Why It’s So Difficult For Scientists To Measure The Age Of Stars

One potential way to determine a star’s age is to look at the speed at which it rotates. When stars are born, they rotate very quickly, but over time they slow down. This happens because the star gives off charged particles, called stellar winds, which interact with the magnetic field. As these two interact, they cause the star to gradually slow rotation in an effect called “magnetic braking.”

The effect isn’t simple, though. A star that spins very fast will have a strong magnetic field, and it will slow down faster. However, over time stars tend to follow a similar evolution, so by the time a star is one billion years old, it will spin at around the same rate as other stars of a similar mass and a similar age.

This means that if scientists can measure both the rotation speed and the mass of a star, they can estimate its age. To measure rotation, they look at dips in brightness caused by cooler regions on a star called star spots (like sun spots on our sun).

Scientists, like Zachary Claytor from the University of Florida, are working on a program to identify a star’s rotation time using AI. First, they had to train a neural network on simulated data, so it can analyze real data in the future. “This program lets the user set a number of variables, like the star’s rotation rate, the number of spots, and spot lifetimes,” Claytor explained. “Then it will calculate how spots emerge, evolve, and decay as the star rotates and convert that spot evolution to a light curve — what we would measure from a distance.”