标题： T Tauri恒星的磁制动 显示英文标题

标题： Magnetic braking of T Tauri stars

摘要： 我们构建了T Tauri恒星旋转速率的模型，其自转受到恒星与周围吸积盘之间的磁链接调控。 我们的模型使用一个时间依赖的盘代码来跟踪吸积过程，并包括前主序星演化的影响。 我们发现初始盘质量控制着星-盘系统的演化。 对于足够质量的盘，在经典的T Tauri阶段，恒星磁场$\sim$ 1 kG能够将自转速率调节到观测值。 然后磁场会促使盘被驱散，恒星在角动量保持不变的情况下加速旋转，形成弱线系统。 低质量的盘会在早期被驱散，无法显著制动恒星。 我们将模型扩展到密近双星系统，并发现次星从盘中移除角动量显著延长了内盘的寿命。 因此，这类系统应该是相对较慢的旋转体。 我们还讨论了该模型对T Tauri恒星的光谱能量分布和变异性的影响。 显示英文摘要

摘要： We construct models for the rotation rates of T Tauri stars whose spin is regulated by magnetic linkage between the star and a surrounding accretion disc. Our models utilise a time-dependent disc code to follow the accretion process and include the effects of pre-main-sequence stellar evolution. We find that the initial disc mass controls the evolution of the star-disc system. For sufficiently massive discs, a stellar field of $\sim$ 1 kG is able to regulate the spin rate to the observed values during the classical T Tauri phase. The field then acts to expel the disc and the star spins up at constant angular momentum as a weak-line system. Lower mass discs are ejected at an early epoch and fail to brake the star significantly. We extend the model to close binary systems, and find that the removal of angular momentum from the disc by the secondary significantly prolongs the inner disc lifetime. Such systems should therefore be relatively slow rotators. We also discuss the implications of our model for the spectral energy distributions and variability of T Tauri stars.