Eight More Exoplanets Found in Goldilocks Zone

Posted on January 7, 2015

Exoplanet orbiting star that has formed a planetary nebula

Astronomers from the Harvard-Smithsonian Center for Astrophysics (CfA) have discovered eight more exoplanets in the Goldilocks zone of their stars. A planet in the Goldilocks zone orbits its star at a distance where it is possible for liquid water to exist on its surface. The new planets were announced during a press conference at a meeting of the American Astronomical Society. This artist's conception above shows an Earth-like planet orbiting a star that has formed a planetary nebula.

The eight new exoplanets include two that astronomers say are the most Earth-like of any exoplanet discovered to date. These two planets - Kepler-438b and Kepler-442b - both orbit red dwarf stars that are smaller and cooler than our Sun. Kepler-438b circles its star every 35 days and Kepler-442b orbits it star every 112 days. Astronomers say Kepler-438b has a diameter 12% bigger than Earth and has a 70% chance of being rocky. Kepler-442b is about 1/3 the mass of the Earth and has a 60% chance of being rocky. Kepler-438b is 470 light-and Kepler-442b is 1,100 light-years away.

David Kipping of the CfA says in a statement, "We don't know for sure whether any of the planets in our sample are truly habitable. All we can say is that they're promising candidates."

The astronomers studied planetary candidates identified by NASA's Kepler mission and then used a computer program called BLENDER to determine that the candidates are statistically likely to be planets. The team then studied the planets for a year following the BLENDER analysis using high-resolution spectroscopy, adaptive optics imaging, and speckle interferometry.

NASA notes in a press release that the new discoveries brings the total number of planets found using its Kepler Space Telescope to over 1,000.

Photo: David A. Aguilar (CfA)