The Kepler mission has discovered 1,284 planets – the single largest finding of planets to date, according to Princeton associate research scholar Timothy Morton.
Ellen Stofan, chief scientist at NASA Headquarters in Washington was optimistic about finding another Earth like ours.
“This announcement more than doubles the number of confirmed planets from Kepler,” said Stofan,
“This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”
Since launching in 2009, Kepler’s goal goal has been to discover more Earth-like planet. It has been watching more than 150,000 stars in one specific part of the sky to discover exoplanets, based on the slight dimming of stars as likely planets pass across them. Kepler is searching for a planet where water can pool on its surface.
Scientists performed analysis on the planet hunter’s July 2015 planet candidate catalog, which identified 4,302 potential planets. For 1,284 of the candidates, the probability of being a planet is greater than 99% – the minimum required to earn the status of “planet.” An additional 1.327 candidates will require additional study because they do not meet the 99% threshold. The remaining 707 are more likely to be some other astrophysical phenomena, says NASA.
“Planet candidates can be thought of like bread crumbs,” Timothy Morton, associate research scholar at Princeton University in New Jersey and lead author of the scientific paper published in The Astrophysical Journal.
“If you drop a few large crumbs on the floor, you can pick them up one by one. But, if you spill a whole bag of tiny crumbs, you’re going to need a broom. This statistical analysis is our broom.”
Morton used a technique to assign each Kepler candidate a planet-hood probability percentage – the first such automated computation on this scale.
In the newly-confirmed group of planets, nearly 550 could be Earth-like rocky planets, based on their size. Nine of these planets orbit in their sun’s habitable zone, which is the distance from a star where orbiting planets can have surface temperatures that enable liquid water to pool on its surface. With the addition of these 9, 21 exoplanets are now known to be members of this select group.