Family's grammar loss provokes debate.

When massive stars die, they often go out with a bang. Erupting in giant explosions called supernovas, these behemoths litter the cosmos with carbon, oxygen, and heavier elements.

A new study now suggests that supernova activity may help solve a longstanding puzzle: the abundance in the solar system and throughout the galaxy of three low-mass elements -- lithium, beryllium, and boron.

Astronomers have tried for years to account for the mix of these elements in the solar neighborhood, but their attempts have proved fruitless. For instance, they long ago abandoned the notion that nucleosynthesis, the fusion of light nuclei to make heavier atoms at a star's core, could generate the elements. That's because the burning of the lightest nuclei -- hydrogen and helium -- synthesizes the more massive elements, skipping the formation of lithium, beryllium, and boron.

An alternative proposal -- that lithium, beryllium, and boron are simply debris from the crash of cosmic rays into heavy nuclei in the interstellar medium -- has fared somewhat better.

The shattered nuclei presumably would form the trio of elements; however, calculations show that this process alone wouldn't generate atoms in the observed pattern. The collisions would produce twice the measured ratio of boron to beryllium and only half the observed abundance of boron-11 to boron-10.

Now, a recent discovery suggests a second source for the elements. Last year, Hans Bloemen of Space Research Leiden in the Netherlands and his colleagues used data from NASA's Compton Gamma Ray Observatory to identify a series of intriguing, broad emission lines coming from Orion, the closest stellar nursery to Earth. Their report sparked a French research group to propose a new and promising explanation for the abundance of lithium, beryllium, and boron in the sun's vicinity.

Michel Casse and Roland Lehoucq of the Centre d'Etudes de Saclay in Gif-sur-Yvette and Elisabeth Vangioni-Flam of the Institute of Astrophysics in Paris detail their work in the Jan. 26 NATURE.

The gamma-ray emissions indicate that the stream of low-energy carbon and oxygen nuclei coming from the direction of Orion is 30 times more intense than the stream detected near the sun. Casse and his colleagues calculate that when these low-energy particles collide with lighter cosmic rays, they form the trio of elements in the observed abundances.

The team notes that Orion, like many other star-forming regions, has experienced supernova activity recently. These exploded stars provide the enhanced emissions of low-energy carbon and oxygen nuclei in Orion, the researchers assert.

Alastair G.W Cameron of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., notes that to contribute to the mix of these elements near the sun and elsewhere in the galaxy, the same process should occur in star-birthing regions throughout the Milky Way. The trio of elements would then have enriched the cloud of dust and gas from which the solar system emerged.

"This is one piece of the puzzle in understanding how the solar system formed," Cameron says.