Kepler-90

1.60 ± 0.5 L ☉

Kepler -90 ( also KOI -351 ) is an approximately 2500 light years distant main sequence star in the Milky Way.

According to the latest research, Kepler - 90 has a planetary system with seven planets, which is similar in structure to the solar system: star close, compact, rocky planets and distant, large gas planets. The five inner planets are due to their size to the super-Earths or Mini - Neptunes. The two outer planets are gas giants. However, the planetary system to Kepler -90 is crowded much closer. The outermost of the seven previously discovered planet orbits the star at about the same distance as the earth the sun.

To be designated as Kepler -90 star KOI -351 was called. KOI stands for Kepler Object of Interest. Thus, the star has been observed during the NASA mission of the space telescope Kepler 2008-2013 and was able to be classified as a candidate for the existence of extrasolar planets ( exoplanets short ). Kepler -90 is currently the star with the most known exoplanets (as of November 2013).

Planet

All the planets have been discovered by the transit method. This enables a reliable determination of the size of the planet, but there is no direct measurement of their mass. Since the planets have been discovered at the same time, follows its name to the distance to the star, Kepler -90 b is the innermost and Kepler -90 h, the outermost of the seven known planets.

Kepler -90 b and c

Kepler -90 b is 31 percent larger than the Earth, Kepler -90 c is 19 percent larger. Such small planets are still at the limit of detectability, since the planets in transit reduce the apparent brightness of the star only slightly.

Besides the size of these planets is striking that they are in a so-called 5:4 resonance. This means that in the time of Kepler -90 b orbits the star five times, Kepler -90 c orbits the star exactly four times. This means that the planet always meet at the same positions. Similar resonances also exist in the inner moons of Jupiter. For more dynamic interactions with the other planets there is no clue.

Kepler -90 d, e and f

Planet Kepler -90 d orbits the star with a period of 60 days. This is comparable to the orbital period of Mercury around the Sun. The radius is 2.9 times as large as that of the earth. It is thus likely to be a so-called super-Earth or a mini - Neptune. Since the mass is only estimated, it is not yet possible to decide which of the two classes belonging to this planet.

The planet Kepler -90 e is as large as Kepler -90 d ( 2.7 times Earth's radius ) approximately. Also, the planet Kepler -90 f is similar in size to Kepler -90 d, and e Furthermore, with the 2.9 -times the earth's radius are these three planets in nearly 2:3:4 resonance and their orbits are nearly circular.

KOI -351 g, and h

The gas giant Kepler -90 and Kepler - g 90 h have an approximately 8-fold and 11 times the diameter of Earth. Both planets orbit their star on the long-period outer tracks in 211 or 331 days. This has similarities with the solar system, in which it also claimed the four rocky planets (Mercury, Venus, Earth and Mars), two gas giants ( Jupiter and Saturn ) with 10 - or is 8x the diameter of Earth.

Kepler -90 g could be any orbited by a moon. The distance of the most distant planet, Kepler -90 h, to its star is about 1.01 AU. This therefore corresponds to the mean distance of the earth to the sun.

Swell

• Individual star fifth size and darker
• Dragon ( constellation )
• Star with exoplanet