A rocky “super-Earth” exoplanet located in its star’s habitable zone just 14 light years from our solar system may be experiencing a runaway greenhouse effect like that on Venus and therefore not be habitable for life.
Wolf 1061c, one of three planets orbiting the star Wolf 1061, discovered by scientists at the University of New South Wales in Australia in December 2015, is located in the star’s habitable zone, where temperatures would allow liquid water to exist on its surface.
At 14 light years away, it is relatively close to Earth though more distant than Proxima Centauri b, a potentially habitable planet orbiting the star Proxima Centauri, just four light years away.
However, San Francisco State University astrophysicist Stephen Kane suspects that Wolf 1061c is more akin to Venus than to Earth, and may be experiencing a runaway greenhouse effect like the one that resulted in Venus’s oceans boiling away.
Venus is believed to have once been Earth-like with liquid oceans on its surface only to have experienced extreme warming when carbon dioxide from its volcanoes entered its atmosphere, trapping the Sun’s heat and raising surface temperatures to around 880 degrees Fahrenheit.
According to the initial discoverers of Wolf 1061c, the star’s habitable zone ranges from 0.092 to 0.18 AU or astronomical units, with one astronomical unit equal to the average Earth-Sun distance of 93 million miles.
Its habitable zone could extend over a larger region between 0.073 and 0.19 AU from the star, they theorized.
Using six telescopes at the Center for High Angular Resolution Astronomy in California, Kane and his team of researchers determined the star’s habitable zone to actually range from 0.11 to 0.21 AU.
Located at the inner edge of this revised habitable zone, Wolf 1061c is likely close enough to the star to be experiencing the same runaway greenhouse effect that occurred on Venus.
Even if the planet did not experience this, “oscillations in its orbit” the researchers detected prevent scientists from being able to learn about its climate.
That could change when more advanced telescopes such as the James Webb Space Telescope and the Wide Field Infrared Survey Telescope make it possible to directly observe the planet sometime during the 2020s.
Kane and his team are publishing their findings in an upcoming issue of the Astrophysical Journal.