Context: Astronomers have for the first time discovered water in the atmosphere of an exoplanet with Earth-like temperatures that could support life as we know it. K2-18b is now the only planet orbiting a star outside the Solar System known to have both water and temperatures that could be potentially habitable.
Prelims: Current events of national and international importance- Science & Technology.
- K2-18b, also known as EPIC 201912552 b, is an exoplanet orbiting the red dwarf star K2-18, located 124 light-years away from Earth.
- The planet, initially discovered through the Kepler Space Observatory, was later determined to be about eight times the mass of Earth with a 33-day orbit within the star's habitable zone.
- In 2019, two independent research studies, corroborating data from Kepler, the Spitzer Space Telescope, and the Hubble Space Telescope, concluded that there are significant amounts of water in its atmosphere, the first such discovery for a planet within a star's habitable zone (Goldilocks zone).
- The discovery of K2-18b was made in 2015 as part of observations of the star K2-18, a red dwarf star, about 124 light-years from Earth. The relatively low brightness of K2-18 would make it easier to observe K2-18b's atmosphere in future observations from both orbiting and ground-based observatories.
- In 2017, data from the Spitzer Space Telescope confirmed that K2-18b orbits in the habitable zone around K2-18 with a relatively short 33-day period, which would allow for observations through multiple solar cycles and improving the statistical confidence in data collected. These conditions led to significant interest in the continued observation of K2-18b through future observation programs.
- Computer models of the planet’s atmospheric signature also suggest that it contains significant amounts of hydrogen. But how much gas it has remains a mystery.
- K2-18b, which is eight times the mass of Earth, is now the only planet orbiting a star outside the Solar System, or ‘exoplanet’, known to have both water and temperatures that could be potentially habitable, according to the study published in the journal Nature Astronomy.
The Goldilocks Zone refers to the habitable zone around a star where the temperature is just right – not too hot and not too cold – for liquid water to exist on a planet.