June 5, 2013
NGC 6334: Shedding Light On Starburst Regions
John P. Millis, Ph.D. for redOrbit.com — Your Universe Online
Stars are formed in massive clouds of gas that are being compressed by some nearby event. Over time, the region will be consumed by the forming stars, leaving a cluster that will eventually drift apart. But what starts this process in the first place?
Often these regions of star formations -- known as starburst regions -- are found in distant galaxies where the activity level is very high. But this presents a problem: because of the great distance, identifying smaller stars is difficult. And these low mass stars are an important piece to the puzzle.
To get a better idea about the true stellar population of the starburst regions, and to perhaps even gain insight into what types of events trigger the rapid star formation, researchers look to regions of the Milky Way galaxy that might be undergoing a similar process.
A team from Iowa State University and the National Optical Astronomy Observatory (NOAO) have completed the most detailed study of nearby starburst region NGC 6334 (or Cat´s Paw Nebula) — a gas rich region of our galaxy about 5,500 light-years away in the constellation Scorpius. Filled with hot, massive stars, the nebula has been previously studied at great length. However, prior work focused on these heavier stars, had not revealed the same level of detail about smaller stars that may exist in the region.
Team leader, and Iowa State graduate student Sarah Willis, used the NOAO Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory, Chile, and the Spitzer Space Telescope, to image the lower mass stars in the cloud.
Willis and her collaborators were able to catalog the stellar population down to stars about the size of our Sun. Then, using stellar census data, they were able to estimate the number of stars with even lower mass that exist in the system. Essentially, they were able to draw on formation rates of how many low mass stars form for every Sun-like star that exists.
The result is that about 3,600 solar masses worth of gas is being converted to stars every million years. This is higher than expected, and if taken to be a good model for starburst regions, could indicate that distant starburst regions are even more active than previously thought.