K2-18b: Potentially Habitable Planet | 13 Sep 2019

Scientists have found signatures of water vapour in the atmosphere of K2-18b.

• K2-18b is the only planet orbiting a star outside the Solar System (exoplanet) that is known to have both water and temperatures that could support life.
• However, K2-18b’s size and surface gravity are much larger than Earth’s. Its radiation environment, too, maybe hostile.
• K2-18b orbits the cool dwarf star K2-18, which is about 110 light-years from Earth in the Leo constellation.
• It is eight times the mass of Earth. It was discovered in 2015 by NASA’s Kepler spacecraft.
• It resides in a habitable zone or Goldilocks zone, the area around a star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets.
  
  • The size of the habitable zone clearly depends on the luminosity of the star, which determines the equilibrium temperature of the planet.
  • For low-mass, cool stars, the region is closer to the star, and for higher mass, hotter stars, the region is more distant from the star.

Source: TH