Using data from the now ‘retired’ Kepler space telescope, citizen scientists have discovered a planet double the size of Earth, orbiting its sun in the habitable zone.
NASA has recently retired the legendary Kepler Space Telescope used to uncover Earth-size planets orbiting other stars.
The spacecraft was launched on March 7, 2009, into an Earth-trailing heliocentric orbit where it remained until recently, exploring the cosmos in search for new, Earth-like planets.
After nine years of operation, the telescope’s reaction control system fuel was depleted, and NASA announced the space telescope’s retirement on October 30, 2018.
But even though the telescope is out of function, it doesn’t mean it still can’t help us find new worlds.
Using data obtained by Kepler, citizen astronomers have found an alien planet dubbed K2-288Bb.
It could be either a rocky world like ours, but also a gaseous planet like Neptune.
Its size is rare among exoplanets.
“It’s a very exciting discovery due to how it was found, its temperate orbit and because planets of this size seem to be relatively uncommon,” explained Adina Feinstein, a University of Chicago graduate student who discussed the discovery on Monday, Jan. 7, at the 233rd meeting of the American Astronomical Society in Seattle.
She is also the lead author of a paper describing the new planet accepted for publication by The Astronomical Journal.
The exoplanet is located around 226 light-years away from Earth, tucked away in the constellation Taurus.
The planet lies in a solar system known as K2-288, which contains a pair of dim, cool M-type stars separated by about 5.1 billion miles (8.2 billion kilometers) – roughly six times the distance between Saturn and the Sun.
The brighter star is about half as massive and large as the Sun, while its companion is about one-third the Sun’s mass and size, explains NASA in a statement.
The newly found planet, K2-288Bb, is believed to orbit the smaller, dimmer star in around 31.3 days.
The planet was long searched for in 2017, when Feinstein and Makennah Bristow, an undergraduate student at the University of North Carolina Asheville, worked as interns with Joshua Schlieder, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland searching for Kepler data that could show evidence of new planets.
They looked for transits, regular dimming that occurs on a star when a cosmic object moves across the star’s surface facing Earth.
After examining data from the fourth observational campaign made by Kepler, the researchers noticed two likely planetary transits. However, they required a third transit before they could say they’ve found a new world.
That third transit wasn’t observed.
However, it turned out that more than a year ago, the researchers missed some of the data gathered by Kepler.
During Kepler’s K2 mode, the spacecraft repositioned itself in a new patch of the sky.
After the repositioning took place, astronomers were worried that this change could cause systematic errors in measurements.
“Re-orienting Kepler relative to the Sun caused minuscule changes in the shape of the telescope and the temperature of the electronics, which inevitably affected Kepler’s sensitive measurements in the first days of each campaign,” said co-author Geert Barentsen, an astrophysicist at NASA’s Ames Research Center in California’s Silicon Valley and the director of the guest observer office for the Kepler and K2 missions.
As explained by NASA, to deal with the issue, early version of the software that was used to prepare the data for planet-finding analysis ignored the first days of observations, which is where the third transit was actually hiding.
“We eventually re-ran all data from the early campaigns through the modified software and then re-ran the planet search to get a list of candidates, but these candidates were never fully visually inspected,” explained Schlieder, a co-author of the paper.
“Inspecting, or vetting, transits with the human eye is crucial because noise and other astrophysical events can mimic transits.”