A Cool Brown Dwarf

Today, as the New Hampshire windchill dipped below zero, making it one of the coldest days this winter, there is a new report about the, potentially, coolest sub-stellar object yet found outside our solar system. It is a brown dwarf, called SDSS1416+13B, with a temperature of approximately 200 degrees Celsius (or 400 degrees Fahrenheit).

A brown dwarf is an object of too low a mass to become a star, but is larger in mass than a gas giant, like Jupiter. Because brown dwarfs are typically quite cold, they are hard to detect, but it is easier to find them when scientists observe their infrared wavelengths. It was thus that SDSS1416+13B was found using the United Kingdom Infrared Telescope (UKIRT), located in Hawaii.

What is particularly interesting to scientists is the colorful nature of the brown dwarf. Peculiarly, the object's color changes from blue to red, depending upon which part of the spectrum it is observed in. Normally, such a cool object as a brown dwarf appears red. This differentiation in color may be a result of SDSS1416+13B's methane and water vapor atmosphere, which absorbs some of the infrared wavelengths and lets other infrared wavelengths pass through.

SDSS1416+13B orbits around another cool brown dwarf, named SDSS1416+13A, and it was discovered that these two are binary, meaning that they orbit around one another. Also, they are about fifteen to fifty light years away from us, which is relatively close considering that the Milky Way is 100,000 light years across.

More from Discover Magazine's Bad Astronomy blog.