Discovery | |
---|---|
Discovered by | Crossfield et al. |
Discovery site | Kepler Space Observatory |
Discovery date | July 18, 2016 [1] |
Transit | |
Orbital characteristics | |
0.106 +0.009 −0.013 [1] AU | |
Eccentricity | 0.110+0.199 −0.087 [1] |
24.159 ±0.004 [1] d | |
Star | K2-72 |
Physical characteristics | |
1.29 +0.14 −0.13 [1] R🜨 | |
Mass | ~2.21 [2] ME |
Temperature | 261.15 K (−12.00 °C; 10.40 °F) [2] |
K2-72e (also known by its EPIC designation EPIC 206209135.04), is a confirmed exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf star K2-72, the outermost of four such planets discovered in the system by NASA's Kepler spacecraft on its "Second Light" mission. It is located about 217.1 light-years (66.56 parsecs, or nearly 2.0538×1015 km) away from Earth in the constellation of Aquarius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. [3]
K2-72e is an Earth-sized exoplanet, meaning it has a mass and radius close to that of Earth. It has an equilibrium temperature of 261 K (−12 °C; 10 °F). It has a radius of 1.29 R🜨., [1] and a mass of 2.2 ME, depending on its composition. [2]
The planet orbits a (M-type) red dwarf star named K2-72, orbited by a total of four planets, of which K2-72e has the longest orbital period. The star has a mass of 0.27 M☉ and a radius of 0.33 R☉. It has a temperature of 3360 K and its age is unknown. In comparison, the Sun is 4.6 billion years old [4] and has a surface temperature of 5778 K. [5]
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 15.309. Therefore, it is too dim to be seen with the naked eye and can only be observed with a telescope.
K2-72e orbits its host star with an orbital period of 24 days and an orbital radius of about 0.1 times that of Earth's (compared to the distance of Mercury from the Sun, which is about 0.38 AU).
The exoplanet, along with K2-72c, were announced to be orbiting in the habitable zone of its parent star, the region where, with the correct conditions and atmospheric properties, liquid water may exist on the surface of the planet. K2-72e has a radius of 1.29 R🜨, so it is likely rocky. Its host star is a red dwarf, with about a fifth as much mass than the Sun does. As a result, stars like K2-72 have the ability to live up to 1–2 trillion years, hundreds of times longer than the Sun will live. [6]
The planet is very likely tidally locked, with one side of its hemisphere permanently facing towards the star, while the opposite side shrouded in eternal darkness.
It receives 11% more insolation than Earth does, so any oceans present are potentially vulnerable to boiling away, therefore possibly reducing the chance of habitability.
The planet, along with the other three planets in the K2-72 system, were announced in mid-July 2016 as part of the new results from the second mission of the Kepler spacecraft.
Kepler-37b is an exoplanet orbiting the star Kepler-37 in the constellation Lyra. As of February 2013, it is the smallest planet discovered around a main-sequence star, with a radius slightly greater than that of the Moon and slightly smaller than that of Mercury. The measurements do not constrain its mass, but masses above a few times that of the Moon give unphysically high densities.
Kepler-62e is a super-Earth exoplanet discovered orbiting within the habitable zone of Kepler-62, the second outermost of five such planets discovered by NASA's Kepler spacecraft. Kepler-62e is located about 990 light-years from Earth in the constellation of Lyra. The exoplanet was found using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. Kepler-62e may be a terrestrial or ocean-covered planet; it lies in the inner part of its host star's habitable zone.
Kepler-62f is a super-Earth exoplanet orbiting within the habitable zone of the star Kepler-62, the outermost of five such planets discovered around the star by NASA's Kepler spacecraft. It is located about 980 light-years from Earth in the constellation of Lyra.
Kepler-62c is an approximately Mars-sized exoplanet discovered in orbit around the star Kepler-62, the second innermost of five discovered by NASA's Kepler spacecraft around Kepler-62. At the time of discovery it was the second-smallest exoplanet discovered and confirmed by the Kepler spacecraft, after Kepler-37b. It was found using the transit method, in which the dimming that a planet causes as it crosses in front of its star is measured. Its stellar flux is 25 ± 3 times Earth's. It is similar to Mercury.
Kepler-61b is a super-Earth exoplanet orbiting within parts of the habitable zone of the K-type main-sequence star Kepler-61. It is located about 1,100 light-years from Earth in the constellation of Cygnus. It was discovered in 2013 using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured, by NASA's Kepler spacecraft.
