- Researchers used two most advanced ground-based telescopes to measure the temperature of the rings of Uranus.
- Uranus ring system has a temperature of -196°C (77 Kelvin), just about the boiling point of liquid nitrogen.
Typically, Saturn is the only planet that is pictured with rings. Although Jupiter, Neptune, and Uranus have equally fascinating ring systems, they can only be observed with powerful telescopes.
Uranus has 13 rings, most of which are opaque and only a few kilometers wide. Since they reflect very little light in the near infrared and optical wavelength, it’s very hard to study them. In fact, the rings are so dim that astronomers were not able to observe it for almost two centuries after the planet’s discovery.
Recently, a research team at the University of California, Berkeley, measured the temperature of the Uranus ring system by analyzing the images captured by two advanced telescopes – Very Large Telescope (VLT) and Atacama Large Millimeter/submillimeter Array (ALMA).
Unlike Saturn’s main ring, Uranus’ rings are extremely dark and narrow. The broadest one (the epsilon ring) could be anywhere between 12 and 62 miles wide, whereas rings of Saturn are tens of thousands of miles wide.
In 1986, images captured by Voyager 2 spacecraft showed that Uranus’ main rings have a very small quantity of dust-sized particles. However, it wasn’t able to record the rings’ temperature.
The new observations show that the Uranus ring system has a temperature of -196°C (77 Kelvin), just about the boiling point of liquid nitrogen. The densest and brightest ring — known as epsilon ring — has different characteristics than the rings of Saturn, Jupiter, and Neptune.
Reference: arXiv:1905.12566 | UC Berkeley
Most of the Saturn’s icy rings are bright, wide, and have various particles sizes ranging from tens of meters to micron-sized dust. The main rings of Uranus, on the other hand, consist of larger (golf ball-sized) rocks. Neptune’s rings are mostly dust and Jupiter’s rings are composed of tiny, micron-sized particles.
Rings of Uranus
Researchers don’t know much about the composition of Uranus’ rings and how these rings came into existence in the first place. They could be remnants of moons crashed into one another, parts of asteroids captured by the Uranus’ gravity, or debris left at the time of planet’s formation 4.6 billion years ago. This study will help scientists answer these questions.
Telescopes Reveal Uranus’ Ring Temperature For the Time
ALMA is the most expensive ground-based telescope designed to observe electromagnetic radiation at millimeter and submillimeter wavelengths, while VLT operates at optical and infrared wavelengths and can detect objects about 4 billion times fainter than can be detected with the naked eye.
Both telescopes provided astonishing details that were consistent with visible and near-infrared reflected light observations, confirming the hypothesis that micron-sized dust isn’t present in the Uranus ring system.
Read: Uranus’ Atmosphere Smells Like Rotten Egg
In the coming years, researchers will try to take observations at higher spatial resolution via ALMA to resolve the inner main ring separately and quantify the tiny dust particles if present.
Moreover, the James Webb Space Telescope (planned to be launched in 2021) will provide better spectroscopic constraints on the Uranus’ rings.
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