论文标题
早期型恒星中磁场的双峰分布的起源
The Origin of the Bimodal Distribution of Magnetic Fields in Early-type Stars
论文作者
论文摘要
在早期型恒星中，可以在恒星形成过程中产生化石磁场，也可以是出色合并事件的结果。认为表面磁场被（子）表面对流层擦除，通常会留下弱无序场。但是，如果化石场足够强大，则可以防止（子）表面对流的发作，因此可以保留到主序列上。我们计算发生这种情况的临界场强度，并发现它与强磁性AP/BP恒星中观察到的磁场的下限幅度（$ \ $ \ $ 300 g）很好。预计在主序列演化期间，临界场强度将略有增加，这也可以解释磁星比例观察到的下降。这支持了以下结论：早期型恒星中观察到的磁场的双峰分布反映了两个不同的田间起源故事：强烈的磁场是从恒星形成或合并事件继承的化石场，而弱场是正在进行的发电机作用的产物。
In early-type stars a fossil magnetic field may be generated during the star formation process or be the result of a stellar merger event. Surface magnetic fields are thought to be erased by (sub)surface convection layers, which typically leave behind weak disordered fields. However, if the fossil field is strong enough it can prevent the onset of (sub)surface convection and so be preserved onto the main sequence. We calculate the critical field strength at which this occurs, and find that it corresponds well with the lower limit amplitude of observed fields in strongly magnetised Ap/Bp stars ($\approx$ 300 G). The critical field strength is predicted to increase slightly during the main sequence evolution, which could also explain the observed decline in the fraction of magnetic stars. This supports the conclusion that the bimodal distribution of observed magnetic fields in early-type stars reflects two different field origin stories: strongly magnetic fields are fossils fields inherited from star formation or a merger event, and weak fields are the product of on-going dynamo action.
