The gases that cover 55 Cancri e bubble from its interior. The primordial atmosphere has long since disappeared due to the high temperature and intense radiation from the star
New observations by the James Webb Space Telescope have shed light on the enigmatic super-Earth, revealing its possible atmosphere composed of gases such as carbon monoxide or dioxide. This discovery highlights the star's extreme conditions due to its proximity to its star, and its potential to offer insights into the early atmospheres of rocky planets.
atmosphere on a rocky extrasolar planet for the first time
55 Cancri e or Janssen is one of five known planets orbiting a Sun-like star in the constellation Cancer. With a diameter twice that of Earth and a slightly higher density, the star is classified as a super-Earth: larger than Earth, smaller than Neptune, and similar in composition to the rocky planets in our solar system.
Brice-Olivier Demori of the CSH Center for Space and Population Studies of the University of Bern and a member of the NCCR PlanetS is a co-author of the study just published in Nature.
He says: "Jansen is one of the most enigmatic extrasolar planets. Despite vast amounts of observing time achieved over the past decade with a dozen ground-based and space-based facilities, its exact nature remains elusive, until today, when the pieces of the puzzle can finally be assembled thanks to the James Webb Space Telescope (JWST).”
Important discoveries of the CHEOPS space telescope
Demori was invited to the research program by Hu, one of his former colleagues at the Massachusetts Institute of Technology (MIT). Demori has been studying Jansen since the beginning of his career: "As a postdoctoral fellow at MIT, I led the discovery of its first transit across the parent planet, and in 2016 my team published the first map of a rocky extrasolar planet, which would be Jansen."
A bubbling lava ocean
The group thinks that the gases covering 55 Cancri e are bubbling up from its interior. The primordial atmosphere has long since disappeared due to the high temperature and intense radiation from the star. This would be a secondary atmosphere that is constantly renewed by the lava ocean. Lava is not only crystals and molten rock, it has many dissolved gases as well.
While Jansen is too hot to be habitable, it may provide a unique window into the study of the interactions between atmospheres, surfaces and interiors of rocky planets, and perhaps provide insights into early Earth, Venus and Mars, which are thought to have been covered in a lava ocean long ago. "Ultimately, we want to understand what conditions allow a rocky planet to have a gas-rich atmosphere: the key ingredient for a habitable planet," Hu said.
More on the subject on the science website
