A group of stars is throwing international scientists into a tizzy. Current methods of dating stars simply will not work, leaving scientists baffled about their age.
What the Stars Are Revealing
On Friday, an international team of scientists, led by Cristina Chiappini of the Leibniz Institute for Astrophysics Potsdam, released a report detailing the discovery of a group of red giants that confused the team: the red giants’s “chemical clock” was off. That is, the chemical signature given off by the stars infers that they are old. But when the scientists cross checked that finding with astroseismology, that method suggested the stars were young, throwing standard models of the chemical evolution of our galaxy off kilter.
The team explained in the report the discrepancy between the tried and true chemical clock method and the newer method of astroseismology. The old ways of inferring the history of stars and planets is called “Galactic Archaeology”, which uses chemical signatures and bodily motions to determine age and activity. When stars explode, they release certain “alpha elements” such as oxygen into space for a short amount of time, afterward releasing elements such as iron. The time delay between these two actions allows scientists to infer the age of a star and is called the chemical clock. Using this method, the newly discovered group of red giants seemed old.
Astroseismology is a newer method to more accurately define the ages of stars using pulsation frequencies. Under this method, the red giants seemed young, despite being enriched with alpha elements. Chiappini and her team concluded the report by noting that the chemical clock method may not be as sure fire as scientists had once believed. Chiappini explained that though stars that could not be dated accurately with the chemical clock method had been seen before, but so few and far between that not much attention was given to them. This is the first instance of a cluster of stars undateable by the chemical clock method, allowing for scientists to compare the stars and perhaps parse out a more consistently accurate method.
These stars were found more toward the inner galactic disc regions, an area with interesting interactions between the bar and spiral arms which may be creating a more complex situation.
Check out the night sky light up in “Rhythm and Booms,” almost like stars in the galaxy: