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Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4.

Mekhaldi, Florian LU ; Muscheler, Raimund LU ; Adolphi, Florian LU ; Aldahan, Ala; Beer, Jürg; McConnell, Joseph R; Possnert, Göran; Sigl, Michael; Svensson, Anders and Synal, Hans-Arno, et al. (2015) In Nature Communications 6.
Abstract
The origin of two large peaks in the atmospheric radiocarbon ((14)C) concentration at AD 774/5 and 993/4 is still debated. There is consensus, however, that these features can only be explained by an increase in the atmospheric (14)C production rate due to an extraterrestrial event. Here we provide evidence that these peaks were most likely produced by extreme solar events, based on several new annually resolved (10)Be measurements from both Arctic and Antarctic ice cores. Using ice core (36)Cl data in pair with (10)Be, we further show that these solar events were characterized by a very hard energy spectrum with high fluxes of solar protons with energy above 100 MeV. These results imply that the larger of the two events (AD 774/5) was at... (More)
The origin of two large peaks in the atmospheric radiocarbon ((14)C) concentration at AD 774/5 and 993/4 is still debated. There is consensus, however, that these features can only be explained by an increase in the atmospheric (14)C production rate due to an extraterrestrial event. Here we provide evidence that these peaks were most likely produced by extreme solar events, based on several new annually resolved (10)Be measurements from both Arctic and Antarctic ice cores. Using ice core (36)Cl data in pair with (10)Be, we further show that these solar events were characterized by a very hard energy spectrum with high fluxes of solar protons with energy above 100 MeV. These results imply that the larger of the two events (AD 774/5) was at least five times stronger than any instrumentally recorded solar event. Our findings highlight the importance of studying the possibility of severe solar energetic particle events. (Less)
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Nature Communications
volume
6
publisher
Nature Publishing Group
external identifiers
  • pmid:26497389
  • wos:000364934200013
  • scopus:84945301345
ISSN
2041-1723
DOI
10.1038/ncomms9611
language
English
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yes
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4878c665-dc92-4aa9-9c45-8f010622a469 (old id 8148486)
date added to LUP
2015-11-18 16:30:34
date last changed
2017-11-05 03:54:00
@article{4878c665-dc92-4aa9-9c45-8f010622a469,
  abstract     = {The origin of two large peaks in the atmospheric radiocarbon ((14)C) concentration at AD 774/5 and 993/4 is still debated. There is consensus, however, that these features can only be explained by an increase in the atmospheric (14)C production rate due to an extraterrestrial event. Here we provide evidence that these peaks were most likely produced by extreme solar events, based on several new annually resolved (10)Be measurements from both Arctic and Antarctic ice cores. Using ice core (36)Cl data in pair with (10)Be, we further show that these solar events were characterized by a very hard energy spectrum with high fluxes of solar protons with energy above 100 MeV. These results imply that the larger of the two events (AD 774/5) was at least five times stronger than any instrumentally recorded solar event. Our findings highlight the importance of studying the possibility of severe solar energetic particle events.},
  articleno    = {8611},
  author       = {Mekhaldi, Florian and Muscheler, Raimund and Adolphi, Florian and Aldahan, Ala and Beer, Jürg and McConnell, Joseph R and Possnert, Göran and Sigl, Michael and Svensson, Anders and Synal, Hans-Arno and Welten, Kees C and Woodruff, Thomas E},
  issn         = {2041-1723},
  language     = {eng},
  publisher    = {Nature Publishing Group},
  series       = {Nature Communications},
  title        = {Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4.},
  url          = {http://dx.doi.org/10.1038/ncomms9611},
  volume       = {6},
  year         = {2015},
}