Science News

In a study published in Nature, scientists using the James Webb Space Telescope (JWST) have found strong evidence of an atmosphere around 55 Cancri e, a rocky exoplanet often described as a “hell planet” due to its extreme conditions. This discovery marks a significant step in exoplanetary science, providing the best proof yet of an atmosphere around a rocky world beyond our solar system.

The Nature of 55 Cancri e
55 Cancri e is a super-Earth, roughly twice the diameter of Earth, located 41 light-years away. It orbits its star, 55 Cancri, at just 4% of the distance between Mercury and the Sun. The planet’s proximity to its star creates surface temperatures high enough to melt iron, likely forming a vast ocean of molten magma. Since its discovery in 2004, scientists have puzzled over various aspects of 55 Cancri e, particularly the nature of its atmosphere.

Unraveling the Atmospheric Mystery
Early observations raised doubts about the possibility of an atmosphere on 55 Cancri e, given its high temperatures and intense stellar radiation. However, recent data from JWST’s mid-infrared instrument (MIRI) and near-infrared camera (NIRCam) suggest otherwise. MIRI measurements revealed that the planet’s daytime temperature is around 2,800 degrees Fahrenheit (1,500 degrees Celsius), significantly lower than the 4,000 degrees Fahrenheit (2,200 degrees Celsius) expected if the planet lacked an atmosphere. This temperature difference implies that atmospheric currents might be redistributing heat from the day side to the night side.

Further analysis using NIRCam identified signs of carbon dioxide or carbon monoxide gas in the planet’s atmosphere. Researchers believe this “secondary atmosphere” is not primordial but continuously replenished by gases bubbling out from the planet’s molten interior. Such a mechanism would allow the atmosphere to persist despite the harsh conditions.

Implications and Future Research
The presence of an atmosphere on 55 Cancri e opens new possibilities for studying the interactions between rocky planet surfaces, interiors, and atmospheres. Although 55 Cancri e is far too hot to support life, understanding its atmospheric dynamics could provide insights into the early conditions of Earth-like planets and the potential for habitability elsewhere in the universe.

Dr. Renyu Hu of NASA’s Jet Propulsion Laboratory, the study’s lead author, emphasizes that JWST is pushing the boundaries of exoplanet characterization, enabling scientists to explore rocky planets in greater detail. Co-author Diana Dragomir from the University of New Mexico, who has studied 55 Cancri e for over a decade, expressed her excitement about the findings, noting that they finally provide some long-awaited answers about this enigmatic world.

Looking Ahead
As researchers continue to analyze JWST data, additional secondary eclipse observations of 55 Cancri e are underway, promising to shed more light on this “hell planet” and its intriguing atmosphere. The ongoing efforts underscore the importance of advanced space telescopes in expanding our understanding of distant worlds and their potential to inform us about the nature of planets closer to home.

Sources:

James Webb telescope detects 1-of-a-kind atmosphere around ‘Hell Planet’ in distant star system
https://www.livescience.com/space/exoplanets/james-webb-telescope-detects-1-of-a-kind-atmosphere-around-hell-planet-in-distant-star-system

NASA’s Webb Hints at Possible Atmosphere Surrounding Rocky Exoplanet
https://science.nasa.gov/missions/webb/nasas-webb-hints-at-possible-atmosphere-surrounding-rocky-exoplanet/