NASA's Spitzer Space Telescope detected a prebiotic, or potentially
life-forming, molecule called hydrogen cyanide (HCN) in the planet-forming
disks around yellow stars like our sun, but not in the disks around
cooler, reddish stars.
The observations are plotted in this graph, called a spectrum, in which
light from the gas in the disks around the stars has been split up into
its basic components, or wavelengths. Data from stars like our sun are
yellow, and data from cool stars are orange. Light wavelengths are shown
on the X-axis, and the relative brightness of disk emission is shown on
the Y-axis. The signature of a baseline molecule, called acetylene (C2H2),
was seen for both types of stars, but hydrogen cyanide was seen only
around stars like our sun.
Hydrogen cyanide is an organic, nitrogen-containing molecule. Five
hydrogen cyanide molecules can link up to form adenine, one of the four
chemical bases of DNA.