Discovery expands search for Earth-like planets

This artist’s concept depicts Kepler-186f , the first validated Earth-size planet to orbit a distant star in the habitable zone.
Image Credit: Nasa Ames/SETI Institute/JPL-Caltech
Date:15 October 2014

A newly discovered planet in a binary star system located 3 000 light-years from Earth is expanding astronomers’ notions of where Earth-like – and even potentially habitable – planets can form, and how to find them.

At twice the mass of Earth, the planet orbits one of the stars in the binary system at almost exactly the same distance from which Earth orbits the Sun. However, because the planet’s host star is much dimmer than the sun, the planet is much colder than the Earth – a little colder, in fact, than Jupiter’s icy moon, Europa.

Four international research teams, led by Professor Andrew Gould of Ohio State University, published their discovery in the journal Science. Their study provides the first evidence that terrestrial planets can form in orbits similar to

Earth’s, even in a binary star system where the stars are not very far apart. Although this planet itself is too cold to be habitable, the same planet orbiting a Sun-like star in such a binary system would be in the so-called “habitable zone” – the region where conditions might be right for life.

“This greatly expands the potential locations to discover habitable planets in the future,” said Scott Gaudi, professor of astronomy at Ohio State. “Half the stars in the galaxy are in binary systems. We had no idea if Earth-like planets in Earth-like orbits could even form in these systems.”

Source: Ohio State University