LHS 1140 b is currently one of the most exciting planets in Lisa Kaltenegger’s research. Located approximately 48.8 light-years away in the constellation Cetus, it is a massive “Super-Earth” that is a prime candidate for being a “Water World.”
Key Physical Characteristics
- Planet Type: Terrestrial (rocky) Super-Earth.
- Mass: It is a heavy-weight, about 5.6 times the mass of Earth.
- Orbit: It orbits its small red dwarf star every 24.7 Earth days.
- Size: It is about 1.7 times the radius of Earth.
Habitability & Environment
In Kaltenegger’s study, LHS 1140 b is a top-priority target because it appears to be even more stable than the TRAPPIST-1 planets:
- Energy Intake: It receives about 43% of the starlight that Earth gets from the Sun. This puts it in a cool but temperate range.
- The “Water World” Theory: Recent density measurements suggest it is not just dry rock. It likely contains a massive amount of water—potentially 10% to 20% of its total mass. This could mean a global ocean hundreds of kilometers deep.
- Atmosphere: There is strong evidence that it may have a thick, nitrogen-dominated atmosphere similar to Earth’s, which would be excellent for protecting life.
Scientific Significance
- Quiet Star Advantage: Its host star is much “quieter” (less active) than many other red dwarfs. This means LHS 1140 b has likely kept its atmosphere and water for billions of years without being stripped away by radiation.
- Ocean Potential: While it is likely tidally locked, its thick atmosphere and deep ocean could allow for a massive liquid ocean area facing the star, even if the rest of the planet is covered in ice.
- Observational Priority: It is a favorite for current large telescopes to search for oxygen and other signs of life because its atmosphere is thought to be very stable and easy to “see” through.