Kepler-186f is an Earth-sized exoplanet orbiting within the habitable zone of the red dwarf star Kepler-186, the outermost of five such planets discovered around the star by NASA's Kepler spacecraft. It is located about 580 light-years from Earth in the constellation of Cygnus.
Kepler-438b is a confirmed near-Earth-sized exoplanet. It is likely rocky. It orbits on the inner edge of the habitable zone of a red dwarf, Kepler-438, about 472.9 light-years from Earth in the constellation Lyra. It receives 1.4 times our solar flux. The planet was discovered by NASA's Kepler spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the confirmation of the exoplanet on 6 January 2015.
Kepler-442b is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the K-type main-sequence star Kepler-442, about 1,206 light-years (370 pc) from Earth in the constellation of Lyra.
Kepler-296e is a confirmed super-Earth exoplanet orbiting within the habitable zone of Kepler-296. The planet was discovered by NASA's Kepler spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the discovery of the exoplanet on 26 February 2014.
Kepler-452b is a super-Earth exoplanet orbiting within the inner edge of the habitable zone of the sun-like star Kepler-452 and is the only planet in the system discovered by the Kepler space telescope. It is located about 1,400 light-years (430 pc) from Earth in the constellation of Cygnus.
K2-3d, also known as EPIC 201367065 d, is a confirmed exoplanet of probable mini-Neptune type orbiting the red dwarf star K2-3, and the outermost of three such planets discovered in the system. It is located 143 light-years away from Earth in the constellation of Leo. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. It was the first planet in the Kepler "Second Light" mission to receive the letter "d" designation for a planet. Its discovery was announced in January 2015.
Kepler-419c is a super-Jupiter exoplanet orbiting within the habitable zone of the star Kepler-419, the outermost of two such planets discovered by NASA's Kepler spacecraft. It is located about 3,400 light-years from Earth in the constellation Cygnus. The exoplanet was found by using the transit timing variation method, in which the variations of transit data from an exoplanet are studied to reveal a more distant companion.
Kepler-1229b is a confirmed super-Earth exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf Kepler-1229, located about 870 light years from Earth in the constellation of Cygnus. It was discovered in 2016 by the Kepler space telescope. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.
K2-72 is a cool red dwarf star of spectral class M2.7V located about 217 light-years away from the Earth in the constellation of Aquarius. It is known to host four planets, all similar in size to Earth, with one of them residing within the habitable zone.
K2-72c is a small exoplanet orbiting around the red dwarf star K2-72 approximately 227.7 light-years away. It is located in the inner edge of the habitable zone. K2-72c completes an orbit in 15.2 days, and it has a radius of only 86% of that of the Earth.
K2-72d is a small exoplanet orbiting around the red dwarf star K2-72 approximately 227.7 light-years away. K2-72d completes an orbit in 7.8 days, and it has a radius of only 73% of that of the Earth.
Kepler-277c is the third most massive and second-largest rocky planet ever discovered, with a mass about 64 times that of Earth. Discovered in 2014 by the Kepler Space Telescope, Kepler-277c is a Neptune-sized exoplanet with a very high mass and density for an object of its radius, suggesting a composition made mainly of rock with some amounts of water. Along with its sister planet, Kepler-277b, the planet's mass was determined using transit-timing variations (TTVs).
K2-288Bb is a super-Earth or mini-Neptune exoplanet orbiting in the habitable zone of K2-288B, a low-mass M-dwarf star in a binary star system in the constellation of Taurus about 226 light-years from Earth. It was discovered by citizen scientists while analysing data from the Kepler spacecraft's K2 mission, and was announced on 7 January 2019. K2-288 is the third transiting planet system identified by the Exoplanet Explorers program, after the six planets of K2-138 and the three planets of K2-233.
TOI-2257 b is an extremely eccentric (0.496) exoplanet in or near the circumstellar habitable zone of the star TOI-2257, 188 light-years away. It is likely a sub-Neptune exoplanet, with a mass of 5.71 Mearth and a radius of 2.19 Rearth. As a small planet in the habitable zone, it is included in the Planetary Habitability Laboratory's list of potentially habitable exoplanets.
K2-332 b is a potentially habitable Super-Earth or Mini-Neptune exoplanet with a radius of 2.2 earths. It is in the empirical habitable zone, receiving 1.17 times the light that Earth gets from the sun. Its star, K2-332, is type M4V, with a temperature of ~3300 K. It was detected using the transit method in 2016 and is 402 light-years away.