May 30. (EUROPE PRESS) –
Astronomers, with the help of citizen scientists, have discovered what may be the last planets that the Kepler space telescope observed before running out of fuel in 2018.
The team, led by researchers from MIT and the University of Wisconsin-Madison, reviewed the past week of high-quality data from the telescope and detected three stars, in the same part of the sky, that appeared to dim briefly. The scientists determined that two of the stars each harbor a planet, while the third houses a “candidate” planet that has not yet been verified.
The two validated planets are K2-416 b, a planet about 2.6 times the size of Earth that orbits its star every 13 days, and K2-417 b, a slightly larger planet that has a just over three times the size of Earth and revolving around its star every 6.5 days. Because of their size and proximity to their stars, both planets are considered “hot mini-Neptunes.” They are about 400 light years from Earth.
The planet candidate is EPIC 246251988 b, the largest of the three worlds at nearly four times the size of Earth. This Neptune-sized candidate orbits its star in about 10 days and is slightly farther away, 1,200 light years from Earth.
“We have found what are probably the last planets ever discovered by Kepler, in data taken while the spacecraft literally in the last“, says it’s a statement Andrew Vanderburg, an assistant professor of physics at MIT’s Kavli Institute for Astrophysics and Space Research. “The planets themselves are not particularly unusual, but their atypical discovery and their historical importance make them interesting.”
The team has published their discovery in the journal Monthly Notices of the Royal Astronomical Society.
In 2009, NASA launched the Kepler telescope into space, where it followed Earth’s orbit and continuously monitored millions of stars in a part of the northern sky. Over four years, the telescope recorded the brightness of more than 150,000 stars, which astronomers used to discover thousands of possible planets beyond our solar system.
Kepler continued to observe beyond its original mission of three and a half years, until May 2013, when the second of four reaction wheels failed. The wheels served as the spacecraft’s gyroscopes, helping to keep the telescope pointed at a particular point in the sky. Kepler’s observations were put on hold while scientists searched for a solution.
A year later, Kepler restarted as “K2,” a reworked mission that used wind from the sun to balance the unstable spacecraft in a way that kept the telescope relatively stable for a few months at a time, a period called the campaign. K2 continued for another four years, observing over half a million more stars before the spacecraft finally ran out of fuel during its 19th campaign. Data from this latest campaign comprised just one week of high-quality observations. and another 10 days of noisier measurements as the spacecraft rapidly lost fuel.
“We were curious to see if we could glean anything useful from this short data set,” says Vanderburg. “We tried to see what latest information we could extract.”
