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Credit: ALMA (ESO / NAOJ / NRAO), S. Trumbo et al. NRAO / AUI NSF, S. Dagnello; NASA / Hubble
Jupiter's iced Europa moon has a chaotic fractured and cracked surface, suggesting a long history of geological activity.
A new series of four Europa images taken with Atacama's Large Atacama Multimeter / Multimeter Network (ALMA) helped astronomers create the first global thermal map of this cold Jupiter satellite. The new images have a resolution of about 200 km, sufficient to study the relationship between thermal surface variations and the main geological features of the moon.
The researchers compared ALMA's new ALMA observations made by ALMA with a thermal model based on observations of the Galileo spacecraft. This comparison allowed them to analyze the temperature changes in the data and to build the world's very first global map of thermal features of Europa. The new data also revealed an enigmatic cold spot in the northern hemisphere of Europa.
"These ALMA images are really interesting because they provide the world's first thermal emission map of Europe," said Samantha Trumbo, a scientist in planetary science at the California Institute of Technology and senior author of an article published in the Astronomical Journal. "Europa being an oceanic world with potential geological activity, its surface temperatures are of great interest as they may limit the location and extent of such activities."
Series of 4 images of the surface of Europe taken with ALMA, allowing astronomers to create the first global thermal map of Jupiter's frozen moon. Credit: ALMA (ESO / NAOJ / NRAO), S. Trumbo et al.
Evidence strongly suggests that under its thin layer of ice, Europa has an ocean of brackish water in contact with a rocky core. Europa also has a relatively young surface, about 20 to 180 million years old, which indicates that unidentified thermal or geological processes are at work.
Unlike optical telescopes, which can only detect sunlight reflected by planetary bodies, radio and millimeter-wave telescopes like ALMA detect the natural "glow" of heat emitted by the coldest objects in our solar system, including comets. , asteroids and moons. At its warmest, the surface temperature of the Europa never exceeds less than 160 degrees Celsius (minus 260 degrees Fahrenheit).
"The study of Europa's thermal properties provides a unique way to understand its surface," said Bryan Butler, astronomer at the National Radio Astronomy Observatory in Socorro, New Mexico, and co-author of document.
Explore further:
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More information:
Samantha K. Trumbo et al. ALMA Thermal Observations of Europa, The astronomical journal (2018). DOI: 10.3847 / 1538-3881 / aada87
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