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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 orcid ; 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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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Nature Communications
volume
6
article number
8611
publisher
Nature Publishing Group
external identifiers
  • pmid:26497389
  • wos:000364934200013
  • scopus:84945301345
  • pmid:26497389
ISSN
2041-1723
DOI
10.1038/ncomms9611
project
Beryllium-10 in highly-resolved natural archives: Solar variability, global synchronization and implications for paleoclimate
language
English
LU publication?
yes
id
4878c665-dc92-4aa9-9c45-8f010622a469 (old id 8148486)
date added to LUP
2016-04-01 13:11:20
date last changed
2022-04-21 20:13:09
@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.}},
  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}},
  doi          = {{10.1038/ncomms9611}},
  volume       = {{6}},
  year         = {{2015}},
}