Wuppertal 2015 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 7: Sonne und Heliosphäre
EP 7.1: Vortrag
Donnerstag, 12. März 2015, 08:30–08:45, G.10.02 (HS 9)
Variations of 14C around AD 775 and AD 1795 – due to solar activity — •Ralph Neuhäuser and Dagmar L. Neuhäuser — AIU, U Jena, Schillergäßchen 2, 07745 Jena, Germany
The strong 14C increase in data with 1-yr time resolution in the AD 770s (e.g. Miyake et al. 2012) is still a matter of debate. In the last three millenia, there were two more strong rapid rises in 14C – around BC 671 and AD 1795. All three 14C variations are embedded in similar evolution of solar activity, as we can show with various solar activity proxies; secular evolution of solar wind plays an important role. The rises of 14C – within a few years each – can be explained by a sudden strong decrease in solar modulation potential leading to increased radioisotope production.
For the AD 770s, we critically review all known oriental and occidental aurora reports from AD 731 to 825 and find 39 likely true aurorae. There were two aurorae in the early 770s observed near Amida (now Diyarbakir in Turkey near the Turkish-Syrian border). which were not only red, but also green-yellow – being at a relatively low geo-magnetic latitude, they indicate a relatively strong solar storm. However, it cannot be argued that those aurorae (geo-magnetic latitude 43 to 50∘) could be connected to solar super-flares causing the 14C: There are several reports about low- to mid-latitude aurorae at 32 to 44∘ in the 760s and 790s in China and Iraq – always without 14C peaks.