The widths of the lines show occasional as well as longer term changes of a few percent but no evidence for giant convection ... cells appear on the stellar disk at all times. Freytag, B. 2001, in ASP ...

"It seems that convection changes as a star gets ... than the timeline followed by similar convective cells abundant on our sun's surface. "We don't yet know what is the reason for the difference ...

Convection, a well-known process in geology, occurs when heated material rises toward a planet's surface and cooler materials sink, creating a constant conveyor belt of sorts. On Earth ...