Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2020 April 28
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The Kepler-90 Planetary System
Illustration Credit: NASA Ames, Wendy Stenzel

Explanation: Do other stars have planetary systems like our own? Yes -- one such system is Kepler-90. Catalogued by the Kepler satellite that operated from Earth orbit between 2009 and 2018, eight planets were discovered, giving Kepler-90 the same number of known planets as our Solar System. Similarities between Kepler-90 and our system include a G-type star comparable to our Sun, rocky planets comparable to our Earth, and large planets comparable in size to Jupiter and Saturn. Differences include that all of the known Kepler-90 planets orbit relatively close in -- closer than Earth's orbit around the Sun -- making them possibly too hot to harbour life. However, observations over longer time periods may discover cooler planets farther out. Kepler-90 lies about 2,500 light years away, and at magnitude 14 is visible with a medium-sized telescope toward the constellation of the Dragon (Draco). The exoplanet-finding mission TESS was launched in 2018, while missions with exoplanet finding capability planned for launch in the next decade include NASA's JWST and WFIRST.

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