Astronomers have discovered 6 Y dwarfs approximately 40 light-years away from the sun.
The dark orbs, which are categorized as the coldest class of star-like bodies, were tracked down by NASA's WISE infrared telescope.
"WISE scanned the entire sky for these and other objects, and was able to spot their feeble light with its highly sensitive infrared vision," explained Jon Morse, Astrophysics Division director at NASA Headquarters in Washington.
"They are 5,000 times brighter at the longer infrared wavelengths WISE observed from space than those observable from the ground."
According to Morse, the Y's are the coldest members of the brown dwarf family, which are sometimes referred to as "failed" stars.
They are simply too low in mass to fuse atoms at their cores - and thus don't burn with the fires that keep stars like our sun shining steadily for billions of years.
Instead, these objects cool and fade with time, until what little light they do emit is "visible" only at infrared wavelengths.
NASA astronomers are keen to study brown dwarfs, as they can help scientists better understand how stars form, while providing additional data about the atmospheres of planets beyond our solar system.
For example, the atmospheres of brown dwarfs are similar to those of gas-giant planets like Jupiter, but are easier to observe because they are alone in space, well away from the blinding light of a parent star.
So far, WISE has detected 100 new brown dwarfs, with more discoveries expected as scientists continue to examine an enormous quantity of data from the telescope.
Of the 100 brown dwarfs, six are classified as cool Y's. One of the Y dwarfs, known as WISE 1828+2650, is the record holder for the coldest brown dwarf, with an estimated atmospheric temperature cooler than room temperature, or less than about 80 degrees Fahrenheit (25 degrees Celsius).
"The brown dwarfs we were turning up before this discovery were more like the temperature of your oven," said Davy Kirkpatrick, a WISE science team member at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, Calif.
"With the discovery of Y dwarfs, we've moved out of the kitchen and into the cooler parts of the house."