Low Mass Star, Artist Concept
An artist's illustration depicts the interior of a low mass star. Such stars have different interior structures than our Sun, so they are not expected to show magnetic activity cycles. However, in 2016 astronomers announced that the nearby star Proxima Centauri hosts an Earth-sized planet (called Proxima b) in its habitable zone. At first glance, Proxima Centauri 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. Our Sun experiences an 11-year activity cycle. At the solar minimum, the Sun is nearly spot-free. At solar maximum, typically more than 100 sunspots cover less than one percent of the Sun’s surface on average. The new study finds that Proxima Centauri undergoes a similar cycle lasting seven years from peak to peak. However, its cycle is much more dramatic. At least a full one-fifth of the star’s surface is covered in spots at once. Also, some of those spots are much bigger relative to the star’s size than the spots on our Sun.
Size: 3750px × 3750px
Location:
Photo credit: © Science History Images / Alamy / Afripics
License: Licensed
Model Released: No
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