New Super-Earth May Be Just Right to Support Life

Posted November 9th, 2012 at 1:10 pm (UTC-5)
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An international team of astronomers says it has found a new planet – a relatively near 42 light years away – that could have liquid water and an Earth-like climate.

The dwarf star known as HD 40307 was already known to have three planets orbiting it. Using a new and more sensitive technique for analyzing the light emitted by the star, the scientists identified three additional planets.

Two orbit with the original three, close in to the star. The third, with a mass seven times that of Earth, circles in what's called the “habitable zone.” That's the just-right distance from a star where temperatures on an orbiting planet are neither too hot nor too cold for liquid water to exist – a widely accepted requirement for life as we know it.

One of the ways astronomers can locate planets in distant solar systems is by measuring changes in the wavelength of light from the star. The shifts occur when an orbiting planet's gravity causes the star to wobble.

The team, led by researchers from the University of Hertfordshire in Britain, noticed that regular stellar activity produced more blue light, but the red half of the wavelength was more stable. Such changes signaled the influence of an orbiting planet.

The research, published in the journal Astronomy and Astrophysics, has been greeted with both praise and skepticism. Previous reports of Earth-like planets have been discounted, and this finding has not yet been confirmed by other teams. If it is, HD 40307-g would be far closer than Kepler 22-b, the first planet ever discovered in a habitable zone, some 600 light-years away.