K2-18 b
Sign in to saveK2-18b, also known as EPIC 201912552 b, is an exoplanet orbiting the red dwarf K2-18, located away from Earth. The planet is a sub-Neptune about 2.6 times the radius of Earth, with a 33-day orbit within the star's habitable zone; it receives approximately a similar amount of light as the Earth receives from the Sun. Initially discovered with the Kepler space telescope, it was later observed by the James Webb Space Telescope (JWST) in order to study the planet's atmosphere.
Key facts
- Planet.extrasolarplanet
- yes
- Planet.name
- K2-18b
- Planet.image
- File: Exoplanet K2-18 b (Illustration).jpg
- Planet.caption
- Artist's impression of K2-18b (right) orbiting red dwarf K2-18 (left); the small crescent in the middle is K2-18c in planetary phase
- Planet.discovery_site
- Kepler space telescope
- Planet.discovered
- 2015
- Planet.discovery_method
- Transit
- Planet.apsis
- astron
- Planet.period
- <!--
- Planet.arg_peri
- ° <!--
- Planet.semi amplitude
- -->
- Planet.star
- K2-18
via Wikipedia infobox
Exoplanet data
- Host star
- K2-18
- Discovered
- 2015
- Discovered by
- K2
- Orbital period
- 32.94 days
- Radius
- 2.37 × Earth
- Mass
- 8.92 × Earth
- Equilibrium temp
- 284 K
- Distance
- 38.03 pc
via NASA Exoplanet Archive
Article
15 sectionsContents
- Host star
- Physical properties
- Possible ocean
- Atmosphere and climate
- Evolution
- Alternative scenarios
- Models
- Habitability
- Discovery and research history
- Presence or absence of biosignatures
- See also
- Notes
- References
- Sources
- External links
K2-18b, also known as EPIC 201912552 b, is an exoplanet orbiting the red dwarf K2-18, located away from Earth. The planet is a sub-Neptune about 2.6 times the radius of Earth, with a 33-day orbit within the star's habitable zone; it receives approximately a similar amount of light as the Earth receives from the Sun. Initially discovered with the Kepler space telescope, it was later observed by the James Webb Space Telescope (JWST) in order to study the planet's atmosphere.
JWST discovered water vapour, carbon dioxide and methane in its atmosphere. JWST's data has been variously interpreted as indicating a water ocean planet with a hydrogen-rich atmosphere, and a gas-rich mini-Neptune. K2-18b has been studied as a potential habitable world that, temperature aside, more closely resembles an ice giant like Uranus or Neptune than Earth. It is the prototype for hycean planets, planets which have abundant water under a hydrogen envelope.