The nearby star Proxima Centauri hosts an Earth-sized planet (called Proxima b) in its habitable zone but the star seems nothing like our sun. It's a small, cool, red dwarf star only one-tenth as massive and one-thousandth as luminous as the sun. However, new research shows that it is sunlike in one surprising way: it has a regular cycle of starspots.
Starspots (like sunspots) are dark blotches on a star's surface where the temperature is a little cooler than the surrounding area. They are driven by magnetic fields. A star is made of ionized gases called plasma. Magnetic fields can restrict the plasma's flow and create spots. Changes to a star's magnetic field can affect the number and distribution of starspots.