A billion years, give or take
New estimates of the sun’s life span may revise fundamental assumptions
The Borexino collaboration, a group of researchers including UMass physicist Andrea Pocar, recently reported detections of solar neutrinos that favor higher estimates of the sun’s metallicity, which has large implications for its temperature, life span and other properties. If their estimates prove correct, much of the underpinning of solar physics and astronomy could shift.
From Quantum Magazine:
In the coming years, the Borexino team expects to detect rare solar neutrinos produced in the CNO cycle, a fusion reaction in the sun in which carbon, nitrogen and oxygen atoms serve as catalysts for fusing hydrogen into helium. “The CNO neutrinos are greatly affected by metallicity, so measuring these neutrinos could be definitive,” said Andrea Pocar, a physicist at the University of Massachusetts Amherst and a member of the Borexino collaboration.
If it turns out that the sun is, in fact, only 1.3 percent metal, this would mean the standard solar model really does have opacity wrong. “This impacts essentially all of astronomy,” Asplund said, “since an accurate understanding of stellar evolution underpins almost everything we do.” Estimated ages of stars and galaxies would have to be revised by as much as 10 to 15 percent. Unfortunately for the sun itself (and future life on Earth), low-metallicity stars burn fuel faster than high-metallicity stars, so our sun would die about a billion years sooner than we thought.