If so, promising planets may have been sterilized by solar flares or frozen in the past, which wouldn't be reflected in present-day habitable-zone calculations.

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This range is called the habitable zone - or colloquially, the Goldilocks zone.

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The astronomers who will use these telescopes are particularly interested in finding any Earth-like objects in the so-called habitable zone around a star, where temperatures permit water to exist in a liquid state.

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Fischer is going after Earth-like planets in the habitable zone.

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"What's particularly interesting is four new planets - less than twice the size of Earth - that are potentially in the habitable zone, the location around a star where it could potentially have liquid water to sustain life, " Dr Burke told BBC News.

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They were also able to extrapolate whether those super-Earths were likely to be orbiting in the habitable zone around the star.

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This past December, for example, NASA's Kepler space telescope confirmed its first planet in the habitable zone, a "super Earth" known as Kepler-22b that's thought to be 2.4 times as wide as our planet.

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The habitable zone is the region of a planetary system which is neither too hot nor too cold - such that water on the surface of a planet will neither evaporate nor freeze, but instead can stay liquid.

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