in a joint effort between NASA’s MAVEN spacecraft and the United Arab Emirates Mars Mission (EMM), scientists have observed an unusually chaotic interaction between the solar wind and the upper atmosphere of Mars, creating a unique ultraviolet aurora.

The phenomenon represents an unusual occurrence in Martian space weather, and scientists are excited to take advantage of future collaborations between spacecraft to keep an eye out for repeat events.

Mars ultraviolet aurora

The strange irregular aurora created by the solar wind was observed twice, on August 11 and August 30 this year. A similar aurora has been observed regularly since 2018, but it usually occurs in a smooth, even band that covers the planet. Last month’s aurora was irregular, variable and local, on the contrary.

It’s a specific type of aurora called a proton aurora and it occurs on the day side of the planet when hydrogen atoms from the Sun, stripped of their electrons, shoot toward the red planet and penetrate the “bow shock,” a magnetic barrier that naturally protects the atmosphere of Mars. Some of the protons may bypass the bow shock by stealing electrons from the busy region of space around Mars, becoming neutral and breaking up to hit the upper atmosphere. The result is an ultraviolet aurora that, until now, always seemed to occur as a coherent whole on the face of Mars, but has now been seen in distinct patches.

Proton auroras also occur on Earth, but cannot be seen by human eyes and are rarer due to Earth’s stronger magnetic field.

Observations from both MAVEN and EMM were needed to understand what was happening. EMM’s Emirates Mars Ultraviolet Spectrograph (EMUS) constantly scans the planet’s upper atmosphere, looking for evidence of atmospheric escape into space and changes in composition. Its detector is perfect for capturing the ultraviolet light caused by the proton aurora.

plasma everywhere

Meanwhile, MAVEN captures data in situ, “feeling” the solar wind plasma as it passes by with a magnetometer and ion analyzers.

When the EMM data were compared with those from MAVEN, it became clear that the patchy proton aurora was the result of a highly perturbing plasma environment at the time of the events.

Mike Chaffin of the University of Colorado, Boulder explained that “the EMM observations suggested that the aurora was so widespread and disorganized that the plasma environment around Mars must have been truly perturbed, to the point that the solar wind was directly impacting the upper atmosphere wherever it went.” we observe auroral emission. …By combining EMM aurora observations with MAVEN measurements of the auroral plasma environment, we can confirm this hypothesis and determine that what we were seeing was essentially a map of where the solar wind was hitting the planet.”

Essentially, it was a temporary breakdown of Mars’ natural defenses against solar radiation as particles were able to take advantage of chaotic space weather to find a way into the planet’s atmosphere.

MAVEN arrived on Mars in 2014 and joined EMM in 2021. There are more than half a dozen Mars-orbiting probes, each with different specialties and capabilities. Working together, they can help us understand Mars in ways they can’t on their own, including studying its unique auroras.

This article was originally published on universe today by Scott Alan Johnston. Read the original article here.