The Earth sits in a void 1,000 light-years across, a kind of cosmic bubble that is surrounded by a layer of cooler, denser neutral gas and dust. Researchers have long wondered what created this “superbubble.” Now, A study suggests that at least 15 powerful stellar explosions inflated this cosmic bubble.
It’s called the Local Bubble, and precisely how and why it came to exist, with the Solar System floating in the middle, has been a challenge to explain. In a new paper appearing in Nature, the researchers describe it as “a cavity of low-density, high-temperature plasma surrounded by a layer of cool, neutral gas and dust.”
A team of astronomers from the Center for Astrophysics | Harvard & Smithsonian (CfA) and the Space Telescope Science Institute (STScI) reconstruct the evolutionary history of our galactic neighborhood, mapping the Local Bubble with the greatest precision to date. The analysis indicates that it probably formed after a series of supernova explosions that began 14 million years ago.
The Earth sits in a 1,000-light-year-wide void surrounded by thousands of young stars—but how did those stars form?
New research shows that a chain of events beginning 14 million years ago created a vast bubble, and triggered the formation of nearby, young stars. (1/5) pic.twitter.com/cc5KBHM1JO
— Hubble Space Telescope (@HubbleTelescope) January 12, 2022
“We find that almost all star-forming complexes in the solar neighborhood are located on the surface of the Local Bubble and that their young stars show outward expansion mainly perpendicular to the surface of the bubble,” the authors wrote in the article. “The traces of the movements of these young stars support a picture in which the origin of the local bubble was a burst of star birth and then death (supernovae) that took place near the center of the bubble approximately 14 million years ago” .
Astronomers first theorized that superbubbles were ubiquitous in the Milky Way almost half a century ago, but it was considered statistically highly unlikely that our solar system would be in one. Interestingly, it is located almost right in the center of the Local Bubble.
We know that supernovae can carry gas and dust with them as they expand outward. Those stellar explosions expel the materials, such as hydrogen gas, needed to create new stars. This is something we can naturally think of to explain the mystery, but pinpointing the dimensions and when it happened is a very complex job. It is doubly difficult, since it is a question of measuring a void being inside it and that it is surrounded by bright stars. Understanding this gives us valuable information about the origin of nearby stars.
Alyssa Goodman, a Harvard professor and co-author of the study, has compared the discovery to a Milky Way that resembles Swiss cheese with many holes, which are ejected by supernovae, and new stars can form in the cheese around the holes created. for the dying stars.
“This is really an origin story; for the first time we can explain how the formation of nearby stars began,” said astronomer and data visualization expert Catherine Zucker.
A 3D space-time animationreveals that all young stars and star-forming regions within 500 light-years of Earth sit on the surface of the giant bubble we have described.
The research has been published in Nature.
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