PLANETS THAT COULD BE HABITABLE...

The star, TRAPPIST-1, is about the size of Jupiter but is one thousand times dimmer than 

 our Sun and shines in the much cooler infrared part of the light spectrum.Orbiting it are

 three planets; two orbiting within 1.1 to 1.5 per cent of the distance  between the Earth 

and the Sun and passing in front of the star every one to two days.Because the star is so 

faint, so small and cold, it emits much less photons so these planets  should have 

temperatures which are quite similar to Venus.The planets were found almost by accident, 

as an international group of astronomers were  conducting a test survey of an ultra-cool 

dwarf star labelled TRAPPIST-1, which lies in the  constellation of Aquarius.Astronomers 

have discovered three planets orbiting the habitable zone of an ultra-cool  dwarf star just 

40 light-years from Earth.The discovery, reported today in Nature, is the first evidence 

supporting the hypothesis  that these very low-mass and low-temperature stars should

 have Earth-sized or smaller planets orbiting them.The planets, which are the size of 

Venus and Earth, are currently the best places to look  for life outside our solar system.