Astronomers used NASA’s Chandra X-ray satellite to study four old red dwarf stars. Their observations revealed a low rate of X-ray emission. The discovery has implications for understanding how the magnetic field in our Sun and similar stars are generated.
Astronomers use X-rays as a proxy for the strength of a star’s magnetic field. The aforementioned stars are emitting X-rays at a low rate, an indication that their magnetic field is weak. Scientists know that young stars, regardless of their mass, have very high levels of X-ray emission and therefore strong magnetic fields. This new discovery may indicate that magnetic fields weaken over time. This is common for stars with masses similar to our Sun, but it was unexpected to occur for low mass stars, since their internal structure is different. If the magnetic fields weaken in stars of all masses, this has implications on how these magnetic fields are generated.
Publication: Wright & Drake 2016