to produce a steep temperature gradient. This combination of circumstances produces an outer convection zone, the top of which is visible in the Sun as solar granulation. Low mass main sequences of stars, such as red dwarfs below 0.35 solar masses, as well as pre-main sequence stars on the Hayashi track, are convective throughout and do not contain a radiation zone. In main sequence stars similar to the Sun, which have a radiative core and convective envelope, the transition region between the convection zone and the radiation zone is called the tachocline. Red giants In red giant stars, and particularly during the asymptotic giant branch phase, the surface convection zone varies in depth during the phases of shell burning. This causes dredge-up events, short-lived very deep convection zones that transport fusion products to the surface of the star. References Further reading External links Animated explanation of the Convection zone (University of South Wales). Animated explanation of the temperature and density of the Convection zone (University of South Wales). Convection Stellar phenomena