Was the star-forming Local Bubble created by a stellar explosion?
Earth is surrounded by a 1,000 lightyear-wide void, called the Local Bubble, the edge of which is marked by thousands of young stars. Now, thanks to new simulations, astronomers might finally know what caused it –a series of supernovae beginning 14 million years ago which pushed gas outwards, creating dense regions ripe for star formation.
Using observations from the Gaia observatory, astronomers could map out the bubble’s irregular shape and determined that it is drifting through the Galaxy at about 6.5km per second. The simulations used these two pieces of information to reveal that the bubble has been carved out by around 15 supernovae over millions of years.
“When the first supernovae that created the Local Bubble went off, our Sun was far away from the action,” says João Alves from the University of Vienna, who took part in the study. “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 centre.” https://hubblesite.org