On the cause of luminosity−colour variation in the active binary system DH Leonis
The long term photometric activity of DH Leonis has been compared with the predictions of Applegate's theory that magnetic cycles cause luminosity variation due entirely to temperature variations. Observations show that DH Leo is bluer when it is brighter, but it is found that the slope Δ(B−V)/ΔV is not different from the main sequence slope, which indicates that radius change can not be ruled out
The main objective of this article is to study dynamic of the ::: three-dimensional Boussinesq equations with the periodic boundary ::: condition.We prove that when the Rayleigh number $R$ crosses the ::: first critical Rayleigh number $R_c$, the Rayleigh-Benard problem ::: bifurcates from the basic state to an global attractor $\Sigma$, which is homeomorphic to $S^3$.