恢复活力：一个重要但被忽视的质量和angular momentum来源
Rejuvenating infall: a crucial yet overlooked source of mass and angular momentum
摘要：
MHD模型和吸积流的观测证实，原恒星在初始坍缩阶段之后可以经历晚期吸积事件。为了提供更好的约束条件，我们在（4 pc）^3分子云的MHD模拟中研究了恒星质量的演化。示踪粒子使我们能够准确地跟踪所有原恒星的吸积物质的轨迹，从而限制恒星的吸积库。吸积过程的多样性意味着太阳质量范围内的恒星可以有截然不同的吸积历史。有些恒星在初始坍缩阶段会吸积大部分的质量，而其他恒星则会在后期坍缩阶段获得超过50%的最终质量。经历大量下沉的恒星的角动量预算，所谓的晚期吸积物，明显高于没有或只有很少晚期吸积的恒星。由于后期坠落的概率随着最终恒星质量的增加而增加，因此质量更高的恒星的比角动量预算平均更高。假设的离心半径计算的吸积粒子在形成时的数量级高于观察到的磁盘大小，这强调了在磁盘形成过程中的角动量传输的重要性。然而，我们发现一个相关性，即离心半径是最高的恒星与实质性的下降，这表明，非常大的磁盘是最近的下降事件的结果。也有迹象表明，离心半径的增加与最终恒星质量，这是在一个观察到的边缘相关的磁盘大小和恒星质量增加的微妙趋势。最后，我们表明，后期吸积物成为嵌入再次在下降。因此，晚期的吸积物（显然）会重新焕发活力，根据它们的热测量温度，尽管有100万年的历史，但仍被归类为0类天体。
英文摘要：
MHD models and the observation of accretion streamers confirmed that protostars can undergo late accretion events after the initial collapse phase. To provide better constraints, we study the evolution of stellar masses in MHD simulations of a (4 pc)^3 molecular cloud. Tracer particles allow us to accurately follow the trajectory of accreting material for all protostars and thereby constrain the accretion reservoir of the stars. The diversity of the accretion process implies that stars in the solar mass regime can have vastly different accretion histories. Some stars accrete most of their mass during the initial collapse phase, while others gain >50 % of their final mass from late infall. The angular momentum budget of stars that experience substantial infall, so-called late accretors, is significantly higher than for stars without or with only little late accretion. As the probability of late infall increases with increasing final stellar mass, the specific angular momentum budget of higher mass stars is on average higher. The hypothetical centrifugal radius computed from the accreting particles at the time of formation is orders of magnitude higher than observed disk sizes, which emphasizes the importance of angular momentum transport during disk formation. Nevertheless, we find a correlation that the centrifugal radius is highest for stars with substantial infall, which suggests that very large disks are the result of recent infall events. There are also indications for a subtle trend of increasing centrifugal radius with increasing final stellar mass, which is in agreement with an observed marginal correlation of disk size and stellar mass. Finally, we show that late accretors become embedded again during infall. As a consequence, late accretors are (apparently) rejuvenated and would be classified as Class 0 objects according to their bolometric temperature despite being 1 Myr old.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
