K2-288Bb
Physical characteristics | |
---|---|
Mean radius | 1.90 (±0.3)[2] R🜨 |
Temperature | 226.36 (±22.3) K (−46.79 °C; −52.22 °F)[2] |
K2-288Bb (previously designated EPIC 210693462 b) is a
K2-288Bb is likely to be in the habitable zone of its host star, and thus may be capable on supporting life, though the planet's composition is unknown.
Discovery
K2-288 was observed by the
Characteristics
Mass, radius, and temperature
K2-288Bb is unusual for having a radius not commonly seen among most exoplanets. At 1.90 R🜨, it falls within the so-called
Orbit and rotation
K2-288Bb has a close orbit around the second, smaller star of the binary system. It orbits every 31.393 days at a distance of about 0.164 AU. For comparison, the Earth's Solar System's innermost planet, Mercury, orbits every 88 days at 0.38 AU. However, due to the small size of the host star, K2-288Bb is well within the habitable zone. In the unlikely possibility that the planet orbits the primary, it would have a semi-major axis of 0.231 AU and still reside in the habitable zone.[2] K2-288Bb is probably tidally locked regardless of which star it orbits; one side of the planet would permanently face the host, while the other side would be always facing away.
Host stars
K2-288Bb is within a binary system of two red dwarfs. The primary, K2-288A, is 52% the mass and 45% the radius of the Sun, while the secondary, K2-288B, is 33% the mass and 32% the radius. They are both much cooler and dimmer than the Sun, with temperatures of 3584 K and 3341 K, and are 0.03236 and 0.01175 times as luminous as the Sun, which has a temperature of 5772 K. Both stars are also rather metal-poor, with metallicities of -0.29 dex [Fe/H] for the primary, and -0.21 dex [Fe/H] for the secondary.[2] In comparison, the Sun has a metallicity of 0.00 dex [Fe/H]. K2-288A and K2-288B orbit each other at a distance of about 55 AU, around six times the distance from Saturn to the Sun.[2]
Potential habitability
It is unknown if K2-288Bb is capable of supporting life. On one hand, it is likely well within the habitable zone of its star, with a temperate equilibrium temperature of about 226 K. However, because of its radius within the Fulton gap, there is significant uncertainty in its composition. K2-288Bb could be a potentially habitable rocky or water-rich world, but it might also be a hostile gas planet.[4]
See also
References
- ^ a b c d e Hawkes, Alison; Cofield, Calia; Reddy, Francis (7 January 2019). "Citizen Scientists Find New World with NASA Telescope". NASA. Retrieved 8 January 2019.
- ^ hdl:1721.1/121222.
- ^ Mack, Eric (9 January 2019). "NASA's Kepler helps amateurs spot unusual new planet in 'Goldilocks zone'". CNET. Retrieved 9 January 2019.
- ^ a b c d Feinstein, Adina (7 January 2019). "Exoplanet Explorers Discoveries - A Small Planet In The Habitable Zone". Zooniverse.org. Retrieved 8 January 2019.