For the first time, the star-forming regions that surround our solar system have been mapped.
These regions appear to be located on the Local Bubble, a distorted surface 1000 light-years wide. The interior of the bubble, which houses the solar system, is essentially empty space. However, its shell is made up of cold gas and dust left over from exploding stars. This material is now generating new stars.
A team of astronomers led by the Harvard & Smithsonian Center for Astrophysics (CfA) has now mapped the Local Bubble with the greatest precision ever - and discovered that the Local Bubble was most likely carved out of the interstellar medium millions of years ago by a series of supernova explosions.
This is consistent with past research, but there is a sting in the tail: the still-expanding Local Bubble is responsible for regions of increased star formation near its perimeter.
"This is really an origin story; for the first time we can explain how all nearby star formation began," astronomer Catherine Zucker of the Space Telescope Science Institute, who conducted the research while at the CfA, said.
Through a combination of optical, radio, and X-ray astronomy, the Local Bubble was just recently identified in the 1970s and 1980s. Gradually, these scans and investigations revealed a vast region 10 times denser than the Milky Way galaxy's average interstellar medium.
This seemed a reasonable explanation for the Local Bubble because we know supernova can carve out cavities in space, sweeping up gas and dust as they expand outwards.
However, figuring out how and when was more difficult. For one thing, measuring the dimensions of a region of space when you're inside it is difficult; and measuring a void when surrounded by bright stars and other cosmic objects is even more difficult.
They achieved it, however, with the help of data from the European Space Agency's Gaia satellite, which precisely tracks the positions, distances, and motions of stars. This enabled them to create a three-dimensional map of the various star-forming areas. The map also made use of Gaia's motion data to show how the Local Bubble has developed over time and how star-forming regions have formed.
When some stars near the end of their lives, they produce a massive explosion known as a supernova. Our Local Bubble appears to have developed when a series of supernova shock waves swept gas and dust through space, generating the dense shell of the Local Bubble. The shell began to generate a series of molecular clouds, which are the birthplaces of new stars, over time.
The research has been published in Nature.
