There are thousands of young stars around the solar system, all sitting within a peculiar structure called the Local Bubble. Now, astronomers have discovered how they are linked. The creation of this vast bubble, a 1,000-light-year-wide void, is responsible for the formation of these young stars in the last 14 million years.
Published in the journal Nature, researchers reconstructed our corner of the Universe in 3D, discovering that all the young stars – and seven regions that are still actively star-forming – within 500 light-years of us sit on the surface of this bubble.
The simulation allowed researchers to turn back the clock 14 million years, to when over a dozen supernovae went off. These cosmic explosions propelled material, creating winds that swept up the interstellar medium into an extended shell. The fragments of the shell collapsed into molecular clouds, some of which formed young stars in the last several million years and others still creating new stars today.
"This is really an origin story; for the first time we can explain how all nearby star formation began," said astronomer and data visualization expert Catherine Zucker, from the Space Telescope Science Institute, said in a statement. "We've calculated that about 15 supernovae have gone off over millions of years to form the Local Bubble that we see today."
The expansion of the bubble has plateaued in terms of speed, but it continues to get bigger at a rate of 6.5 kilometers (4 miles) per second. This analysis was possible thanks to data from the European Space Agency’s Gaia observatory plus theoretical models.
"This is an incredible detective story, driven by both data and theory," said Harvard professor and Center for Astrophysics astronomer Alyssa Goodman, study co-author and founder of glue, data visualization software enabling the discovery. "We can piece together the history of star formation around us using a wide variety of independent clues: supernova models, stellar motions and exquisite new 3D maps of the material surrounding the Local Bubble."
The Solar System was not involved in any of those messy explosions and interstellar winds. It actually came into the picture later, only serendipitously ending up in the midst of it all.
"When the first supernovae that created the Local Bubble went off, our Sun was far away from the action," added co-author João Alves, a professor at the University of Vienna. "But about five million years ago, the Sun's path through the galaxy took it right into the bubble, and now the Sun sits – just by luck – almost right in the bubble's center."
The team plans to chart more of these bubbles and study the interactions between them and the rest of the galactic inhabitants. Understanding their evolution will provide insights into the connections between the death of stars and the birth of new ones.
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