* Astronomy

Ultracool Dwarf and the Seven Planets

Astronomers have found a system of seven Earth-sized planets just 40 light-years away. Using ground and space telescopes, including ESO's Very Large Telescope, the planets were all detected as they passed in front of their parent star, the ultracool dwarf star known as TRAPPIST-1. According to the paper appearing today in the journal Nature, three of the planets lie in the habitable zone and could harbour oceans of water on their surfaces, increasing the possibility that the star system could play host to life. This system has both the largest number of Earth-sized planets yet found and the largest number of worlds that could support liquid water on their surfaces.
Astronomers using the TRAPPIST-South telescope at ESO's La Silla Observatory, the Very Large Telescope (VLT) at Paranal and the NASA Spitzer Space Telescope, as well as other telescopes around the world, have now confirmed the existence of at least seven small planets orbiting the cool red dwarf star TRAPPIST-1. All the planets, labelled TRAPPIST-1b, c, d, e, f, g and h in order of increasing distance from their parent star, have sizes similar to Earth 
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Julien de Wit on the discovery of seven temperate, nearby worlds

Today, an international team including astronomers from MIT and the University of Liège in Belgium has announced the discovery of seven Earth-sized planets orbiting a nearby star just 39 light years from Earth. All seven planets appear to be rocky, and any one of them may harbor liquid water, as they are each within an area called the habitable zone, where temperatures are within a range suitable for sustaining liquid water on a planet's surface.
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Astronomers confirm TRAPPIST-1 is a single star and validate that its three transiting planets are Earth-size.

Interest in the recently-discovered TRAPPIST-1 with its three Earth-size planets is high. Astronomically speaking, at 40 light-years from Earth, the system is a hop, skip and a jump away. The star itself is a dim M-type star, which, relative to most stars, is very small and cool, but making transit detection of small planets easier.
Further detailed measurement of the planetary transits seen in TRAPPIST-1 will begin later this year when NASA's Kepler space telescope in its K2 mission will precisely monitor minute changes in the light emitted from the star for a period of about 75 days.
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