Scientists discover a comet that has its own aurora

Hyperaxion Sep 23, 2020

The aurora was spotted on comet 67P/Churyumov-Gerasimenko. This is the first time that an aurora is observed on an object other than planets and moons.

Data obtained by the European Space Agency’s (ESA) Rosetta mission revealed that comet 67P/Churyumov-Gerasimenko has its own ultraviolet aurora.

Scientists discover a comet that has its own aurora
Comet 67P/Churyumov-Gerasimenko (Credit: ESA / Rosetta / NAVCAM).

In a study recently published in the journal Nature Astronomy, astronomers responsible for the discovery say that this is the first time that an aurora has been observed on an object other than a planet or a moon.

“The glow surrounding 67P/C-G is one of a kind. By digging into data from numerous instruments on Rosetta and linking them together, we’ve discovered that this glow is auroral in nature,” said lead author Marina Galand of Imperial College London, UK.

“It’s caused by a mix of processes, some seen at Jupiter’s moons Ganymede and Europa and others at Earth and Mars.”

Electrons from the Sun interact with the gas around the comet, separating water from other molecules. The atoms that emerge from this process emit a distinctive ultraviolet light, which is invisible to the naked eye, and has the shortest wavelength of radiation in the ultraviolet spectrum.

“These electrons then interact with molecules in the coma to produce the auroral glow. The process by which the electrons are accelerated is similar to some of the processes that drive auroras at Earth and Mars, despite 67P/C-G lacking an intrinsic magnetic field,” Galand explained.

“In fact, the magnetic environments of moons, planets, and comets are all very different, so it’s exciting and intriguing that we see auroras at all of them.”

Studying this aurora will allow scientists to learn how solar wind particles change over time, which is crucial for understanding space weather throughout the Solar System.

As the scientists explain, by learning more about how radiation from the Sun affects the space environment, this information can be used to improve satellite and spacecraft protection systems.

“Auroras are inherently exciting – and this excitement is even greater when we see one somewhere new, or with new characteristics,” said co-author Matt Taylor.

“This multi-instrument analysis brings together more pieces of the puzzle in our understanding of both auroras throughout the Solar System, and of the various phenomena we see around comets.”

Related topics:

Aurora borealis Comets


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