Revived Kepler telescope finds first exoplanet

Crippled spacecraft turns up new worlds while balancing on sunlight

Kepler telescope

SECOND LIFE  The revived Kepler telescope, shown in this artist’s illustration, will stare at a different patch of sky every 80 days while using sunlight to stay balanced.

T. Pyle, JPL-Caltech, NASA Ames

The Kepler space telescope has bagged its first confirmed planet since being benched in the summer of 2013 by a broken part used to steady the spacecraft (SN: 9/21/13, p. 18).

The planet, named HIP 116454b, sits 180 light-years away in the constellation Pisces. Kepler detected the planet, which is about 2.5 times as wide as Earth, as a brief dip in starlight as HIP 116454b passed between its sun and the telescope. Follow-up observations at the Telescopio Nazionale Galileo, an Italian telescope on the Canary Islands, provided the planet’s mass: roughly 12 times that of Earth. HIP 116454b is probably either a water world or a mini-Neptune, astronomers report in a paper posted online December 18 and accepted to the Astrophysical Journal.

The discovery is the first for the K2 mission, Kepler’s second chance at life (SN: 6/28/14, p. 7). After losing two of its reaction wheels, which balanced the spacecraft, Kepler could no longer stay steady enough to stare at stars and detect planets. Engineers proposed pointing Kepler’s solar panel roof toward the sun and using the balanced pressure from sunlight to steady the spacecraft. HIP 116454b turned up in a February 2014 test run to see if the plan would work.

Christopher Crockett is an Associate News Editor. He was formerly the astronomy writer from 2014 to 2017, and he has a Ph.D. in astronomy from the University of California, Los Angeles.

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