A Spitzer Space Telescope image of a Brown Dwarf (?), Click for larger. Credit: NASA/JPL-Caltech/P. Eisenhardt (JPL)

This image shows what astronomers think is one of the coldest brown dwarfs discovered so far (red dot in middle of frame). The object, called SDWFS J143524.44+335334.6, is one of 14 such brown dwarfs found by NASA’s Spitzer Space Telescope using infrared light. Follow-up observations are required to nail down this “failed” star’s temperature, but rough estimates put this particular object at about 700 Kelvin (800 degrees Fahrenheit).

In this image, infrared light with a wavelength of 3.6 microns is color-coded blue; 4.5-micron light is red. The brown dwarf shows up prominently in red because methane is absorbing the 3.6-micron, or blue-coded, light.

The Spitzer Space telescope has found 14 brown dwarfs using its infrared vision.  The image shows (they think) one of coldest found so far, it’s the red star in the center of the image.  Cool in this case is only about 800 degrees, certainly no where near a true star.  It has a name too: SDWFS J143524.44+335334.6, catchy eh?  To be sure more observations will be necessary.

Brown dwarfs you will recall are essentially failed stars, they are small in terms of stellar mass and not hot enough to trigger the required thermonuclear reactions in their cores or if they manage a reaction they cannot sustain them.  Why?  Again they are too small and the heating creating by gravitational contraction just doesn’t make it.

Brown dwarfs are quite interesting objects.  They are pretty much invisible because they are cool and just don’t give off much light.  There is speculation that a brown dwarf might even be closer than the closest star to our sun, Proxima Centauri at 4.2 light-years.  If there is one, the WISE spacecraft will hopefully find it.

Visit the Spitzer website.