The MEarth Project is delighted to announce the discovery of GJ1132b, a rocky planet 1.2 times the size of the Earth. GJ1132b transits a star that is both very small (1/5 the size of the Sun) and very nearby (only 39 lightyears away), making it much easier to observe than other known rocky planets. It provides the first opportunity for astronomers to study the atmosphere of a rocky planet outside the Solar System.
A paper describing this discovery appears in the 12 November 2015 issue of Nature magazine, and is summarized in a press release from the Harvard Center for Astrophysics. We make our PDF preprint of the paper available here.
Download the PDF
On 11 May 2015 (UT), one of the MEarth telescopes detected a slight dimming of the star GJ1132, caused by the planet passing in front and blocking the star's light. You can watch a time-lapse movie of the MEarth telescopes on this night, and see this discovery happen.
Watch the time-lapse movie
Astronomers know of thousands of transiting exoplanet, but few are as close as GJ1132b. We made the following animation to demonstrate the distances to known transiting planets, measured in lightyears (the distance light travels in one year).
Watch the animation
The MEarth Project is searching other nearby, small stars for more planets and studying the fundamental properties of low-mass stars in general. You can learn more about MEarth or access our public data on the MEarth webpage.
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