Ever peer up at the sky at night and wonder where all those stars came from? Researchers at the Harvard-Smithsonian Center for Astrophysics and the Space Telescope Science Institute have discovered some fascinating answers on that front that should keep astronomers buzzing for light years to come.
In a statement Wednesday, the astrophysics center said the findings appear in a new article published in the science journal Nature.
The researchers, the statement said, undertook the herculean task of tracing the evolutionary history of “our galactic neighborhood,” demonstrating how events that began unfolding 14 million years ago led to the creation of a big bubble that’s “responsible for the formation of all nearby, young stars.”
The team’s 3-D spacetime animation technology showed all young stars and star-forming regions located within 500 light years of Earth rest on the surface of a giant mass dubbed the Local Bubble.
Astronomers, officials said, have known about the Local Bubble’s existence for decades, but scientists can now see and understand its beginnings and its impact on the gas around it.
Researchers next plan to map out more interstellar bubbles, which will “ultimately allow astronomers to understand the role played by dying stars in giving birth to new ones, and in the structure and evolution of galaxies like the Milky Way,” the statement said.
“This is an incredible detective story, driven by both data and theory,” said Harvard professor and Center for Astrophysics astronomer Alyssa Goodman, a study co-author, in the statement. “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 3-D maps of the material surrounding the Local Bubble.”
Catherine Zucker, who worked on the study during a fellowship at the astrophysics center, said the research is groundbreaking.
“This is really an origin story; for the first time we can explain how all nearby star formation began,” Zucker said in the statement.
In addition, Zucker, now a NASA Hubble fellow at the Space Telescope Science Institute, said researchers have traced the formation of the Local Bubble to multiple supernovae over a lengthy stretch of time.
“We’ve calculated that about 15 supernovae have gone off over millions of years to form the Local Bubble that we see today,” Zucker said in the statement.
Another study co-author, João Alves, a professor at the University of Vienna, also described the findings.
“When the first supernovae that created the Local Bubble went off, our Sun was far away from the action,” Alves said in the statement. “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 researchers also discussed their findings during a virtual briefing Wednesday with the American Astronomical Society.
“We’ve known about the Local Bubble for many, many decades,” Zucker said during the briefing. “There have been many studies published on it. But what we didn’t know is the relationship between the Local Bubble and nearby star formation.”
But now the details of that relationship are coming into focus — shining brightly, in a sense.
“The crux of this story is that we can now reconstruct the evolutionary history of our galactic neighborhood,” Zucker said. “Basically if we rewind the clock, we find that a chain of events beginning 14 million years ago with some powerful supernova explosions created this gigantic bubble with a surface that’s ripe for star formation.”
Narrating a powerpoint presentation with an artist rendering of the process, Zucker continued, “we see here, the supernova exploding. It’s inflating this bubble of gas. And as this bubble expands, it sweeps up clouds of gas and dust on its surface, sort of like a snowplow can sweep up snow.”
Zucker noted the “supernova exploding, setting off this shockwave. That shockwave sweeps up gas, and you can see, sort of on the edge of the bubble here, the purple here is the star-forming gas, and then the white sort of clusters, those are the young stars that are forming in the gas. And so both of those are being swept up by the expansion of this bubble.”