NASA discovers 10 new Earth-size exoplanets


It's important to note that NASA's rules for what defines a "planet" are incredibly exacting.

So far, its has identified 4,034 planet candidates, 2,335 of which have been verified as exoplanets.

One of the most notable new additions is known as KOI-7711, indicated by the yellow dot just to the right of Earth on the plot above (as "7711.01").

With the release of this catalog-derived from data publicly available on the NASA Exoplanet Archive-there are now 4,034 planet candidates identified using the Kepler telescope, which hunts for planets by detecting the minuscule drop in a star's brightness during transit (when a planet crosses in front of it).

One of Kepler's most high-profile discoveries was of the Trappist system, a remarkable collection of seven Earth-like planets all orbiting a single star.

Kepler habitable zone planet candidates, plotted by temperature of star and energy received from its star.

The goal has been to discover more Earth-like planets in the habitable zone of a star, where water can pool on the surface of a planet and potentially support life.

With this new data, the catalog suggests that about half of the exoplanets in our galaxy are either gaseous, with no surface, or have such a heavy atmosphere that life as we know it would not be possible. Kepler has been surveying the Cygnus constellation since 2009, and during that time scientists have found more than 5,000 potential exoplanets in an area of the sky about 3,000 light-years away from Earth.

Below is a plot showing only the small subset of relatively Earth-sized planet candidates.

The findings were presented at a news conference Monday at NASA's Ames Research Center in California's Silicon Valley.

Read: A Planet Hotter Than Most Stars? It has shown us these terrestrial worlds, and we still have all of this work to do to really understand how common Earths are in the galaxy.

Although the Kepler mission has yet to fulfill one of its goals, which is determining the fraction of sun-like stars hosting Earth-like planets in our galaxy, these data will help astronomers determine that number in the next few years, the researchers said. While the catalog from the Kepler mission, the first four years Kepler was in space, will not change after Monday, the catalog from K2 may change and grow in the future.

In the search for life, Fulton believes it will be better to focus on super-Earths. With the launch of our Transiting Exoplanet Survey Satellite (TESS) and the James Webb Space Telescope (JWST) in 2018, we're going to search for planets nearest the sun and measure the composition of their atmospheres. In the middle are roughly Neptune-size worlds and at the other end of the scale are smaller Earth-analogues.

One research group took advantage of the Kepler data to make precise measurements of thousands of planets, revealing two distinct groups of small planets. "We stopped doing it that way", she said during a NASA podcast interview.