Data hints at exoplanet possessing possible liquid ocean surface
Carbon-bearing molecules have been discovered in the atmosphere of the habitable zone exoplanet K2-18 b by an international team of astronomers using data from NASA’s James Webb Space Telescope. These results are consistent with an exoplanet that may contain an ocean-covered surface underneath a hydrogen-rich atmosphere. This discovery provides a fascinating glimpse into a planet unlike anything in our Solar System and raises interesting prospects about potentially habitable worlds elsewhere in the Universe.
The investigation into K2-18 b, which is 8.6 times as massive as Earth, reveals the presence of carbon-bearing molecules, including methane and carbon dioxide. These findings add to recent studies that suggest the exoplanet could be a Hycean exoplanet, one that has the potential to possess a hydrogen-rich atmosphere and a water ocean-covered surface.
This exciting discovery offers new insights into exoplanets and the possibility of life beyond our solar system. The first insights into the atmospheric properties of K2-18 b came from observations with NASA’s Hubble Space Telescope, which prompted further studies that have changed our understanding of the system.
K2-18 b orbits the cool dwarf star K2-18 in the habitable zone and is located 120 light-years from Earth in the constellation Leo. Exoplanets like K2-18 b, with sizes between those of Earth and Neptune, are poorly understood and are the subject of active debate among astronomers.
The suggestion that K2-18 b could be a Hycean exoplanet is intriguing, as some astronomers believe that these worlds are promising environments to search for evidence of life on exoplanets. The abundance of methane and carbon dioxide, along with the shortage of ammonia, supports the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b.
Further observations with NASA’s James Webb Space Telescope, which has an extended wavelength range and unprecedented sensitivity, may confirm the presence of a molecule called dimethyl sulfide (DMS) in the exoplanet’s atmosphere. On Earth, DMS is only produced by life, with the bulk of it emitted from phytoplankton in marine environments.
While K2-18 b lies in the habitable zone and is now known to harbor carbon-bearing molecules, its large size and composition mean that it does not necessarily support life. The planet likely contains a large mantle of high-pressure ice, like Neptune, with a thinner hydrogen-rich atmosphere and a possible ocean surface. Characterizing the atmospheres of exoplanets like K2-18 b is a challenging task due to the glare of their parent stars.
However, the team of astronomers analyzing K2-18 b’s parent star’s light as it passes through the exoplanet’s atmosphere has been able to determine the gases present. This method provides crucial insights into the exoplanet’s atmospheric composition.
The discovery of carbon-bearing molecules in the atmosphere of K2-18 b is a significant step towards understanding exoplanets and their potential for habitability. With future research using Webb’s MIRI spectrograph, the team hopes to validate their findings and gain further insights into the environmental conditions on K2-18 b.
The ultimate goal of this research is to identify life on a habitable exoplanet, which would revolutionize our understanding of our place in the universe. The findings from this investigation are a promising step towards a deeper understanding of Hycean worlds and the search for life beyond Earth.
The James Webb Space Telescope continues to push the boundaries of space exploration, solving mysteries within our solar system and beyond. As an international program led by NASA, in collaboration with ESA and the Canadian Space Agency, Webb is at the forefront of astronomical discoveries and is shedding light on the structures and origins of our universe.