequent tidal forces could have played a crucial role in shaping the features we see on Pluto's surface today."

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