The paper discusses Kepler 186 exoplanetary system. It explains the technique of detecting Kepler 186 system, the structure, as well as its layout. Exoplanetary system denotes planets orbiting around a star other than the sun, or it is beyond the solar system (Charles, 2015).
Technique for Detecting Kepler 186
The method used to detect Kepler 186 is transit technique. A planet is described as transiting when it passes between its star and the planet Earth. As the planets of Kepler 186 pass between the Earth and the Kepler 186 star, the star's light is caused to dim, and this is detected by an instrument. Ideally, regular occurrence of the dimming at some fixed time is interpreted that a star (Kepler 186) is orbited by planets. This method offers detailed information on the Kepler planets in comparison to radial velocity (Rudolf, 2008).
The size of the Kepler 186 star is known, for that reason, dimming in the star's luminosity offers an accurate interpretation of the sizes of the planets orbiting the star (Tim, 2016). Additionally, the compositions of these planets can be interpreted. For instance, the atmospheres of these planets are presumed through analyzing or interpreting the light, which is absorbed by constituents as the planet passes via its atmosphere. The use of radial velocity as well as transit method can be used to approximate the mass, sizes as well as the composition of the planets.
A drawback of Transit Method
Ideally, there must be a transit for the detection. Someone making the observation must precisely align as well as be at an appropriate time for the detection of the transit. It implies that the method is only applicable to limited stars. Nonetheless, the challenge can be addressed through the use of NASA space dependent Kepler mission, which can scan over a hundred thousand stars at once over many years. Currently, NASA space dependent Kepler mission has offered many exoplanets (Rudolf, 2008).
Kepler 186 denotes a star, which is within the constellation Cygnus. It has mass, which is 0.48 times that of the sun. The radius of Kepler 186 is 0.47 times that of the sun. The average surface temperature of Kepler 186 is 3788 K. M0V denotes the spectral classification or taxonomy of the star and is considered redder as well as dimmer in comparison with the G2V of the sun (Rudolf, 2008). The M-category dwarfs constitute seventy percent of Kepler 186 within the MWG (Milky Way Galaxy). Kepler 186 system is made up of five planets namely b, c, d, e, as well as f (Rudolf, 2008).
The radius of Kepler 186b is approximately 1.07 of the Earth’s radii. The Kepler 186b is about 0.0343 AU from Kepler 186. It completes one orbit of the star once each 3.8867907 days of the Earth (Charles, 2015). The radius of Kepler 186c is approximately 1.25 of the Earth's radii. The distance of Kepler 186c is 0.0451 AU from Kepler 186. It takes 7.267302 days of the Earth to complete one orbit of the star. The extreme pressure due to gravity, as well as the atmosphere of the planet, makes it possible for liquid water. Ideally, the high temperature of the planet would evaporate water if it were on the Earth’s pressure (Charles, 2015).
The radius of Kepler 186d is approximately 1.4 of the Earth’s radii (Charles, 2015). The distance of the planet from the star is about 0.0781 AU. It takes 13.342996 of the Earth’s days to complete one orbit of the star. The temperature of the planet is about 1560C (Charles, 2015). The radius of Kepler 186e is about 1.27 that of the Earth’s radii. The distance of the planet from Kepler 186 is approximately 0.11 AU. The planet takes 22.407704 days of the Earth to complete one orbit of the star. The temperature of the planet is about 880C that makes it almost impossible to have liquid water on its surface, particularly on its poles.
The last planet within this system is Kepler 186f. Its radius is about 1.11 that of the Earth (Charles, 2015). The distance of this planet from Kepler 186 is about 0.356 AU. It takes 129.9459 days of the Earth to complete one orbit of the star. The temperature of the planet is -930C that is colder in comparison to Earth’s 254.3 K temperature or Mars’ 210 K temperature, although it is warmer in comparison to Jupiter’s 110 K temperature (Charles, 2015).
Habitable zone can be defined as distances between the planets and the star, from which the temperature of the planets can permit liquid water oceans. There is no planet of the Kepler 186 system that is within a habitable zone. The extreme pressure due to gravity, as well as the atmosphere of the planet (Kepler 186 c), makes it possible for liquid water. The temperature of the planet (Kepler 186 d) is about 1560C (Charles, 2015). The temperature of the planet (Kepler 186 e) is about 880C that makes it almost impossible to have liquid water on its surface, particularly on its poles. The temperature of the planet (Kepler 186 f) is -930C that is colder in comparison to Earth’s 254.3 K temperature or Mars’ 210 K temperature, although it is warmer in comparison to Jupiter’s 110 K temperature (Charles, 2015).
References
Charles, C. (2015). Astrobiology. [Place of Publication not identified]: John Wiley & Sons.
Rudolf, D. (2008). Extrasolar Planets: Formation, Detection, and Dynamic. Weinheim [Germany]: Wiley-VCH.
Tim, L. (2016). Earth System Science: A very Short Introduction. [Place of Publication not identified]: Oxford Univ Press.
