NASA's WISE (Wide-field Infrared Survey Explorer) mission has discovered the coolest star-like objects yet - literally. Dubbed "Y dwarfs," these celestial bodies have temperatures that can be as cool as that of a human body. The coldest one discovered so far has a temperature of less than 80 degrees Fahrenheit.
Y dwarfs are technically a subclass of the brown dwarf category and are nearly impossible to see with visible-light telescopes.
WISE uses infrared, allowing astronomers to confirm the Y dwarfs' existence after 10 years of looking. The telescope spotted six of the dark objects within a distance of 40 light-years of our sun.
Brown dwarfs are sometimes referred to as failed stars, because they start out like stars but never accumulate enough mass at their cores to start the reactions that allow them to shine. Instead, they cool off over time and give off most of their light in infrared wavelengths.
The study of brown dwarfs helps astronomers understand how stars form and tells them more about the atmospheres of planets outside our solar system. Brown dwarfs have atmospheres similar to those of gas giant planets, but they are easier to observe because they're away from the light of a brighter star.
WISE data has exposed 100 new brown dwarfs so far, six of which are classified as Y dwarfs. Scientists expect more discoveries as they continue to examine the data coming in from the telescope.