Local bubble: huge gas structure containing the solar system mapped for the first time

The solar system sits inside a structure called the Local Bubble which is around 1,000 light-years in diameter – and a map of its surface shows it to be the site of star formation

Space


January 12, 2022


Artist’s rendering of the local bubble, with star formation on the surface of the bubble

Leah Hustak (STScI)

The star-forming regions that surround our solar system have been mapped for the first time.

These regions appear to lie on a distorted surface 1000 light-years in diameter, called a local bubble. The interior of the bubble, where the solar system is located, is mostly empty space. But its shell contains cold gas and dust, remnants of exploding stars. New stars are now forming from this material.

We’ve known about the existence of the local bubble — and the star-forming regions closest to the solar system — for decades. But Catherine Zucker of Harvard University and her colleagues have now established a clear link between the two.

They did this using data from the European Space Agency’s Gaia satellite, which maps the positions, distances and motions of stars with great precision. This allowed them to build a three-dimensional map of the different star-forming regions. The map also used Gaia’s motion data to plot the evolution of the local bubble over time and create the star forming regions.

“We discovered a common origin for all nearby star formations,” says Zucker. “We can basically explain how every region of star formation within 500 light-years of our sun began.”

When certain stars reach the end of their life, they trigger a powerful explosion called a supernova. Our local bubble appears to have formed when multiple supernova shock waves swept gas and dust through space, forming the dense shell of the local bubble. Over time, the shell began to form a series of molecular clouds, which are the cradles of new stars.

“This result makes a strong case that star formation triggered by shell expansion is probably more important than we previously thought,” says Martin Krause of the University of Hertfordshire, UK.

Zucker and his team are confident, within a margin of error, about the shape of the bubble where the star forming regions are, but other parts of the bubble shape are less certain.

Journal reference: NatureDOI: 10.1038/s41586-021-04286-5

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Arline J. Mercier