The central region of a star, in which hydrogen burning occurs while the star is on the main sequence. After the star has left the main sequence, the core is the site of further nuclear burning of other fuels such as helium and oxygen. About 30% of the mass of a star of 10 solar masses is in its core. In such massive stars the cores are entirely convective, ensuring that the region is well mixed and of uniform composition. Stars of less than 0.4 solar masses are convective in both their cores and their envelopes. Stars of 0.4–1.2 solar masses have radiative cores.
Subjects: Astronomy and Astrophysics.