You expect an aurora on Mars and MAVEN spots two at once • The Register

A coronal mass ejection from our Sun sent a shower of charged particles to Mars, generating two types of ultraviolet auroras that astronomers had never seen at the same time before.

It’s the first time such a solar wind has been detected by the Mars orbiter MAVEN – it’s the Mars Atmosphere and Volatile Evolution probe – in its eight-year run, NASA said. On Earth, auroras are caused when highly energetic charged particles spewed out by the Sun crash into particles in our atmosphere. Our planet’s magnetic field directs the solar wind towards the polar regions to create the familiar aurora borealis and australia.

Auroras on Mars are a more mysterious phenomenon. The Red Planet doesn’t have a magnetic field these days and has a very weak and thin atmosphere, but it still produces dazzling displays of light streaking across its sky. Scientists are still trying to understand the exact mechanisms that power the Martian aurora. Now NASA’s MAVEN spacecraft has provided more data and detected not one but two types of auroras occurring simultaneously.

On August 27, an active sunspot excluded a series of coronal mass ejections (CME). The event sent a wave of charged particles out into space that rained down on Mars, creating proton aurora and diffuse aurora at the same time.

A diffuse aurora is cause by energetic electrons colliding and exciting particles in Mars’ atmosphere, causing them to issue UV light.

A proton aurora only appears when conditions are just after a Martian dust storm ends. Dust storms warm the atmosphere, pushing water vapor to higher altitudes where molecules are split into their oxygen and hydrogen parts. When a gust of solar wind hits the hydrogen atoms, they interact and release rays of ultraviolet light.

Sumedha Gupta, a postdoctoral researcher in physics at the University of Colorado at Boulder, first noticed both types of aurora during a routine check of MAVEN data. “I was so surprised to see proton auroras at the same time as diffuse auroras, because it had never happened before,” she said. said in a report. “They both increase with solar activity, so hopefully that will continue to happen.”

The CME in August produced one of the brightest solar energy events observed by MAVEN to date. Astronomers believe the spacecraft will likely detect even more Martian auroras as the Sun approaches its solar maximum in 2024 to 2025, and solar activity peaks during its 11-year cycle. The Sun will spit out more CME and shower Mars with more solar energetic events to create a green sway in its sky.

“It’s exciting to still see ‘firsts’ like these simultaneous auroras for so many years after the mission began,” said Shannon Curry, MAVEN principal investigator at the University of California, Berkeley. “We have so much to learn about the atmosphere and how solar storms affect the Red Planet. Our team looks forward to observing the most extreme conditions for the next few years during the lifetime of the MAVEN mission.”

In May, the spacecraft was restored from safe mode after engineers managed to fix a navigation systems issue that has plagued MAVEN for months. MAVEN should continue to operate for the next decade. ®

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