Grids of rotating stellar models with masses between 1.0 and 3.0M_⊙

Abstract

We calculated a grid of evolutionary tracks of rotating models with masses between 1.0 and 3.0 M ⊙ and a resolution δM ≤ 0.02 M ⊙ , which can be used to study the effects of rotation on stellar evolutions and on the characteristics of star clusters. The value of ∼2.05 M ⊙ is a critical mass for the effects of rotation on stellar structure and evolution. For stars with M > 2.05 M ⊙ , rotation leads to an increase in the convective core and prolongs the lifetime of main sequence (MS); rotating models evolve slower than non-rotating ones; the effects of rotation on the evolution of these stars are similar to those of convective core overshooting. However for stars with 1.1 < M/M ⊙ < 2.05, rotation results in a decrease in the convective core and shortens the lifetime of MS; rotating models evolve faster than non-rotating ones. When the mass is located in the range of ∼1.7 -2.0 M ⊙ , the mixing caused by rotationally induced instabilities is not efficient; the hydrostatic effects dominate the effect on the evolution of these stars. For the models with masses between about 1.6 and 2.0 M ⊙ , rotating models always exhibit lower effective temperatures than non-rotating ones at the same age during the MS stage. For a given age, the lower the mass, the smaller the change in the effective temperature. Thus rotations could lead to a color spread near the MS turnoff in the color-magnitude diagram for the intermediate-age star clusters.

Solar Models With New Low metal Abundances

“…This reflects that rotation and convection overshoot may be important in the evolution of the Sun. Moreover, rotation plays an important role in the formation of the extended main-sequence turnoff of intermediate-age massive star clusters (Yang et al 2013a(Yang et al , 2013b,and convection overshoot plays an essential role in explaining some of thecharacteristics of solar-like oscillations Figure 6. Distributions of the ratios of small to large separations, r 02 and r 13 , as a function of frequency.…”

“…Rotational and turbulent mixing can reduce the surface helium settling (Proffitt & Michaud 1991;Yang & Bi 2006;Turck-Chièze et al 2010;Yang et al 2013aYang et al , 2013b,but the position of the CZ base of rotating models with low Z is too shallow (Yang & Bi 2007). Montalbán et al (2006) and Castro et al (2007) showed that convective overshoot can bring the depth of the CZ into agreement with the seismic value.…”

“…The effects of rotation on the structure and evolution of stars include thecentrifugal effect and rotational mixing (Pinsonneault et al 1989;Yang & Bi 2006;Turck-Chièze et al 2010;Yang et al 2013aYang et al , 2013b. The mechanisms of rotational mixing, considered in this work, include the hydrodynamical instabilities (Pinsonneault et al 1989) and secular shear instability (Zahn et al 1997).…”

The Effects of Rotation on the Main-Sequence Turnoff of Intermediate-Age Massive Star Clusters

“…(3) The Von Zeipel effect and the mixing of elements can affect the instability of convection by changing the radiative and adiabatic temperature gradients. If the convective core increases, the lifetime of the MS will be prolonged, and vice versa (Maeder 1987;Talon et al 1997;Maeder & Meynet 2000;Yang et al 2013a).…”

“…Moreover, Bastian & de Mink (2009) only calculated the evolution of a star with the mass of 1.5 M ⊙ , assuming that the results for the star can be applied to others. In fact, the effects of rotation on the structure and evolution of stars depend on the mass of stars for a given rotation rate (Maeder & Meynet 2000;Yang et al 2013a). On the contrary, however, in the models of Girardi et al (2011), the effects of the mixing may be more efficient, which results in the fact that their rotating models have a higher effective temperature than non-rotating ones in the late stage of the MS for stars of any mass.…”