August 19, 2009

Study: More stars exist than thought

Data from NASA's Galaxy Evolution Explorer spacecraft may force astronomers to discard the assumption that stars of certain sizes form in certain quantities.

For decades, astronomers have believed the proportion of small to big stars was fixed. For every star 20 or more times as massive as the sun, for example, there should be 500 stars with the sun's mass or less.

But that belief, based on years of research, has been shattered with data from the spacecraft's ultraviolet telescope. That data includes proof that small stars come in even bigger bundles than previously believed, NASA said. For example, in some places in the cosmos, about 2,000 low-mass stars may form for each massive star. The little stars were there all along, but masked by massive, brighter stars, scientists explained.

What this paper is showing is that some of the standard assumptions that we've had -- that the brightest stars tell you about the whole population of stars -- this doesn't seem to work, at least not in a constant way, said Gerhardt Meurer, a Johns Hopkins University research scientist who led the study.

The research was published in the April 10 issue of the Astrophysical Journal.