Scientists Catalog All of the Exoplanets That Could Be "New Earths"

Wednesday, 03 August 2016 - 4:18PM
Earth
Astronomy
Wednesday, 03 August 2016 - 4:18PM
Scientists Catalog All of the Exoplanets That Could Be "New Earths"
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Over the last few years, scientists have found hundreds of new exoplanets, many of which lie in their stars' habitable zones. Now, a team of scientists has created a full catalog of potentially habitable exoplanets, or the best candidates to be "second Earths."

The catalog, the most comprehensive guide to Earth-like exoplanets thus far, will be published in Astrophysical Journal, and contains 216 exoplanets found by Kepler. They all lie within the "Goldilocks zone," or the area that is far enough from their star that liquid water wouldn't evaporate, and close enough that it wouldn't freeze. Of those 216 planets, the researchers also list the 20 planets that are most likely to be Earth-like, which are detailed in the chart below:

Click for an enlarged version of the image.



Opening quote
"This is the complete catalog of all of the Kepler discoveries that are in the habitable zone of their host stars," lead author Stephen Kane, a physicist and astronomer at San Francisco State University, said in a statement. "That means we can focus in on the planets in this paper and perform follow-up studies to learn more about them, including if they are indeed habitable."
Closing quote

In order to narrow down the field to twenty, the researchers sorted the planets by their position in the habitable zone—namely, whether they were squarely in the habitable zone or on the outskirts. Then, of the planets that were in the most optimal position, they sorted the candidates according to size, since smaller planets are more likely to be rocky while larger planets could be gas giants. 

Opening quote
"There are a lot of planetary candidates out there, and there is a limited amount of telescope time in which we can study them," Kane said. "This study is a really big milestone toward answering the key questions of how common is life in the universe and how common are planets like the Earth."
Closing quote

For this study, the researchers studied more than 4,000 discovered exoplanets over three years. They have already begun collecting more data on the most promising candidates, and they hope that this catalog will help astronomers focus their research when searching for Earth-like planets and even extraterrestrial life.

Opening quote
"It's exciting to see the sheer amount of planets that are out there, which makes you think that there is zero chance of there not being another place where life could be found," said co-author Michelle Hill.
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