They are, nevertheless, heated during their formation by gravitational contraction but then continuously cool as this energy is radiated away. The chances of identifying a rare object like this in such a restricted area are very small and the astronomers readily admit that they must have been very lucky. It also demonstrates the power of modern observational techniques. The observed sky area measures only 2.3 x 2.3 arcmin 2 and is referred to as the NTT Deep Field . The field measures 1.3 x 1.3 arcmin 2 .
North is up and East is left.
The astronomers noted a star-like object of extreme colour in this field. It seemed that there were only two possibilities. Whatever its nature, this was obviously a most interesting object. Despite its faintness, initial observations with SOFI at the NTT covering the infrared J and H-bands already revealed some of the molecular absorptions characteristic of methane brown dwarfs. Unlike Gliese 229B , however, it does not appear to be a member of a binary system.