TRAPPIST, a 60cm telescope in Chile designed to detect planets round small red dwarfs via the transit method, found a jackpot. The ultracool dwarf star, 2MASS J23062928-0502285, now known as TRAPPIST-1, is thought to be about 80 Jupiter masses (1/13 of the mass of our sun) and about the same diameter as Jupiter; about half the temperature of our sun; about 1/2000 of the luminosity of our sun; and about 40 light years from here. It has 3 planets of size comparable to Earth with orbital periods 1.5 days, 2.4 days, and somewhere between 4 to 79 days. The two inner planets are almost certainly tidally locked with only 1 side exposed to sunlight. They receive about 4 and 2 times the irradiation as Earth and have about same size as Earth. Due to the tidal locking it seems certain the night side will be cold and the day side hot and therefore a large "belt" must exist on its surface with temperatures in the liquid water range. The outer planet's temperature is less clear since its orbit needs to be worked out, but it quite possibly also has temperatures within the liquid water range. The whole TRAPPIST system is miniature compared with our solar system, about 0.1% of its size, indeed is more like Jupiter & its moons in scale. This sort of star is the longest-lived kind of star and I would expect TRAPPIST-1 to have lifetime of about 1500 gigayears as opposed to 10 Gyr for our sun. If there is life on a planet orbiting this class of tiny star, it therefore would enjoy the longest possible time to evolve. http://www.eso.org/public/archives/releases/sciencepapers/eso1615/eso1615a.p... -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)