About This Image
Illustration showing what exoplanet 55 Cancri e could look like, based on current understanding of the planet.
55 Cancri e is a rocky planet with a diameter almost twice that of Earth orbiting just 0.015 astronomical units from its Sun-like star. Because of its tight orbit, the planet is extremely hot, with dayside temperatures reaching 4,400 degrees Fahrenheit (about 2,400 degrees Celsius).
Although previous studies have ruled out a thick hydrogen, carbon dioxide, or water atmosphere, it is possible that the planet has a substantial atmosphere made of oxygen or nitrogen, or a very thin atmosphere of mineral vapor, such as silicon oxide.
Researchers think that if the planet is tidally locked, the lit surface must be permanently molten. If the planet is not locked, it would experience day-night cycles, with the surface heating up and melting during the day, and cooling and solidifying at night. The extreme heat during the day would also cause some of the molten rock to vaporize, forming a very tenuous mineral vapor atmosphere. In the evening, this vapor would condense and fall as a rain of lava back onto the surface, where it would turn solid overnight.
Spectroscopic observations using Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) will help determine whether or not the planet has an atmosphere, and if so, what that atmosphere is made of. The observations will also help determine whether or not the planet is tidally locked.
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ARTWORK: NASA, ESA, CSA, Dani Player (STScI)
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