Illustration of a brown dwarf star, based on the star WISE J085510.83-071442.5, which is the coldest known brown dwarf and is located 7.2 light-years from Earth. The Sun is the bright star directly to the right of the brown dwarf. Brown dwarfs are dim star-like bodies that lack the mass to burn nuclear fuel as stars do. The temperature of WISE J085510.83-071442.5 is between minus 48 to minus 13 degrees Celsius. The colour of the brown dwarf in this illustration is arbitrary; it would have different colours when viewed in different wavelength ranges.