Charon, the moon of the Pluto, may be saving the icy dwarf planet from decay, a new study suggests. According to the study, Charon may be reducing the loss of atmosphere of Pluto significantly by creating a shield.
Pluto's moon may also be redirecting much of the solar wind around and away, thus saving the planet's atmosphere, the study said.
Charon's size and proximity makes the relationship between Pluto and Charon one of the more unusual interactions in the solar system. More than half of Pluto's diameter, Charon orbits only 19,312 kilometres away.
Picture our moon thrice closer to Earth and as large as Mars to put that into perspective, researchers from the Georgia Institute of Technology in the US said.
The study adds insight into the relationship of Pluto and Charon and shows how it affects the continuous stripping of Pluto's atmosphere by solar wind.
The research suggests that the moon can significantly reduce the atmospheric loss when the Charon is positioned between the Sun and Pluto.
"Charon does not always have its own atmosphere. But when it does, it creates a shield for Pluto and redirects much of the solar wind around and away," said Carol Paty, a Georgia Tech associate professor.
This barrier creates a more acute angle of bow shock of Pluto, reducing the deterioration of the atmosphere.
Charon has a minor effect on the interaction of the solar wind with the Pluto when Charon doesn't have an atmosphere or when it is behind or next to Pluto.
The predictions of the study were carried out before the New Horizons probe. They collected and returned data to Earth, is consistent with the measurements made by the spacecraft about Pluto's atmospheric loss rate.
At the time of the study, the previous estimates were at least 100 times higher than the actual rate.
According to John Hale, the Georgia Tech student who co-led the study with Paty, the Pluto system is a window into our origins because Pluto has not been subjected to the same extreme temperatures as objects in closer orbits to the Sun.
"As a result, Pluto still has more of its volatile elements, which have long since been blown off the inner planets by solar wind," Hale said.
"Even at its great distance from the Sun, Pluto is slowly losing its atmosphere. Knowing the rate at which Pluto's atmosphere is being lost can tell us how much atmosphere it had to begin with, and therefore what it looked like originally. From there, we can get an idea of what the solar system was made of during its formation," he said.
The study affirms a popular hypothesis of Charon. The areas of discolouration near its lunar poles are likely caused by magnetised particles that have been shorn from Pluto's atmosphere, researchers said.
These particles have accumulated and settled on Charon over billions of years, particularly when it is downstream of Pluto.
The research was published in the journal Icarus.
(With inputs from PTI)