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Kepler-90i (also known by its Kepler Object of Interest designation KOI-351 i)[2] is a super-Earth exoplanet with a radius 1.32[2] that of Earth, orbiting the early G-type main sequence star Kepler-90 every 14.45 days, discovered by NASA's Kepler spacecraft.[3][4] It is located about 2,545 light-years (780 parsecs, or nearly 2.4078×1016 km) from Earth in the constellation Draco. The exoplanet is the eighth in the star's multiplanetary system. As of December 2017, Kepler-90 is the star hosting the most exoplanets found. Kepler-90i was found with the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured, and by a newly utilized computer tool, deep learning, a class of machine learning algorithms.[3][5][6]

Exoplanet List of exoplanets
Kepler-90 MultiExoplanet System - 20171214.jpg
Comparison of the Kepler-90 MultiExoplanetary System with that of the Inner Solar System (14 December 2017).
Parent star
Star Kepler-90
Constellation Draco
Right ascension (α) 18h 57m 44.04s
Declination (δ) +49° 18′ 18.6″
Apparent magnitude (mV) 13.89[1]
Distance 2545 ly
(780 pc)
Spectral type G0V
Mass (m) 1.2 (± 0.1)[2] M
Radius (r) 1.2 (± 0.1)[2] R
Temperature (T) 6080[2] K
Metallicity [Fe/H] −0.12 (± 0.18)[2]
Age ~2 Gyr
Physical characteristics
Radius (r) 1.32±0.21[2] R
Temperature (T) 709 K (436 °C; 817 °F)[2]
Orbital elements
Semi-major axis (a) 0.107+0.025
[3] AU
Orbital period (P) 14.44912±0.00020[2] d
Inclination (i) 89.20 +0.59
Discovery information
Discovery date 2017 Shallue et al.[2][3]
Discoverer(s) Kepler spacecraft[3]
Discovery method Transit[2] and deep learning, a class of machine learning algorithms.[3]
Discovery status Published[3]
Other designations
KOI-351 i; KIC 11442793 i; iWISE J185744.03+491818.5 i; i2MASS J18574403+4918185 i; iKepler-90 i[2]
Database references
Extrasolar Planets
Exoplanet Archive data
Open Exoplanet Catalogue data



Mass, radius and temperatureEdit

Kepler-90i is a super-Earth exoplanet with a radius of 1.32 R[2], indicating that it is small enough to be rocky. With an Earth-like composition, Kepler-90i would have a mass of about 2.5 M.[citation needed] It has an equilibrium temperature of 709 K (436 °C; 817 °F), similar to the average temperature of Venus.

Host starEdit

The planet orbits a (G-type) star named Kepler-90. The star has a mass of 1.2 M and a radius 1.2 R. It has a surface temperatures of 6080 K and has an estimated age of around 2 billion years, with considerable uncertainty. In comparison, the Sun is about 4.6 billion years old[7] and has a surface temperature of 5778 K.[8]

The star's apparent magnitude, or how bright it appears from Earth's perspective, is 14. It is too dim to be seen with the naked eye.

Orbital characteristicsEdit

Kepler-90i orbits its host star about every 14.45 days with a semi-major axis of 0.1234 AU.


In 2009, NASA's Kepler spacecraft was observing stars on its photometer, the instrument it uses to detect transit events, in which a planet crosses in front of and dims its host star for a brief and roughly regular period of time. In its last test, Kepler observed 50000 stars in the Kepler Input Catalog, including Kepler-90; the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the bunch for follow-up at observatories. Discovery of the exoplanet was aided by a newly utilized computer tool, deep learning, a class of machine learning algorithms.[3][5]

Kepler-90 exoplanetary system compared to our Solar System

See alsoEdit


  1. ^ Staff (31 December 2013). "TEPcat: Kepler-90h". Keele Astrophysics Group. Retrieved 14 December 2017. 
  2. ^ a b c d e f g h i j k l m n "Kepler-90 i". NASA Exoplanet Archive. Retrieved 14 December 2017. 
  3. ^ a b c d e f g h Shallue, Christopher J.; Vanderburg, Andrew (16 December 2017). "Identifying Exoplanets With Deep Learning: A Five Planet Resonant Chain Around Kepler-80 And An Eighth Planet Around Kepler-90" (PDF). Retrieved 14 December 2017. 
  4. ^ St. Fleur, Nicholas (14 December 2017). "An 8th Planet Is Found Orbiting a Distant Star, With A.I.'s Help". The New York Times. Retrieved 15 December 2017. 
  5. ^ a b Chou, Felecia; Hawkes, Alison; Northon, Karen (14 December 2017). "Release 17-098 – Artificial Intelligence, NASA Data Used to Discover Eighth Planet Circling Distant Star". NASA. Retrieved 14 December 2017. 
  6. ^ Chou, Felicia; Hawkes, Alison; Landau, Elizabeth (14 December 2017). "Artificial Intelligence, NASA Data Used to Discover Eighth Planet Circling Distant Star". NASA. Retrieved 15 December 2017. 
  7. ^ Cain, Fraser (16 September 2008). "How Old is the Sun?". Universe Today. Retrieved 14 December 2017. 
  8. ^ Cain, Fraser (15 September 2008). "Temperature of the Sun". Universe Today. Retrieved 14 December 2017. 

Coordinates:   18h 57m 44.04s, +49° 18′ 18.6″