Although Saturn has the mostimpressive system of rings in the solar system, this planet is not the only one that can boast such a distinctive feature. Neptune, Jupiter and Uranus also have rings, but they are less pronounced, and therefore it is very difficult to observe them without a very powerful telescope. During the last study, scientists from the United States and the United Kingdom managed to find out some details about the rings of Uranus. In particular, astronomers were able to measure their temperature for the first time, as reported in an article in the Astronomical Journal.
That Saturn has a ring systemknown for a long time. They were first discovered by Galileo Galilei in 1610. However, the system of the rings of Uranus is a relatively recent discovery. They were first talked about only in 1977, when they opened with the help of the Kuiper Air Observatory. When the Voyager-2 spacecraft flew past Uranus in 1986, he was able to take a closer look at the ring system of this planet.
Uranus Ring System
Today, astronomers emit 10 rings around Uranus,as well as 3 wide dust rings, which from near to far are called 1986U2R / ζ, 6, 5, 4, α, β, η, γ, δ, λ, ε, ν, and μ. According to available data, the radius of the inner ring is about 38 thousand kilometers, and the outer one is almost 100 thousand. By properties, they are significantly different from Saturn's rings: they are significantly darker (only about two percent albedo versus 60 for some Saturn's rings), and all narrow rings except λ consist almost entirely of fairly large bodies from tens of centimeters to several meters in diameter. However, many parameters of the rings remain unclear to scientists. In particular, it is not clear what they consist of, how thick and massive they are.
As part of a new study, scientists from the US andGreat Britain for the first time obtained data on observations of rings in the millimeter and medium infrared ranges, where the maximum thermal luminosity of bodies heated to tens of kelvins is located. The data were collected using the ALMA telescope network (“Atakam's large millimeter-range antenna array”) and the eight-meter VLT telescope (“Very large telescope”).
Features of the rings of Uranus
The researchers found that the temperature of the bodies inthe brightest ring was at the level of 77 kelvins (-196 degrees Celsius), which is quite high and indicates either slow cooling after the planet has entered the shade, or slow rotation. The study also made it possible to confirm that the brightest and densest ring of the planet ε (epsilon) is very different from other known rings found on some planets in the solar system. For example, the system of Saturn's rings is markedly distinguished by the fact that it consists of objects of various sizes, from microscopic dust particles to objects the size of large cobblestones. However, the rings of Uranus seem to consist mainly of relatively large objects.
"We knew that the epsilon ring was somewhat unusualas it does not observe small particles. Some effect pushes them out. We do not know which one yet. But this is an important step in understanding the composition of the rings: whether they consist of one source material or is it different for each individual ring of the planet, ”says co-author Edward Molter of the University of California at Berkeley.
In addition, scientists have found that the rings of Uranus are much darker and thinner than the saturian ones.
"The rings of Uranus in terms of composition differ fromthe main rings of Saturn: in the optical and infrared range their albedo is much lower, they are really dark as coal. They are also extremely thin compared to the Saturnian ones: the width of the most noticeable ring ε varies from 20 to 100 kilometers, while at Saturn the width of rings can reach hundreds of thousands of kilometers, ”adds the researcher.
The team adds that more powerful space telescopes, such as the newest James Webb, will help to find out more details about the Uranus ring system.
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