Could this nearby exoplanet be the first known ocean world beyond our Solar System?
New observations from the James Webb Space Telescope confirm LHS 1140 b as a rocky super-Earth with significant water, making it a prime candidate for potential liquid water and life beyond our Solar System.
LHS 1140 b, discovered in 2017, lies 48 light years away in the habitable 'Goldilocks zone,' an area where conditions are just right for liquid water to exist. Initially thought to be a mini-Neptune, recent observations from the James Webb Space Telescope confirmed it as a rocky super-Earth, 1.7 times the size of Earth with 5.6 times its mass. The planet's density indicates a substantial amount of water, potentially 10 to 20 percent of its mass, compared to Earth's oceans, which account for only 0.02 percent of our planet's mass.
This groundbreaking discovery, detailed in a study published recently in The Astrophysical Journal Letters, marks LHS 1140 b as one of the most promising candidates for finding liquid water and, by extension, life outside our Solar System.
Potential for Liquid Water and Atmosphere
LHS 1140 b's significant water content raises exciting possibilities. The key question is whether this water is liquid, which depends on the planet's atmosphere. While direct evidence of an atmosphere is lacking, several indicators suggest its presence.
The exoplanet is gently warmed by its red dwarf star, potentially creating Earth-like surface temperatures suitable for liquid water. Gases like carbon dioxide will be crucial in determining if the surface is icy or watery. According to Turbet, the planet's density suggests it contains large quantities of water, reinforcing the potential for habitability.
Lead study author Charles Cadieux highlights that LHS 1140 b could be the best candidate for indirectly confirming liquid water on an 'alien world'. Modeling suggests two scenarios: a mostly icy surface with a vast liquid ocean where the planet receives the most heat, or liquid water beneath a thick ice shell, similar to moons of Jupiter and Saturn. Signs of nitrogen further support a habitable environment.
Research and Future Exploration
The discovery of LHS 1140 b as a potential ocean world opens new research avenues. Scientists seek more observation time with the James Webb Telescope to confirm the planet's atmosphere and identify gases like carbon dioxide. This process could take several years but is crucial for understanding LHS 1140 b's habitability.
Cadieux and his team estimate it will take at least a year to confirm the atmosphere and two to three more years to detect carbon dioxide. These findings could greatly impact our understanding of life beyond Earth.
The potential discovery of an ocean world so close to our Solar System is a major milestone. LHS 1140 b offers one of the best opportunities to study a habitable environment outside our planetary system, providing vital clues about the conditions necessary for life.
News reference:
Celerier, P. "Nearby exoplanet could be first known ocean world: Webb telescope"https://phys.org/news/2024-07-nearby-exoplanet-ocean-world-webb.html