SOME of the first stars may not have been born alone, but as twins. If so, it could explain a long-standing mystery about our galaxy.
Computer simulations of the early universe suggest that the first stars to form were very large, about 300 times the mass of our sun. To investigate further, Matthew Turk of the Kavli Institute for Particle Astrophysics and Cosmology in Menlo Park, California, and colleagues ran five simulations of conditions 20 million years after the big bang, each with slightly different initial distributions of hydrogen and helium gas, for long enough for star-forming cores to condense out. One of the models showed a cloud had fragmented to form two such cores, possibly because the cloud’s spin had torn it apart ().
Many massive first stars should have blown apart in exotic explosions. Yet the telltale chemical signatures this should have left have not been observed in the ancient stars’ early descendants that roam our galaxy. If some of the first stars were twins, each might be too small to trigger such explosions.
Advertisement