Our Solar System Could Have Formed in a Super-Hot Bubble
Out of the many mysteries we still have to figure out, our own solar system is one of them. It's currently assumed that the Sun formed from a supernova, which expells all the necessary building blocks to create a yellow dwarf star and its surrounding planets. But that might not be the case for us.
A new study from scientists at the University of Chicago claims that our solar system formed a different way: with bubbles. Giant, unimaginably hot bubbles created from giant, unimaginably hot stars, but bubbles all the same.
Some of the largest and most intensely hot stars in the galaxy are Wolf-Rayet stars, which are 40-50 times the size of our Sun and hundreds of times its mass. And when Wolf-Rayet stars are shedding their mass, this can combine with stellar winds to form dense bubble structures around them. Essentially, these bubbles act as a sort of incubation chamber for smaller stars, including (potentially) our own.
Wolf–Rayet star WR 31a surrounded by an expanding interstellar cloud of gas and dust (Hubble). pic.twitter.com/eJs222FurE— Andrew Rader (@marsrader) December 17, 2017
As for why they think our Sun likely formed this way, it comes down to isotopes that we can measure throughout the solar system. Our solar system is full of the isotope aluminum-26, which supernovas create a ton of during their explosion; but supernovas also create iron-60, which our solar system doesn't have as much of as other systems in the galaxy, suggesting a simple supernova wasn't responsible .
So if the problem is that a supernova creates both aluminum-26 and iron-60, and our solar system only has lots of aluminum-26, then what's something powerful enough to create a star and which only produces aluminum-26? This led them to Wolf-Rayet stars, which do just that.
According to Vikram Dwarkadas, a co-author on the study, that aluminum-26 is a centerpiece of this new solar-forming scenario. He said the following in a press release:
Once the shell of that super-bubble collapses, this is what eventually forms a solar system. There's a good chance that the potential Wolf-Rayet star which birthed our neighborhood is long gone, having collapsed entirely into a black hole lurking somewhere in the Milky Way. This too, would produce almost no iron-60, so even that fits with this scenario.
It could be a long time until we have a concrete answer regarding who our solar system's real parents are, but this certainly does answer some unexplained questions. Just don't expect us to go visiting our Wolf-Rayet father anytime soon.