Nanodiamonds in Space

Extended Red Emission, or ERE, a mysterious astronomical effect in which regions of diffuse red light are observed in planetary nebulae and in the galactic halo, comes from nanodiamonds in space. So say Huan-Cheng Chang and his colleagues at the Academia Sinica in Taiwan. At this week's meeting of the American Astronomical Society in Washington, D.C., they reported the results of a recent experiment. As they suspected that ERE was analogous to the operation of a fluorescent lamp---where ultraviolet light is converted into visible light when it strikes a coating inside the lamp tube.

In the experiment, nanometer-sized diamonds, first filled with defects by hitting the diamonds with a powerful proton beam, then heated to a temperature of 800 degrees Celsius to create conditions roughly matching those of space. When yellow and blue light was shone on the nanodiamonds, ERE-type luminescence resulted. The diamonds presumably would have been made in the vicinity of carbon-rich stellar zones. One example of such emission, in the proto-planetary nebula HD 44179, also called "The Red Rectangle," can be seen here. Further discussion of the Red Rectangle was provided by Boston University astronomer Kenneth Brecher (see the Project LITE Web page).