Astronomers Discover Young Star Had Explosive Growth in Milky Way Galaxy

Star birth is a somewhat inexact science. These brilliant bodies are formed when a large cloud of gas and dust condenses and eventually becomes so dense that it collapses into a ball. The pressure heats the matter and creates a glowing gas ball, creating a new star. Now, though, astronomers have discovered a young, newly formed star in the Milky Way that had such explosive growth that it was initially about 100 times brighter than it is now.

The new star was formed just within the past 100,000 years in our own galaxy. It was first spotted with the large international telescope, the Atacama Large Millimeter Array (ALMA). The findings actually give astronomers a much closer view of what happens during star formation.

"We studied the chemistry of the gas and dust cloud surrounding the early protostar (an early stage of star formation)," said Jes Jorgensen, one of the researchers, in a news release. "In this dense cloud, a chemical reaction takes place that enables the formation of several kinds of complex molecules, including methanol. One would expect that all of the molecules would be near the star, but with one of them we saw a clear ring structure. Something had removed a certain molecule, HCO+, from a wide area around the protostar."

During the star formation process, the dust and gas cloud is at first extremely cold. Simple molecules such as carbon monoxide and water settle on these grains of dust and solidify into ice. Where the molecules are close to each other, they bond together to form more complex molecules such as methanol, ethanol and simple sugars. The gravity of this early protostar then attracts much of the surrounding gas and dust cloud and when the material falls close to the young star, it slows down and the energy is converted into heat. The heat melts the ice, which then turns into water vapor.

"From the area where the HCO+ molecule has been dissolved by water vapor we can now calculate how bright the young star has been," said Jorgensen in a news release. "It turns out that the area is much greater than expected compared to the star's current brightness. The protostar has been up to 100 times brighter than the star is now."

The findings reveal a little bit more about the growth that a young star endures during its early formation process. This, in turn, can help inform future studies of other stars. Currently, the scientists are investigating whether this is a common phenomenon or if it's unique to this particular star.

The findings are published in the journal Astrophysical Journal Letters.