Astronomers say these failed stars are not as prevalent as thought

Jun 9, 2012 09:40 GMT  ·  By

According to the conclusions of a study conducted using the NASA Wide-field Infrared Survey Explorer (WISE), it would appear that the solar neighborhood contains fewer failed stars called brown dwarfs than originally suspected.

Brown dwarfs are celestial bodies that blur the distinction between stars and gas giants. They are believed to have formed from insufficiently-large clouds of hydrogen gas, which failed to ignite properly when they collapsed.

As such, they are barely heated to a few hundred degrees, and are of relatively small size. Brown dwarfs can be relatively difficult to detect, but not to sensitive telescopes such as WISE.

What is interesting about the new discovery is that the solar neighborhood was at first thought to be a more crowded place. Now, it would appear that the area around the Sun is a little less interesting than researchers were led to believe.

“This is a really illuminating result. Now that we're finally seeing the solar neighborhood with keener, infrared vision, the little guys aren't as prevalent as we once thought,” expert Davy Kirkpatrick says.

He is a member of the WISE science team, and is based at the California Institute of Technology's (Caltech) NASA Infrared Processing and Analysis Center (IPAC). Kirkpatrick says that scientists were expecting to find one brown dwarf for each star around the Sun.

However, WISE revealed the existence of one brown dwarf for each star in the solar neighborhood. The new data will now be used to refine our estimates of how many brown dwarfs may exist in the Milky Way, and other galaxies.

“We think [that brown dwarfs] can form by several different mechanisms, including having their growth stunted by a variety of factors that prevent them from becoming full-blown stars. Still, we don't know exactly how this process works,” Kirkpatrick adds.

The WISE spacecraft, which has since been turned off, launched back in 2009, and analyzed the night sky throughout 2010, surveying the entire infrared Universe one and a half times. During this time, it studied some of the coldest objects in space.

During its mission, it also managed to identify a few near-Earth objects (NEO), and calculate the danger they pose to our planet.