Question: Astronomers recently discovered water in the atmosphere of K2-18b, a planet orbiting a red dwarf star K2-18b.This star is located in-
(a) Constellation Leo
(b) Constellation Libra
(c) Constellation Sagittarius
(d) Constellation Aries
Answer: (a)
Related facts:
- Astronomers have for the first time discovered an Exoplanet with presence of water in its atmosphere.
- Details regarding the discovery of such planet were published in September 2019 in the scientific journal Nature Astronomy.
- Its atmosphere was studied by astronomers at the University College London (UCL) and ultimately the results are published in the journal.
- This planet is orbiting a red dwarf star K2-18 located about 110 light years from Earth in the constellation Leo.
- The new planet is just over twice in the size and eight times the mass of the Earth.
- It is a planet in the category known as a “super Earth” – and has a temperature cool enough to have liquid water, between zero and 40C.
- The lead scientist, Prof Giovanna Tinetti of University College London (UCL), described the discovery as mind blowing.
- The exoplanet also lies within the habitable zone of its star, which means it will have the right temperature for liquid water to exist on the surface of the planet and potentially support life.
Background of the Discovery of K2-18b:
- The planet was first discovered by NASA’s Kepler spacecraft in 2015.
- The K2-18b exoplanet completes one orbit around its star every 33 days.
- The super-Earth is much closer to its star than the Earth is to the sun. However, the red dwarf star is much cooler than the Sun.
- Researchers therefore based on the calculations speculated that the exoplanet could have a temperature, similar to that of the Earth.
- It is also emphasised on the point that the temperature range upon the planet, however, could include temperatures much colder and warmer than Earth.
- Conclusion is that though the actual conditions on the surface of the planet are not known, the red dwarf star it orbits is quite active.
- This means that the planet will be exposed to ultraviolet radiation.
- However, the study reveals that K2-18b receives about the same amount of radiation from its star as the Earth does from the sun.
Links:
https://www.thehindu.com/sci-tech/science/water-found-for-first-time-on-potentially-habitable-planet/article29397908.ece
https://www.nationalgeographic.com/science/2019/09/first-water-found-in-habitable-exoplanets-atmosphere-hubble-kepler-k2-18b/
https://www.nasa.gov/feature/goddard/2019/nasa-s-hubble-finds-water-vapor-on-habitable-zone-exoplanet-for-1st-time