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A new type of aurora has been spotted on Mars, and solar wind waves could be to blame, reveals a new study.
Unlike auroras on Earth, which are caused by electrons and are usually observed near the poles, the aurorae of Mars are triggered by an influx of protons and occur over much of the red planet, where the aurora is very hard to see. .
Using the ultraviolet imaging spectrograph on NASA's Mars Atmosphere and Volatile Evolution (MAVEN) orbiter, astronomers have observed that, on occasion, ultraviolet light from the Hydrogen gas in the upper atmosphere of Mars would mysteriously lighten for a few hours. These lightening events occurred at the same time that the orbiter's Solar Wind Ion Analyzer (SWIA) instrument measured an increase in solar wind protons (charged particles released by the sun), according to the study. [Gorgeous Auroras Could Light Up Entire Martian Sky]
This image shows the formation of a proton aurora at Mars. A solar wind proton is moving towards Mars, reaching a hydrogen cloud surrounding the planet and flying an electron from one of these hydrogen atoms to become neutral. The atom can then traverse the shock of the magnetic arc around Mars because it no longer carries any charge and it collides with the gas molecules in the Mars atmosphere for produce ultraviolet light. Credit: Dan Gallagher / NASA / MAVEN / Goddard Space Flight Center
In general, the "arc shock" of Mars – a magnetic obstacle surrounding the planet – would divert the charged particles from the solar wind. However, researchers have discovered that, in this case, charged particles "steal" electrons to sneak into the upper atmosphere of the planet. "As we approach Mars, the protons entering the solar wind turn into neutral atoms." Justin Deighan, a researcher at the University of Colorado's Boulder Laboratory of Atmospheric and Space Physics and lead author of the new study, said in a statement from NASA that electrons were flying from the outer edge of the huge hydrogen cloud that surrounds the planet. Monday (23 July). "The arc shock can only divert charged particles, so these neutral atoms go straight on."
The Mars MAVEN orbiter observed a proton aurora around the red planet. This diagram shows how changes in the solar wind impact visible emissions.
Source: Anil Rao / NASA / MAVEN / University of Colorado / LASP
These unusual proton auroras occur much more frequently on Mars than on Earth, largely because of the Earth's strong magnetic field. As a result, proton auroras can also occur on other worlds that do not have their own magnetic fields, such as Venus or Titan, the moon of Saturn, NASA officials said in a statement. communicated. These two bodies also have an abundance of hydrogen in their upper atmosphere, which means that there are plenty of electrons available to neutralize charged solar wind incoming particles.
"The proton aurorae of Mars are more than a light show," said SWIA Principal Investigator Jasper Halekas, an badociate professor in the Department of Physics and Astronomy of the US. University of Iowa. "They reveal that the solar wind is not completely deflected around Mars, showing how the protons of the solar wind can sneak into the atmosphere, deposit energy there, and even increase it. hydrogen content. "
23 in the journal Nature Astronomy.
Follow Samantha Mathewson @ Sam_Ashley13 . Follow us on @Spacedotcom Facebook and Google+. Original article on Space.com
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