41 light-years away, planet 55 Cancri e orbits a Sun-like star, 55 Cancri A. Researchers from the Leiden Observatory and the Netherlands Institute for Space Research (SRON) have discovered an atmosphere at 55 Cancri e with James. Webb Space Telescope – also known as Janssen, after the Dutch inventor of the telescope.
55 Kankri H: Earth without the crust
“So far, we have only detected atmospheres outside our solar system on very large gas giants, exoplanets similar to Saturn and Jupiter,” says researcher Christian van Bossem of the Leiden Observatory. “It is remarkable that we are now observing such an atmosphere on a smaller, rocky planet.”
Janssen is called a “super-Earth” because it is about twice the size of Earth (and eight times heavier). In composition, the planet is likely similar to other rocky planets in our solar system, but with a different type of surface.
“You can see Janssen as Earth, but without the crust,” says Van Bochem. “It’s so warm that the planet’s diurnal surface has likely melted.” Janssen is 25 times as close to its star as Mercury is to the Sun. Due to this small distance, the same side always faces the star, just as the Moon does to the Earth, giving it a permanent day-and-night aspect.
Atmosphere discovered by James Webb
Thanks to the planet’s extremely high temperature, it can be detected by the infrared instruments of the James Webb Telescope, which not only take very beautiful images. The infrared light received comes from the hotter day side, where the temperature without an atmosphere should be about 2,200 degrees Celsius.
But measurements show that the temperature is “only” 1,540 degrees Celsius. The heat is likely to be transferred to the cooler night side, indicating the presence of an atmosphere. “Without an atmosphere, it would be very difficult for that heat energy to move,” says van Bochem.
Dutch organizations
The composition of the atmosphere has also been estimated, which will consist partly of carbon monoxide and carbon dioxide. According to Van Buchem, more research is needed to better map the atmosphere; in the future, other telescopes will be directed towards Janssen, which can measure other wavelengths.
The discoveries at Janssen are due in part to the James Webb Telescope’s new, highly sensitive infrared instruments: NIRCam and MIRI. Dutch organizations played an important role in the development of MIRI. The equipment was installed during the construction of the James Webb Telescope.
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