New images from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft show the ultraviolet glow from the Red Planet’s atmosphere in detail, revealing dynamic, previously invisible behavior. They include the first images of ‘nightglow’ from nitric oxide. Additionally, dayside images show how ozone amounts change over the seasons and how afternoon clouds form over Martian volcanoes.
This image of the Mars night side from MAVEN’s IUVS instrument shows UV emission from nitric oxide. The emission is shown in false color with black as low values, green as medium, and white as high. These are the first such images obtained at Mars. Nightglow is a common planetary phenomenon in which the sky faintly glows even in the complete absence of external light. These emissions track the recombination of atomic nitrogen and oxygen produced on the dayside, and reveal the circulation patterns of the atmosphere. The splotches, streaks and other irregularities in the image are indications that atmospheric patterns are extremely variable on nightside. The portion of the globe without data lies on the dayside, making NO emission from recombination undetectable. The inset shows the viewing geometry on the planet. MAVEN obtained this image on May 4, 2016 during late winter in Mars’ southern hemisphere. Image credit: NASA / MAVEN / University of Colorado.
“MAVEN obtained hundreds of such images in recent months, giving some of the best high-resolution ultraviolet (UV) coverage of Mars ever obtained,” said MAVEN co-investigator Dr. Nick Schneider, a researcher in the Department of Astrophysical and Planetary Sciences at the University of Colorado, Boulder.
The images were taken by MAVEN’s Imaging UltraViolet Spectrograph (IUVS).
Nightside images show UV ‘nightglow’ emission from nitric oxide. Nightglow is a common planetary phenomenon in which the sky faintly glows even in the complete absence of external light.
Planetary researchers predicted nitric oxide nightglow at Mars, and prior missions detected its presence, but MAVEN has returned the first images of this phenomenon.
Splotches and streaks appearing in these images occur where nitric oxide recombination is enhanced by winds.
Such concentrations are clear evidence of strong irregularities in Mars’ high altitude winds and circulation patterns. These winds control how the Martian atmosphere responds to its very strong seasonal cycles.
These first images will lead to an improved determination of the circulation patterns that control the behavior of the atmosphere from 37 to 62 miles (60 – 100 km) high.
This UV image near the Martian south pole was taken on July 10, 2016 and shows the atmosphere and surface during southern spring. Darker regions show the planet’s rocky surface and brighter regions are due to clouds, dust and haze. The white region centered on the pole is frozen carbon dioxide on the surface. Pockets of ice are left inside craters as the polar cap recedes in the spring, giving its edge a rough appearance. High concentrations of atmospheric ozone appear magenta in color, and the wavy edge of the enhanced ozone region highlights wind patterns around the pole. Image credit: NASA / MAVEN / University of Colorado.
Dayside images show the atmosphere and surface near the Martian south pole in unprecedented UV detail. They were obtained as spring comes to the southern hemisphere.
Ozone is destroyed when water vapor is present, so ozone accumulates in the winter polar region where the water vapor has frozen out of the atmosphere.
The images show ozone lasting into spring, indicating that global winds are inhibiting the spread of water vapor from the rest of the planet into winter polar regions.
Wave patterns in the images, revealed by UV absorption from ozone concentrations, are critical to understanding the wind patterns, giving scientists an additional means to study the chemistry and global circulation of the atmosphere.
These images show rapid cloud formation on Mars on July 9-10, 2016. Time progresses from upper left to lower right with 2.2 hours spacing. The left part of the planet is in morning and the right side in afternoon. Mars’ prominent volcanoes, topped with white clouds, can be seen moving across the disk. Mars’ tallest volcano, Olympus Mons, appears as a prominent dark region near the top of the images, with a small white cloud at the summit that grows during the day. Olympus Mons appears dark because the volcano rises up above much of the hazy atmosphere which makes the rest of the planet appear lighter. Three more volcanoes appear in a diagonal row, with their cloud cover merging to span up to a thousand miles by the end of the day. Image credit: NASA / MAVEN / University of Colorado.
MAVEN observations also show afternoon cloud formation over the four giant volcanoes on Mars, much as clouds form over mountain ranges on Earth.
IUVS images of cloud formation are among the best ever taken showing the development of clouds throughout the day.
Clouds are a key to understanding a planet’s energy balance and water vapor inventory, so these observations will be valuable in understanding the daily and seasonal behavior of the atmosphere.
Dr. Schneider and co-authors will present the findings tomorrow at the joint 48th annual meeting of the Division for Planetary Sciences of the American Astronomical Society and 11th annual European Planetary Science Congress in Pasadena, California.
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Nicholas M. Schneider et al. 2016. Science highlights from MAVEN/IUVS after two years in Mars orbit. DPS48/EPSC11, abstract #303.01
