The survival of fossil magnetic fields during pre-main sequence evolution
The survival of fossil magnetic fields during pre-main sequence evolution
复制标题
前主序演化过程中化石磁场的生存
DOI：
10.1051/0004-6361:20030431
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发表时间：
2003
影响因子：
6.5
通讯作者：
D. Moss
中科院分区：
文献类型：
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作者：
D. Moss
在近主序化学特殊（CP）恒星表面发现的强大规模磁场的起源仍然是一个有争议的问题。化石理论将磁场解释为恒星演化早期存在的磁场的残余，它可以更好地解释观测到的CP星磁性。然而，在前主层序演化过程中，是否存在显著的大尺度磁通量，这一问题一直存在争议，但研究很少。在这里，我们试图对存在大尺度对流的通量存续作一些初步的、半定量的估计。我们还提出了一个简单的模型，试图量化从林氏轨道顶部到主层序能够存活的通量的比例。一个广泛的结论是，对于紊流密度等参数的合理值，通量更容易存在于几个太阳质量的恒星中，而不是大约一个太阳质量的恒星中，尽管对比并不像观测所暗示的那样强烈。在模拟主序前恒星演化过程中，不确定性的影响引起了人们的注意。
The origin of the strong large-scale magnetic fields found at the surfaces of the near-main sequence chemically peculiar (CP) stars is still a matter of controversy. The fossil theory, in which the fields are explained as remnants of fields present during earlier stages of stellar evolution, arguably is better able to explain the observed CP star magnetism. However the question of whether significant large-scale magnetic flux can survive through the pre-main sequence evolution has been much disputed, but little explored. Here we attempt to make some preliminary, semi-quantitative estimates related to flux survival in the presence of large-scale convection. We also present a simple model that attempts to quantify the fraction of flux that can survive from the top of the Hayashi track to the main sequence. A broad conclusion is that for plausible values of parameters such as turbulent diusivity, flux can more readily survive in stars of several, rather than about one, solar masses, although the contrast is not as strong as appears to be implied by observations. Attention is drawn to the eects of uncertainties in modelling pre-main sequence stellar evolution.