The age of the sun may be distorted by its magnetic activity, research claims
Astronomers have traditionally relied on helioseismology to estimate the age of the sun by analyzing the vibrations that ripple through its interior. Recent research, however, has revealed a major hurdle: the sun’s magnetic activity, which follows an 11-year cycle, appears to be distorting these measurements. Data from the Birmingham Solar Oscillations Network (BISON) and NASA’s SOHO mission, which lasts more than 26.5 years, revealed a 6.5 percent difference in the sun’s age when measured at solar minimum compared to solar maximum.
This discrepancy, attributed to variations in the Sun’s magnetic activity, suggests that similar methods used to measure the ages of other stars may also be affected, particularly those with more intense magnetic fields.
How Magnetic Activity Changes the Perception of the Solar Age
The Sun’s magnetic activity, which alternates between solar minimum and maximum, is more influential than previously thought, a study finds paper published in the journal Astronomy & Astrophysics. During periods of high magnetic activity, the oscillations in the Sun detected by instruments such as BISON and GOLF (Global Oscillations at Low Frequency) produce results that indicate a younger Sun than during periods of low magnetic activity.
These oscillations, caused by internal waves in the Sun, alter the luminosity and surface motions, allowing scientists to infer details about the Sun’s internal structure and, theoretically, its age. However, the unexpected influence of magnetic activity on these measurements challenges the long-held assumption that such activity would have little impact on helioseismology.
Challenges for future stellar observations
The implications of this discovery extend beyond our Sun. As scientists prepare for the European Space Agency’s upcoming PLATO mission, set to launch in 2026, they must now consider the impact of magnetic activity when measuring the ages, masses and radii of distant stars. PLATO aims to detect dips in starlight caused by both passing exoplanets and asteroseismic oscillations similar to those observed in the Sun.
If magnetic activity significantly alters these measurements, as seen with the Sun, it could necessitate a reevaluation of previous data from missions such as NASA’s Kepler Space Telescope. This revelation poses a “looming challenge” for the future of asteroseismology, which will require new methods to ensure accurate measurements of stellar ages, particularly for more magnetically active stars.
