The first super-Earths ever discovered have been emitting strange signals for nearly two decades, and scientists may have finally discovered why.
A new study suggests that volcanoes on this hellish world periodically open up and release hot gas that forms an atmosphere, which then burns up and leaves the planet bald again. Testing this theory will involve training the James Webb Space Telescope (JWST) on the strange exoplanet.
Planet 55 Cancri e is a rocky world with a mass about eight times our planet, and it was discovered in 2004 about 40 light-years from Earth.
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The planet is so close to its parent star, less than 2% of the distance between Earth and the Sun, that it orbits completely in just 17 hours. This creates some rather extreme conditions on the planet that defy explanation.
Perhaps the most puzzling aspect of this planet, as pointed out in… Paper accepted in September To the Astrophysical Journal Letters, is the nature of its transit signal. This is the light visible from Earth when 55 Cancri e crosses in front of its parent star, creating a small eclipse, and the light is visible when the planet passes behind its star.
Sometimes, when 55 Cancri e passes behind its star, no visible light comes from the planet itself, while other times the planet emits a strong visible light signal. In infrared light, there is always a signal, although this signal varies in strength.
Observations of infrared light using the Spitzer Space Telescope indicated that the day side of the planet experienced exceptionally scorching temperatures of more than 4,400 degrees Fahrenheit (2,427 degrees Celsius), while the night side was cooler, but still hellish, with temperatures reaching The temperature is about 2060 Fahrenheit. (1127 c).
In the new study, the authors hypothesize that the planet’s proximity to its star causes it to release gases, meaning giant volcanoes and thermal vents open up, spewing hot, carbon-rich elements into the atmosphere. But the planet cannot retain this atmosphere for long due to the intense heat, and this gas eventually volatilizes, leaving the planet empty until it starts outgassing again.
Unlike most planets, 55 Cancri e’s atmosphere is unstable. The outgassing process attempts to increase the volume of the atmosphere, while the intense radiation and solar winds from the star blow it away. But these two processes are not balanced, leading to the situation in which a planet sometimes has an atmosphere, and sometimes does not.
Researchers believe that this imbalance in the planet’s atmosphere could explain the strange transit signals. When a planet is in its atmosphere-free “bald” phase, no visible light comes from the planet’s atmosphere, because there isn’t one, but the planet’s hot surface still emits infrared light. As the atmosphere swells, both visible light and all radiation coming from the surface appear in the transit signal.
Although this is just a hypothesis, the James Webb Space Telescope offers a way to test it. By measuring the pressure and temperature of a planet’s atmosphere, scientists can determine whether or not the atmosphere has always been present.
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