Oh, to be a Star!

ArtistÂs idea of brown dwarf OTS44 with its rotating planetary disk.

No matter how hard it tries, little OTS44 just doesn’t have what it takes to become a star. Although it’s too big and hot to be called a planet anymore, it’s still not big enough to light the nuclear fires of stardom. Instead, it’s an odd gas ball called a brown dwarf.

Using the Spitzer Space Telescope, astronomers recently discovered OTS44. They are excited, because it is by far the smallest brown dwarf they have ever seen at the center of a disk of dust that could someday become planets and form a solar system. Brown dwarfs are themselves not much bigger than planets. They are often seen orbiting their own stars. But sometimes brown dwarfs act like stars themselves and have planets or planet-forming disks of dust and gas around them.

The disk swirling around OTS44 has enough ingredients to eventually make a small gas giant planet (perhaps like Saturn or Jupiter), plus a few rocky Earth-sized planets. But the brown dwarf itself may be unlikely to provide enough warmth to support life on any of its planets.

Although brown dwarfs glow, they are very cool and dim compared to stars. Most of the light they put out, called infrared light, is invisible to ordinary telescopes. We cannot see infrared light, but we can feel it as heat. The Spitzer Space Telescope, however, is no ordinary telescope. It is designed especially to detect infrared light. It was launched in 2003 in an orbit around the Sun, trailing quite a distance behind Earth. The telescope is kept very, very cold so that whatever infrared light it detects must be coming from space, and not from the telescope itself.

Find out more about the remarkable Spitzer Space Telescope, and see what ordinary objects would look like if you could see them in infrared light. Go to the Infrared Photo Album at spaceplace.nasa.gov/en/kids/sirtf1/sirtf_action.shtml.