The roughly horizontal path on the Hertzsprung–Russell diagram followed by a pre-main-sequence star with a mass greater than about 0.4 solar masses. The track takes it on to the main sequence after it has descended the Hayashi track. Stars on Henyey tracks are becoming hotter, and therefore bluer, as they contract. The contraction ends once the core is hot enough for hydrogen burning to begin and the star joins the main sequence. Whereas stars on Hayashi tracks are fully convective, those on Henyey tracks are radiative. It is named after the American astrophysicist Louis George Henyey (1910–70).