The universe still keeps many secrets that the human being has not been able to reveal; among them, one that catches us very closely: how did our solar system come about? Of course, there are theories that try to answer this question, and the most settled among them explains that our cosmic environment had its origin, billions of years ago, in a supernova.
However, a team of researchers from the University of Chicago (USA) has just proposed an alternative theory. According to the new scenario proposed by his study, recently published in the Astrophysical Journal , our solar system would have emerged in a bubble driven by the wind around a giant star, long dead.
This star belongs to a type called Wolf-Rayet, with a size between forty and fifty times that of our Sun, hot -with temperatures on its surface between 25,000 and 50,000 degrees Kelvin- and suffering large losses of mass that are thrown out of the surface due to the violence of the intense stellar winds. And as the Wolf-Rayet star ejects those tons of elements from its surface, the stellar wind injects that material that was around it into bubble structures that have a higher density coating.
“The shell of a bubble of this type is a good place to produce stars,” as dust and gas get trapped inside, where they can condense into stars, according to study co-author Nicolas Dauphas, a professor at the Department of Geophysical Sciences.
Explain the origin of other similar stars
Following this hypothesis, the authors of the research consider that between 1% and 16% of all stars that are similar to the Sun could have formed in “stellar nurseries” – as they have called them – of that class.
The new configuration they propose from the University of Chicago comes to differ from the supernova hypothesis to make sense of two isotopes that appear in different proportions in our solar system compared to the rest of the galaxy.
On the one hand, the meteorites that remained from the early solar system tell us that there was a lot of aluminum-26; and studies, including one from Dauphas itself dating from 2015, increasingly suggest that there was less iron-60 isotope. Something that is puzzling for scientists, since supernovae produce both elements in large quantities.
“This raises the question of why one was injected into the solar system and the other not,” explains Vikram Dwarkadas, co-author and associate professor of research in Astronomy and Astrophysics. And this idea led them straight to the Wolf-Rayet stars, who cast lots of aluminum-26, but not iron-60.
And what happened to that giant star? He would have died a long time ago, and quite possibly his days would have come to an end as a supernova or collapsing into a black hole, which barely emits iron-60.