This remarkable image of Uranus, taken at 3.1 mm with the Atacama Large Millimeter/submillimeter Array (ALMA), reveals thermal emission from the dust that makes up Uranus’s narrow ring system (Uranus itself is masked because it’s so bright compared to the rings). We know that Uranus’s rings are made up of centimeter- to meter-sized particles, but little is known about the composition, mass, or the detailed size distribution of these particles or the amount dust in between them. In a new study led by Edward Molter (University of California, Berkeley), a team of scientists presents ALMA and Very Large Telescope observations of the rings’ thermal emission for the first time. These observations indicate that Uranus’s epsilon ring — the primary ring — is devoid of dust. This stands in stark contrast to the rings around Saturn or Jupiter, for instance, which contain lots of micrometer-sized dust — raising the question of why Uranus’s epsilon ring is so unusual! For more information, check out the article below.

Citation

“Thermal Emission from the Uranian Ring System,” Edward M. Molter et al 2019 AJ 158 47. doi:10.3847/1538-3881/ab258c