(ORDO NEWS) — Ever since we first noticed it in the mid-1970s, scientists have been puzzled by Saturn’s Lyman-alpha (Lyα) bulge: a particularly bright band of ultraviolet light emitted by hydrogen atoms during a certain type of electronic transition.
Now there is an explanation. A new study reveals how the rain of ice particles from Saturn’s rings plays a role in warming the planet’s upper atmosphere through further chemical reactions that we still don’t fully understand.
According to NASA, this is the first time we have observed this phenomenon in the solar system.
The research team believes the new information could be used to search for other planets with rings similar to those of Saturn.
“Everything is controlled by ring particles cascading into the atmosphere at certain latitudes,” says astronomer Lotfi Behn. -Jaffel, from the Institute of Astrophysics in Paris, France.
“They modify the upper atmosphere by changing the composition.”
“And then you also have collisional processes with atmospheric gases, which probably heat up the atmosphere at a certain height.”
We already know about ring rain, how the giant rings around Saturn break up into the planet itself; According to experts, the rings could completely disappear in just 100 million years.
What we didn’t know was the interactions of rain with hydrogen.
The researchers studied ultraviolet radiation readings from the Voyager 1, Voyager 2 and Cassini spacecraft, as well as the International Ultraviolet Explorer spacecraft and the Hubble Space Telescope, to obtain consistent Lα radiation readings.
When some of these readings were taken initially, the UV readings were dismissed as noise interference from the probes themselves.
Now, however, researchers have shown that there is indeed a brighter Lα light emission band in the northern hemisphere of the planet.
“When everything was calibrated, we clearly saw that the spectra were the same in all missions,” says Ben-Jaffel.
“This is possible because we have the same reference point, derived from Hubble, for the rate of energy transfer from the atmosphere, measured over decades.”
“It was really a surprise for me. different light distribution data together, and then I realized, wow, it’s the same.”
Saturn’s atmosphere is 75 percent hydrogen and 25 percent helium, with fewer traces of other substances and more wind: up to 1,800 kilometers (1,118 miles) per hour at the equator.
The temperature in the layers of the atmosphere ranges from -130 °C (-202 °F) to about 80 °C (176 °F).
The data collected by various spacecraft spans several years, allowing scientists to study multiple seasons and solar cycles on the planet.
The nature and persistence of ultraviolet light means that raining ice rings is the most likely explanation.
As the researchers note, this is another evidence of variations in exoplanets – for example, Jupiter has a different type. from the bulge of Lyman-alpha (Lyα) to Saturn.
This is all useful information as our telescopes become more powerful and can capture more of the universe around us.
“We’re just at the beginning of this ring characterizing the impact on the planet’s upper atmosphere,” says Ben-Jaffel.
“Ultimately, we want to have a global approach that will give a real characterization of the atmospheres of distant worlds.”
“One of the goals of this study is to see how we can apply it to planets orbiting other planets.” Call it the search for “exo-rings.”
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