Older stars don't slow down quite as much as previously thought, forcing researchers to rethink gyrochronology models. File Photo courtesy of NASA
WASHINGTON, Jan. 4 (UPI) -- As stars age, their rotations slow. By modeling this process, researchers have been able to accurately estimate the age of stars. The dating strategy is called gyrochronology.
New research suggests gyrochronology models require recalibration, as the spin rates of aging stars don't slow as much as previously thought.
Stars expel mass in the form of stellar wind. This wind reacts with the star's surrounding magnetic field, acting as a braking system on the star's rotational spin. But scientists at the Carnegie Institution for Science say older stars don't slow down quite as much as they thought. Researchers believe the change in deceleration is precipitated by a shift in the behavior of the star's aging magnetic field.
More than just requiring recalibration of models, the paper's results -- published this week in the journal Nature -- suggest Earth's sun may soon experience a change in its magnetic field.
Any shift would be gradual, but scientists are still trying to work out the time scale for a change in our sun's electromagnetic tendencies.
The necessary recalibrations aren't just important for our understanding of our own sun, but of stellar evolution more broadly.
"The ability to determine a star's age is important for improving our understanding of the life cycles of astronomical systems -- for cataloging how the star and the objects near it have changed through history and for predicting how they might change in the future," study author Jennifer van Saders, Carnegie astronomer, said in a press release. "Gyrochronology has the potential to be a very precise method for determining the ages of the average sun-like star, provided we can get the calibrations correct."
"I think this is a very important result that will greatly improve our ability to understand the stellar aging process," added John Mulchaey, director of Carnegie Observatories.