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Astronomy News - Exploring Space

Kepler finds lowest mass planet to date - 19th January 2011


The Kepler telescope, which was designed to find Earth-like planets, has broken the record for finding the smallest planet outside the solar system to date. The planet, dubbed Kepler 10b, is less than five times heavier than Earth and has only 1.4 times the diameter. The discovery was announced at the American Astronomical Society meeting earlier this week. 


Kepler detects planets using the transit method, which involves measuring the tiny drop in the apparent brightness of a star as a planet passes infront of it. The size of the planet can be determined from the amount of light that it obscures. The discovery was confirmed by follow-up observations at the Keck observatory in Hawaii, which measured the effect of the orbiting planet on the spectrum of the parent star.


The most significant aspect of this discovery is that there is ‘significant evidence’, according to deputy science team leader Natalie Batalha, that the planet is rocky; other planets have been suspected of being rocky but there has always been significant doubt. 


Although 10b is rocky there is no chance that life could be supported there, as it is very close to its parent star, so close in fact that it completes a full orbit of the star in less than 1 day and has a surface temperature of almost 2000 K. 


Program scientist Douglas Hudgins claims “The discovery of Kepler 10b is a significant milestone in the search for planets similar to our own.” How long will it be before the first Earth mass planet is discovered?




Interested in learning more about planets outside the solar system? check out the astrobiology course at UCLan here:

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