K2-18b

K2-18b Latest News

In 2025, scientists detected the presence of either dimethyl sulphide (DMS) or dimethyl disulphide (DMDS) in the atmosphere of K2-18b.

What is K2-18b?

• K2-18b is an exoplanet (a planet located outside our solar system) situated 124 light-years away from Earth in the constellation Leo, orbiting a star called K2-18.
• It was discovered in 2015 by the Kepler Space Telescope.
• K2-18b is 5.2 times wider and around 9 times more massive than Earth, suggesting it may possess a hydrogen-rich atmosphere.
• The planet receives a similar level of stellar radiation from its star as Earth does from the Sun, hinting at the possibility of habitable surface conditions.

Atmospheric Discoveries

• In 2019, the Hubble Space Telescope detected water vapour in the atmosphere of K2-18b.
• Later, the James Webb Space Telescope (JWST) found the presence of carbon dioxide (CO₂) and methane (CH₄).
• The absence of ammonia along with CO₂ and CH₄ in a hydrogen-rich atmosphere is significant because it may indicate the possible presence of a liquid water ocean.

About Dimethyl Sulphide (DMS)

• DMS is considered a potential biomarker because, on Earth, it is mostly produced by phytoplankton in the oceans.
• DMS is formed when phytoplankton die and enzymes break down dimethylsulphoniopropionate.
• It is also released when soil bacteria decompose plant matter and in trace amounts during volcanic eruptions.
• A 2015 study found that 76% of soil bacteria on Earth contain a gene that produces DMS, reinforcing its biological origin.

K2-18b FAQs

Q1: What is K2-18b?
Ans: K2-18b is an exoplanet located about 120 light-years away from Earth in the Leo constellation, discovered by NASA's Kepler Space Telescope.

Q2: Why is K2-18b significant?
Ans: K2-18b lies in the habitable zone of its star and is one of the first exoplanets where water vapour was detected in its atmosphere, raising the possibility of supporting life.

Q3: What type of planet is K2-18b?
Ans: K2-18b is classified as a "super-Earth" or "mini-Neptune", meaning it is larger than Earth but smaller than Uranus or Neptune.

Source: TH