Article Posted on : - Aug 24, 2011

This artist's conception illustrates what a "Y dwarf" might look like. Y dwarfs are the coldest star-like bodies known, with temperatures that can be even cooler than the human body. Photo: NASA/JPL-Caltech.

WASHINGTON (BNS): Scientists using data from NASA's Wide-field Infrared Survey Explorer (WISE) have discovered the coldest class of star-like bodies, with temperatures as cool as the human body.

WISE's infrared vision allowed the telescope to spot the faint glow of six Y dwarfs relatively close to the sun, within a distance of about 40 light-years, according to a news report by NASA.

"WISE scanned the entire sky for these and other objects, and was able to spot their feeble light with its highly sensitive infrared vision. They are 5,000 times brighter at the longer infrared wavelengths WISE observed from space than those observable from the ground," on Morse, Astrophysics Division director at NASA Headquarters in Washington, was quoted as saying in the report.

The Y's are the coldest members of the brown dwarf family. Brown dwarfs are sometimes referred to as "failed" stars. They are 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 at infrared wavelengths.

The telescope performed the most advanced survey of the sky at infrared wavelengths to date, from Jan. 2010 to Feb. 2011, scanning the entire sky about 1.5 times.

Of the 100 brown dwarfs, six are classified as cool Y's. One of the Y dwarfs, called WISE 1828+2650, is the record holder for the coldest brown dwarf with an estimated atmospheric temperature cooler than room temperature, or less than 80 degrees Fahrenheit (25 degrees Celsius), the news report added.

"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, California.

The Y dwarfs are between 9 and 40 light years from the sun. NASA said it is still processing and examining WISE's data.