Question

Consider the following statements regarding “K2-18b”

1. It is a potentially ‘habitable’ planet
2. It is the only planet orbiting a star outside the Solar System that is known to have both water and temperatures that can support life.
3. It is eight times the mass of Jupiter.

Which of the statements given above is/are correct?
(a) 1 only
(b) 1 and 2 only
(c) 3 only
(d) 1, 2 and 3

Answer 1

Option B - 1 and 2 Only

■ Explanation :-

• Statement 3 is incorrect :- It is eight times the mass of Earth and not Jupiter.

More Information

■ K2-18b :-

• K2-18b an exoplanet that orbits around a small red dwarf star K2-18, nearly 110 light-years away in the constellation Leo.

• K2-18b was first discovered in 2015 by Nasa’s now retired Kepler space telescope.

• It was found orbiting within the red dwarf star’s habitable zone, making it an ideal candidate to have liquid surface water.

• Having a mass that is eight times greater than Earth’s, K2-18b is also known as Super-Earth exoplanets with masses between those of Earth and Neptune.

• The Kepler satellite mission discovered nearly two-third of all known exoplanets. While the mission indicated that five to 20 per cent of these are located in the habitable zone of their stars.

• Water vapour has been detected on K2-18b a potentially ‘habitable’ planet by Nasa and the European space agency’s Hubble Space Telescope.

• K2-18b could be the only exoplanet known to have both water and temperatures in its atmosphere to sustain liquid water on a řocky surface.

• The new finding offers an ‘unprecedented opportunity’ to gain insight into the composition and climate of habitable-zone planets.

• K2-18b is not ‘Earth 2.0’ as it is significantly heavier and has a different atmospheric composition.

• This study contributes to our understanding of habitable worlds beyond our Solar System and marks a new era in exoplanet research.

What is an Exoplanet ?

• All of the planets in our solar system orbit around the Sun. Planets that orbit around other stars are called exoplanets.

• Exoplanets are very hard to see directly with telescopes. They are hidden by the bright glare of the stars they orbit.

• There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of planets near the star; thus, 85% of the exoplanets detected are inside the tidal locking zone.

• One way to search for exoplanets is to look for “wobbly” stars. A star that has planets doesn’t orbit perfectly around its center. From far away, this off-center orbit makes the star look like its wobbling.

• The most massive planet listed on the NASA Exoplanet Archive is HR 2562 b, about 30 times

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