K2-187b
K2-187b, previously designated EPIC 212157262.04, is a confirmed exoplanet, likely rocky, closely orbiting the Sun-like star K2-187 in the constellation Cancer. Discovered by the Kepler space telescope during its K2 “Second Light” mission, K2-187b is nearly 40% larger than Earth and orbits every 0.77 days (~18 hours), making it one of the shortest-period planets yet found. It is the first of four planets around K2-187 validated in February 2018.[1] In terms of radius, orbit, and temperature, it is very similar to the planets Kepler-10b and 55 Cancri e.
Characteristics[edit]
Mass, radius, and temperature[edit]
K2-187b is a Super-Earth, meaning that it has a radius or mass greater than that of Earth but smaller than that of Uranus or Neptune. It has a radius of 1.38 R⊕, but has an unknown mass. Because it was discovered with the transit method, only its radius can be determined. However, its small size indicates that K2-187b is likely rocky. [2]
The planet is extremely hot due to its proximity to its host star. It has an equilibrium temperature of about 1,788 K (1,515 °C; 2,759 °F), as hot as a blast furnace and close to the melting point of iron.[3]
Orbit[edit]
K2-187b orbits extremely close to its host star. One orbit takes just 0.774 days, or about 18 hours, to complete. K2-187b orbits at a distance of only 0.0163 AU from its host star, or about 1.6% the distance between Earth and the Sun. For comparison, the closest planet in our Solar System, Mercury, takes 88 days to orbit at a distance of about 0.38 AU. The orbital inclination of K2-187b is about 81 degrees to our line of sight, which is several degrees off from the inclinations of the other three planets, which are all around 88-90 degrees.[4] It is near a 4:1 resonance with K2-187c.
Host star[edit]
K2-187b orbits the Sun-like G-type star K2-187. It is not much smaller and cooler than the Sun, at 0.895 R☉ and 0.967 M☉ with a temperature of 5477 K. Its age is unknown. For comparison, the Sun has a temperature of 5778 K and is 4.5 billion years old. K2-187 has a much higher quantity of heavy elements than the Sun, with a metallicity of +0.26 Fe/H.[5]
See also[edit]
References[edit]
- ↑ http://outer.space.dtu.dk/awm/images/validationpaper.pdf
- ↑ http://outer.space.dtu.dk/awm/images/validationpaper.pdf
- ↑ http://phl.upr.edu/projects/habitable-exoplanets-catalog/calculators
- ↑ http://outer.space.dtu.dk/awm/images/validationpaper.pdf
- ↑ http://outer.space.dtu.dk/awm/images/validationpaper.pdf
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