The combination of variables dictating star formation and evolution are more complex and less constant than researchers thought. Photo by NASA/UPI |
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May 1 (UPI) -- Astronomers thought they had discovered a reliable and consistent relationship between the size of stars and the mass of star-forming clouds of dust and gas, but new research has undermined the assumptions of several star formation theories.
Surveys of the Milky Way have revealed a strong correlation between the size and mass of star-forming cores and the size and mass of the mature stars. Astronomers have also identified a constant distribution of stellar masses across the Milky Way -- a bell curve, with extremely small and extremely large stars as the rarest, bookending the meat of the curve, and solar-mass stars, stars roughly the size and mass of the sun, as the most common.
Scientists weren't sure, however, if these constants were the same in other star-forming regions. New research suggests they're not.
When researchers used the ALMA telescope to survey a distant star-forming region named W43-MM1, situated 18,000 light-years away, they discovered a stellar mass distribution pattern very different from the Milky Way's.
In the Milky Way, stars with masses slightly smaller than the sun's are very common. In W43-MM1, they're rare. W43-MM1 also hosts an abundance of extremely massive stars, stars that are much less common in the Milky Way.
The new findings -- published this week in the journal Nature Astronomy -- suggest many of constants astronomers believed to govern stellar formation and evolution are not universal.
"These findings were a complete surprise and call into question the intricate relationship between the masses of star-forming cores and the masses of the stars themselves, which has long been assumed," Kenneth Marsh, an astronomer at Cardiff University in Wales, said in a news release.
"As a consequence, the community may need to revisit its calculations regarding the complex processes that dictate how stars are born," Marsh said. "The evolution of a core into a star involves many different physical interactions, and the results of studies such as this should help us better understand how it all happens."
