The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity
The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity
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DOI：
10.1007/s11207-019-1424-8
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发表时间：
2019-03
期刊：
影响因子：
2.8
通讯作者：
Hisashi Hayakawa;Hisashi Hayakawa;F. Stephenson;Yuta Uchikawa;Yuta Uchikawa;Y. Ebihara;Chris J. Scott;M. N. Wild;J. Wilkinson;David M. Willis;David M. Willis
中科院分区：
文献类型：
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作者：
Hisashi Hayakawa;Hisashi Hayakawa;F. Stephenson;Yuta Uchikawa;Yuta Uchikawa;Y. Ebihara;Chris J. Scott;M. N. Wild;J. Wilkinson;David M. Willis;David M. Willis
774/775中放射性碳的异常浓度引发了对其起源的激烈讨论，其中包括可能超过观测历史上任何事件的极端太阳事件。为了预见到这种极端的太阳事件，历史文献中也对极光记录进行了调查，包括盎格鲁撒克逊编年史（ASC）中日落后的红色天象在内的极光记录也受到了考虑。 Usoskinet al.(Astron. Astrophys.55, L3, 2013: U13) 将这一记录解释为极光，并表明太阳活动在 774/775 左右增强。相反，Neuhäuser 和 Neuhäuser (Astron. Nachr.336, 225, 2015a: N15a;Astron. Nachr.336, 913, 2015b: N15b) 将“日落之后”解释为日落或黄昏期间；他们认为这个迹象是光环显示，并建议太阳活动极小期在 774 年左右。然而，到目前为止，这些记录尚未与已知极端太空天气事件期间目击者极光记录进行比较，尽管它们与 774/775 年潜在极端事件的关系进行了讨论。因此，我们根据ASC的原始记录和文献参考文献重建观测细节，将其与已知极端太空天气事件期间目击者的极光观测进行比较，并考虑当代太阳活动。我们澄清观测确实是“日落之后”，拒绝日晕假说，定义观测时间跨度为775年3月25日至777年12月25日，并注意到N15b中显示的ASC中806年平行的“月晕显示图”并非基于英国的原始观测。我们展示了在已知太空天气事件中的黄昏期间目击者观测极光的例子，并且这个天体迹象与观测证据并不矛盾。因此，我们认为该事件发生在 774/775 年事件发生之后，但与 770 年代中期的其他历史极光记录相比，显示出相对增强的太阳活动，冰芯的 10Be 数据也证实了这一点。
The anomalous concentration of radiocarbon in 774/775 attracted intense discussion on its origin, including the possible extreme solar event(s) exceeding any events in observational history. Anticipating such extreme solar events, auroral records were also surveyed in historical documents and those including the red celestial sign after sunset in the Anglo-Saxon Chronicle (ASC) were subjected to consideration. Usoskinet al.(Astron. Astrophys.55, L3, 2013: U13) interpreted this record as an aurora and suggested enhanced solar activity around 774/775. Conversely, Neuhäuser and Neuhäuser (Astron. Nachr.336, 225, 2015a: N15a;Astron. Nachr.336, 913, 2015b: N15b) interpreted “after sunset” as during sunset or twilight; they considered this sign as a halo display and suggested a solar minimum around 774. However, so far these records have not been discussed in comparison with eyewitness auroral records during the known extreme space weather events, although they were discussed in relationship with potential extreme events in 774/775. Therefore, we reconstruct the observational details based on the original records in the ASC and philological references, compare them with eyewitness auroral observations during known extreme space weather events, and consider contemporary solar activity. We clarify the observation was indeed “after sunset”, reject the solar-halo hypothesis, define the observational time span between 25 March 775 and 25 December 777, and note that the parallel “drawing of lunar halo display” in 806 in the ASC shown in N15b was not based on the original observation in England. We show examples of eyewitness auroral observations during twilight in known space weather events, and this celestial sign does not contradict the observational evidence. Accordingly, we consider this event to have happened after the onset of the event in 774/775, but to have shown relatively enhanced solar activity, with regard to other historical auroral records in the mid-770s, as also confirmed by the10Be data from ice cores.