Scientists have been puzzled by the enigmatic exoplanet 55 Cancri e ever since its discovery in 2004. Classified as a rocky ‘super-Earth,’ this fiery world orbits its star at a mere 4% of the distance between Mercury and the sun. Its extreme proximity results in surface temperatures hot enough to melt iron, making it a prime candidate for a ‘hell planet’ devoid of any atmosphere.
Intriguingly, new evidence from JWST suggests that 55 Cancri e does indeed possess an atmosphere, albeit an unusual one. Using JWST’s mid-infrared instrument (MIRI), researchers measured surprisingly low thermal emissions from the planet’s day side. This observation hinted at the presence of an atmospheric current transporting heat from the day side to the night side.
Further analysis using the near-infrared camera (NIRCam) instrument revealed the chemical composition of this suspected atmosphere. The team detected the presence of carbon dioxide or carbon monoxide gas swirling around the planet’s molten rock surface.
However, scientists speculate that this gaseous layer is not a remnant from the planet’s formation. Instead, they propose that it is a ‘secondary atmosphere’ continuously replenished by the planet’s interior. This volatile atmosphere would replenish itself even as gases are stripped away by the intense solar winds from its nearby star.
The presence of an atmosphere on 55 Cancri e has significant implications for understanding the evolution and habitability of exoplanets. It demonstrates that even extreme environments can harbor atmospheres and challenges the conventional wisdom about the conditions necessary for atmospheric retention. This discovery opens up exciting new avenues for exploring the diversity and complexity of exoplanetary atmospheres.
