Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The lost sunspot cycle: New support from Be10 measurements   It has been suggested that the deficit in the number of spots on the surface
of the Sun between 1790 and 1830, known as the Dalton minimum, contained an
extra cycle that was not identified in the original sunspot record by Wolf.
Though this cycle would be shorter and weaker than the average solar cycle, it
would shift the magnetic parity of the solar magnetic field of the earlier
cycles. This extra cycle is sometimes referred to as the 'lost solar cycle' or
'cycle 4b'. Here we reanalyse Be10 measurements with annual resolution from the
NGRIP ice core in Greenland in order to investigate if the hypothesis regarding
a lost sunspot cycle is supported by these measurements. Specifically, we make
use of the fact that the Galactic cosmic rays, responsible for forming Be10 in
the Earth's atmosphere, are affected differently by the open solar magnetic
field during even and odd solar cycles. This fact enables us to evaluate if the
numbering of cycles earlier than cycle 5 is correct. For the evaluation, we use
Bayesian analysis, which reveals that the lost sunspot cycle hypothesis is
likely to be correct. We also discuss if this cycle 4b is a real cycle, or a
phase catastrophe, and what implications this has for our understanding of
stellar activity cycles in general.

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The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
9
The categories of this paper are: nlin