Astronomers Discover Sun was 'Feisty' in Infancy by Studying Young, Fiery Star

Astronomers have long wondered about the origins of our universe. They've studied stars and planets, hoping to glean information that would tell them a bit more about our ancient past. Now, they may have found something--at least when it comes to our own sun. They've discovered that the sun may have been active and "feisty" in its infancy, growing in fits and starts while burping bursts of X-rays.

In order to learn about the history of our sun, researchers studied the young star TW Hydrae, located about 190 light-years from Earth. This star can be found in the southern constellation Hydra the Water Snake. An orange, Type K star, TW Hydrae weighs about 80 percent as much as our sun and is only about 10 million years old. It's still accreting gas from a surrounding disk of material, which means that it's still "growing."

In fact, the star actually "eats" gas from the disk surrounding it. Yet the disk doesn't extend all the way to the star's surface, which means that TW Hydrae can't dine from it directly. Instead, infalling gas is funneled along magnetic field lines to the star's poles. By studying this phenomenon, the researchers learned more about the formation process in detail.

"By gathering data in multiple wavelengths, we followed the gas all the way down," said Nancy Brickhouse of the Harvard-Smithsonian Center for Astrophysics in a news release. "We traced the whole accretion process for the first time."

The infalling material actually smashes into the star, creating a shock wave and heating the accreting gas to temperatures that are greater than five million degrees Fahrenheit. The gas eventually cools as it moves inward and shifts to optical wavelengths of light. Yet this particular accretion is clumpy and episodic when building a star. In fact, at one point the amount of material landing on the star changed by a factor of five over the course of a few days.

The changes, while surprising, aren't the only thing that the astronomers found. They also noticed that some of the infalling material is pushed away in a stellar wind much like the solar wind that fills our solar system. Some is even channeled into giant loops and stellar prominences.

The findings could tell the researchers a little bit more about the origins of our own sun. While astronomers have known that young stars are much more magnetically active, they now also know about the interplay between the star's magnetic fields and the protoplanetary disk surrounding it.