The illustration shows what exoplanet 55 Cancri e might look like, based on current understanding of the planet.

55 Cancri e is a rocky planet nearly twice the diameter of Earth, orbiting its Sun-like star just 0.015 astronomical units away. Due to its narrow orbit, the planet is extremely hot, with daytime temperatures reaching up to 4,400 degrees Fahrenheit (about 2,400 degrees Celsius). Although previous studies have ruled out a dense atmosphere consisting of hydrogen, carbon dioxide or water, it is possible that the planet has a substantial atmosphere consisting of oxygen or nitrogen, or a very thin atmosphere containing mineral vapors , such as silicon oxide.

The researchers suggest that if the planet is tidally locked, the illuminated surface must be permanently molten. If the planet were not tightly locked, it would experience day-night cycles, with the surface heating and melting during the day, cooling and solidifying at night. The extremely high temperatures of the day will also cause some of the molten rock to evaporate, creating a very thin mineral vapor atmosphere. During the evening, this water vapor condenses and falls as lava rain to the surface, where it solidifies during the night. Spectroscopic observations using Webb’s Near Infrared Camera (NIRCam) and Mid-Range Infrared Instrument (MIRI) will help determine whether the planet has an atmosphere and, if so, what that atmosphere is made of. into what word? Observations will also help determine whether the planet is tidally locked.