Astronomers examine for the first time, in high resolution, the huge region of the Milky Way forming stars

Astronomers from the United States and South Korea made the first high resolution radio telescope observations of molecular clouds in a massive star formation region of the outer Milky Way.

"This area is behind a cloud of dust and gas nearby," said Charles Kerton, an associate professor of physics and astronomy at Iowa State University and a member of the Iowa State University team. ;study. "The cloud blocks light, so we have to use infrared or radio observations to study it."

The Milky Way region is called CTB 102. It is about 14 000 light-years from Earth. It is classified as HII region, which means that it contains ionized – charged hydrogen atoms. And because of its distance from the Earth and the dust and gases that separate them, it has been difficult to study.

And so, "this area has been badly mapped," said Kerton.

Astronomers describe their first draft of a new high-resolution map for the region in an article recently accepted for publication in the Astrophysical Journal. The lead authors are Sung-ju Kang, scientific staff member of the Korean Institute of Astronomy and Space Science and former graduate student of Iowa State University; and Brandon Marshall, a former Iowa State graduate student who accepted a professorship at the University of Nebraska in Kearney. Other co-authors are Kerton and Youngsik Kim, Minho Choi and Miju Kang, both of the Korean Institute of Astronomy and Space Science. Kim is also a member of the Daejeon Observatory in South Korea.

Kerton said that astronomers had used a recently commissioned radio telescope at the Taastruk Radio Astronomy Observatory in South Korea to perform high-resolution carbon monoxide observations of the molecular clouds of the galactic region.

"It tells us the mass and structure of the material in the interstellar medium," said Kerton.

Astronomers have also compared their radio observations with existing infrared wide-field survey infrared data and the two-micron survey on all skies. The infrared data allowed them to classify the young stars forming in the molecular clouds of the region.

The data provides three main observations, report astronomers in their article.

First, astronomers have used radio data to describe the physical structure and features of the newly mapped molecular clouds of the region – they are large enough, about 180 light-years away and of equal mass about 100,000 masses of our sun. Then they used infrared data to determine the young stellar content in the clouds. Finally, they combined the two data streams to study the effectiveness of star formation in the galactic region.

They report that the effectiveness of star formation in the entire CTB 102 region is about 5% to 10%, which is similar to other giant molecular clouds in the galaxy. But they found a subregion of clouds with star formation efficiency of 17% to 37% (depending on the mass calculation of the subregion). This is much more than expected for a sub-region of this size. They assume that the sub-region is the site of a large group of young developing stars integrated into the molecular cloud.

Why all the star formation in this subregion? Kerton says that it is a question to be deepened. Perhaps, he said, the interstellar material of this subregion, which adjoins the huge HII region, is something special.

"It's our first look at all of this," Kerton said. "The oldest data contained only a few points, a few pixels, so we could not isolate this relatively small region of the galaxy."

But now they could – with the help of the new South Korean radio observatory.

The high-resolution observations of the study, Kerton said, "also show that the telescope is ideal for studying similar regions in our galaxy – there are many other potential targets."