Those new additions bring the total number of potentially habitable planets detected by Kepler to 49. It's created to find rocky planets (not gaseous ones like Jupiter) that are located in habitable zones of stars where temperatures are temperate enough to potentially sustain life as we know it.
Due to their potential for hosting life, the 10 Earth-size planets are the most glamorous of the newly announced planets from Kepler.
The Kepler telescope detects the presence of planets by registering minuscule drops in a star's brightness that occurs when a planet crosses in front of it, a movement known as a transit. Space.com reports that the telescope stars at a single patch of sky looking for "alien planets".
With 219 potential new worlds out there, some could be habitable & 10 of them like our own.
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.
This is the final catalog detailing exoplanet candidates and confirmations from Kepler's survey taken during the first four years observing part of the constellation Cygnus. Planets in the second group are probably like cousins of Neptune with thick atmospheres and no surface to speak of.
The announcement came at a news conference Monday at NASA Ames Research Center in Mountain View. If it is confirmed, though, it may become the most Earth-like planet in the catalogue, so far. Ten of these planets are rocky and exist in their solar system's "Goldilocks zone" - the region where conditions are just right for liquid water to exist.
NASA is getting better at identifying Earth-sized exoplanets in other ways, too. It was created to survey part of the galaxy to see how frequent planets are and how frequent Earth-size and potentially habitable planets are.
The Kepler team found that planets which are about 1.75 times the size of Earth and smaller tend to be rocky, while those two- to 3.5 times the size of Earth become gas-shrouded worlds like Neptune.
"The Kepler data set is unique, as it is the only one containing a population of these near Earth-analogs, planets with roughly the same size and orbit as Earth", said Mario Perez, Kepler program scientist in the Astrophysics Division of NASA's Science Mission Directorate. Researchers are now using the Hubble Space Telescope to determine if these planets had atmosphere.
One research group took advantage of the Kepler data to make precise measurements of thousands of planets, revealing two distinct groups of small planets.
NASA said that the Spitzer, Hubble and Kepler will continue to conduct follow-up studies.