Nav: Home

How a moon slows the decay of Pluto's atmosphere

January 09, 2017

Pluto's relationship with its moon Charon is one of the more unusual interactions in the solar system due to Charon's size and proximity. It's more than half of Pluto's diameter and orbits only 12,000 or so miles away. To put that into perspective, picture our moon three times closer to Earth, and as large as Mars.

A new study from the Georgia Institute of Technology provides additional insight into this relationship and how it affects the continuous stripping of Pluto's atmosphere by solar wind. When Charon is positioned between the sun and Pluto, the research indicates that the moon can significantly reduce atmospheric loss.

"Charon doesn't always have its own atmosphere," said Carol Paty, a Georgia Tech associate professor in the School of Earth and Atmospheric Sciences. "But when it does, it creates a shield for Pluto and redirects much of the solar wind around and away."

This barrier creates a more acute angle of Pluto's bow shock, slowing down the deterioration of the atmosphere. When Charon doesn't have an atmosphere, or when it's behind or next to Pluto (a term scientists call "downstream"), then Charon has only a minor effect on the interaction of the solar wind with Pluto.

The study's predictions, performed before the New Horizons probe collected and returned data to Earth, is consistent with the measurements made by the spacecraft about Pluto's atmospheric loss rate. Previous estimates at the time of the study were at least 100 times higher than the actual rate.

The research is currently published in a special Pluto issue of the journal Icarus.

John Hale is the Georgia Tech student who co-led the study with Paty. He says the Pluto system is a window into our origins because Pluto hasn't 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."

Hale and Paty also say their study affirms a popular hypothesis of Charon. The areas of discoloration near its lunar poles are likely caused by magnetized particles that have been shorn from Pluto's atmosphere. These particles have accumulated and settled on Charon over billions of years, particularly when it is downstream of Pluto.
-end-
The project is supported by NASA grant NNX11AM40G. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsors.

Georgia Institute of Technology

Related Solar System Articles:

From rocks in Colorado, evidence of a 'chaotic solar system'
Plumbing a 90 million-year-old layer cake of sedimentary rock in Colorado, a team of scientists from the University of Wisconsin-Madison and Northwestern University has found evidence confirming a critical theory of how the planets in our solar system behave in their orbits around the sun.
Why are there different 'flavors' of iron around the Solar System?
New work from Carnegie's Stephen Elardo and Anat Shahar shows that interactions between iron and nickel under the extreme pressures and temperatures similar to a planetary interior can help scientists understand the period in our Solar System's youth when planets were forming and their cores were created.
Does our solar system have an undiscovered planet? You can help astronomers find out
ASU's Adam Schneider and colleagues are hunting for runaway worlds in the space between stars, and citizen scientists can join the search with a new NASA-funded website.
Rare meteorites challenge our understanding of the solar system
Researchers have discovered minerals from 43 meteorites that landed on Earth 470 million years ago.
New evidence on the formation of the solar system
International research involving a Monash University scientist is using new computer models and evidence from meteorites to show that a low-mass supernova triggered the formation of our solar system.
Planet Nine could spell doom for solar system
The solar system could be thrown into disaster when the sun dies if the mysterious 'Planet Nine' exists, according to research from the University of Warwick.
Theft behind Planet 9 in our solar system
Through a computer-simulated study, astronomers at Lund University in Sweden show that it is highly likely that the so-called Planet 9 is an exoplanet.
Studying the solar system with NASA's Webb Telescope
NASA's James Webb Space Telescope will look across vast distances to find the earliest stars and galaxies and study the atmospheres of mysterious worlds orbiting other stars.
'This solar system isn't big enough for the both of us.' -- Jupiter
It's like something out of an interplanetary chess game. Astrophysicists at the University of Toronto have found that a close encounter with Jupiter about four billion years ago may have resulted in another planet's ejection from the Solar System altogether.
IBEX sheds new light on solar system boundary
In 14 papers published in the October 2015 Astrophysical Journal Supplement, scientists present findings from NASA's Interstellar Boundary Explorer, or IBEX, mission providing the most definitive analyses, theories and results about local interstellar space to date.

Related Solar System Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#514 Arctic Energy (Rebroadcast)
This week we're looking at how alternative energy works in the arctic. We speak to Louie Azzolini and Linda Todd from the Arctic Energy Alliance, a non-profit helping communities reduce their energy usage and transition to more affordable and sustainable forms of energy. And the lessons they're learning along the way can help those of us further south.