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Abstract: Ice cores are known to be rich in information regarding past climates, andthe possibility that they record astronomical phenomena has also beendiscussed. Rood et al. were the first to suggest, in 1979, that nitrate ionNO3- concentration spikes observed in the depth profile of a South Pole icecore might correlate with the known historical supernovae SNe, Tycho AD1572, Kepler AD 1604, and SN 1181 AD 1181. Their findings, however, werenot supported by subsequent examinations by different groups using differentice cores, and the results have remained controversial and confusing. Here wepresent a precision analysis of an ice core drilled in 2001 at Dome Fujistation in Antarctica. It revealed highly significant three NO3- spikes datingfrom the 10th to the 11th century. Two of them are coincident with SN 1006 AD1006 and the Crab Nebula SN AD 1054, within the uncertainty of our absolutedating based on known volcanic signals. Moreover, by applying time-seriesanalyses to the measured NO3- concentration variations, we discovered veryclear evidence of an 11-year periodicity that can be explained by solarmodulation. This is one of the first times that a distinct 11-year solar cyclehas been observed for a period before the landmark studies of sunspots byGalileo Galilei with his telescope. These findings have significantconsequences for the dating of ice cores and galactic SN and solar activityhistories.



Autor: Yuko Motizuki, Kazuya Takahashi, Kazuo Makishima, Aya Bamba, Yoichi Nakai, Yasushige Yano, Makoto Igarashi, Hideaki Motoyama, Kok

Fuente: https://arxiv.org/







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