Simulated view of the Kepler-159 system. Kepler-159b and c are planets that were detected by the Kepler spacecraft. Kepler-159d was discovered at Western University on the basis of its gravitational effects on 159b and 159c. Click above for a larger HD version.

Chris Fox
Dept. of Physics and Astronomy, Western University, London ON CANADA

Paul Wiegert
Dept. of Physics and Astronomy, Western University, London ON CANADA
Centre for Planetary Science and Exploration (CPSX), London ON CANADA

9 October 2018

On October 9th 2018 in the scientific journal Monthly Notices of the Royal Astronomical Society, Canadian astronomers reveal a new planet in the distant Kepler-159 planetary system. This new exoplanet was discovered by scientists working at Western University's Department of Physics and Astronomy and the Centre for Planetary Science and Exploration (CPSX).

The as-yet unnamed planet with the provisional designation Kepler-159d has a mass comparable to that of Saturn, the second-largest planet in our solar system, and like Saturn is likely mostly composed of gases with no distinct solid surface. Whether 159d has rings or moons like Saturn does is unknown. 159d *is* known to orbit within its star's Habitable Zone where temperatures are in the range suitable for Earth-life but there is no information on whether there is actually any life in the system.

The central star of this planetary system is about 380 parsecs (1200 light-years) away , and is a red dwarf star (spectral class M0V) with a mass estimated at 52% of that of our Sun. Its surface temperature is about 3600 Celsius (3893 Kelvin) while the Sun's is 5500C (5770 K) (Muirhead et al. 2012; Mathur et al. 2017)

Kepler-159b and 159c are two planets already known in the system, detected from their passages in front of the Kepler-159 star by the Kepler planet-hunting spacecraft. Kepler-159d was not seen by the Kepler planet-hunters, rather it was variations in the orbits of Kepler-159b and c that allowed researchers at Western University in London Canada to deduce the presence of planet 159d.

Chris Fox, lead author on the paper, first reported the new planet at a recent scientific conference in Cambridge England. Said Fox, "Ever since I was a kid, I've wanted to visit alien planets. Finding new worlds is the next best thing."

Reference list

Mathur S., et al., 2017, "Revised Stellar Properties of Kepler Targets for the Q1-17 (DR25) Transit Detection Run", ApJS, 229, 30. [link]
Muirhead P., et al., 2012, "Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars", ApJ, 750, 2, L37. [link]

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