Researchers using NASA’s James Webb Space Telescope have made a groundbreaking discovery regarding the atmospheric gases surrounding 55 Cancri e, a hot rocky exoplanet located 41 light-years away from Earth. This discovery marks the most substantial evidence to date of the existence of a rocky planet atmosphere outside our solar system. Renyu Hu from NASA’s Jet Propulsion Laboratory in California led the research team and published the findings in Nature, emphasizing that Webb’s capabilities are revolutionizing the study of exoplanets.
55 Cancri e, also known as Janssen, is a super-Earth orbiting a Sun-like star in the constellation Cancer, with a diameter almost twice that of Earth and a density slightly greater. Despite being classified as a rocky planet, its proximity to its star results in extreme conditions, causing its surface to likely be molten. Observations suggest that the planet may be tidally locked, with one side facing the star at all times while the other remains in perpetual darkness, presenting unique challenges for researchers studying its atmosphere.
While previous studies using NASA’s Spitzer Space Telescope hinted at the presence of a significant atmosphere rich in volatiles such as oxygen, nitrogen, and carbon dioxide, the true nature of 55 Cancri e’s atmosphere remained uncertain. Webb’s sophisticated instruments allowed researchers to measure infrared light emitted by the planet and differentiate between different atmospheric compositions. The data indicated a relatively low temperature on the planet’s surface, suggesting that energy is being distributed across the planet, likely due to the presence of a volatile-rich atmosphere.
The study utilized a method called secondary eclipse spectroscopy to analyze changes in light from the system as the planet orbits its star, enabling researchers to make inferences about the planet’s atmospheric composition. Patterns observed in the data were consistent with the presence of a volatile-rich atmosphere containing carbon monoxide or dioxide. These findings confirmed long-standing hypotheses regarding the atmospheric conditions of 55 Cancri e and brought new insights into the behavior of atmospheres surrounding rocky exoplanets.
The team’s research suggests that the gases enveloping 55 Cancri e are likely originating from its interior and continuously replenished by the planet’s molten magma ocean. While the planet is too hot to support life, it serves as a valuable target for studying the interactions between atmospheres, surfaces, and interiors of rocky planets. These findings could provide crucial insights into the early conditions of planets like Earth, Venus, and Mars that are believed to have had magma oceans in the past, shedding light on the development of habitable planets.
Through their observations and analysis of 55 Cancri e’s atmosphere, researchers hope to gain a better understanding of the conditions that allow rocky planets to sustain gas-rich atmospheres, a key element in the search for habitable worlds. This research, conducted as part of Webb’s General Observers Program, highlights the telescope’s potential to revolutionize the field of exoplanet research and pave the way for future discoveries regarding planetary atmospheres outside our solar system. Ongoing studies are focused on further analyzing secondary eclipse observations of 55 Cancri e to deepen our understanding of this fascinating exoplanet.
