All 468 stars in the Milky Way Stellar Stream Theia 456 are related – “It’s like finding a needle in a hurry”


An artistic rendering of generic stellar currents in the Milky Way. Credit: NASA / JPL-Caltech / R Injury, SSC and Caltech

Examination of the Thia 456 shows that about 500 of its stars were born at the same time.

Galaxy Homes 8,292 recently discovered stellar currents – all named Thia. But theia 456 is special.

A stellar current is a rare linear pattern – instead of a cluster – of stars. After combining several datasets captured by the Gaia Space Telescope, a team of astrophysicists discovered that all of the 468 stars of Thea 456 were born at the same time and are traveling in the same direction in the sky.

“Most stellar groups form together,” said Jeff Andrews, a Northwestern University Astronomer and team member. “The exciting thing about the Thia 456 is that it is not a small cluster of stars. It is long and long. There are relatively few streams that are nearby, young and therefore widely dispersed. “

Andrews presented the research during a virtual press briefing at the 237th meeting of the American Astronomical Society. “IIA 456: A New Stellar Union in Galactic Discs” took place on 15 January 2021 as part of “The Modern Milky Way” session.

Andrews is a postdoctoral fellow at Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). He did this with astrophysicists Marcel Agueros and Jason Curtis Columbia University, Julio Chaname of the Pontispa Universitated Catolica, Simon Scholler and Kevin Covey of the University of Tampa and Marina Konkel of Western Washington University.

While researchers have long known that stars are formed in groups, most known groups are spherical in shape. More recently astronomers have begun to find new patterns in the sky. They believe that the long strands of wire were once tightened, slowly separated and stretched by tidal forces.

“As we have begun to become more advanced in our instrumentation, our technology and our capacity for data, we have found that stumps exist in more structures than clamps,” Andrews said. “They often make these streams in the sky. Although we have known about these for decades, we are beginning to find hidden ones. ”

Pulling over 500 light-years, the Thia 456 is one of those hidden streams. Because it resides within the galactic plane of the Milky Way, it is easily lost within the background of a galaxy of 400 billion stars. Most stellar currents are found elsewhere in the universe – pointed away from the Milky Way by a telescope.

“We focus our telescopes in other directions because things are easier to find,” Andrews said. “Now we are starting to find these currents in the galaxy itself. It is like finding a needle in a histack. Or, in this case, the detection of a wave in an ocean. “

Identifying and examining these structures is a data science challenge. Artificial intelligence algorithms combed vast datasets of stellar data to find these structures. Andrews then developed an algorithm for cross-referencing data with an already existing catalog of iron abundance of documented stars.

Andrews and his team found that 468 stars within Thia 456 had similar iron abundances, which means that – 100 million years ago – stars were likely to have formed together. Adding further evidence to this discovery, the researchers examined a light curves dataset that describes how stars’ luminosity changes over time.

“We are starting to find these currents in the Milky Way galaxy itself. It is like finding a needle in a histack. Or, in this case, detecting a wave in an ocean ”- Jeff Andrews, Astronomer

“It can be used to measure how fast the stars are rotating,” Agueros said. “Same-age stars should show a different pattern in their spin rates.”

With the help of data from NASAFrom the exoplanet survey satellite and the Zwick transient facility – both of which produce light curves for stars in Thea 456 – Andrews and his colleagues were able to determine that the currents of the stars share a common age.

The team also found that the stars are moving in the same direction simultaneously.

“If you know how the stars are moving, you can fall behind to find out where the stars came from,” Andrews said. “As we turned the clock backwards, the stars became closer together. Therefore, we think that all these stars were born together and had a similar origin. “

Andrews stated that a combination of datasets and data mining is necessary to understand the universe around us.

“You can only get so far with one dataset,” he said. “When you combine datasets, you get a very rich sense of what happens in the sky.”

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