Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the age and formation mechanism of the core of the Quadrantid
  meteoroid stream   The Quadrantid meteor shower is among the strongest annual meteor showers,
and has drawn the attention of scientists for several decades. The stream is
unusual, among others, for several reasons: its very short duration around
maximum activity (~12 - 14 hours) as detected by visual, photographic and radar
observations, its recent onset (around 1835 AD) and because it had been the
only major stream without an obvious parent body until 2003. Ever since, there
have been debates as to the age of the stream and the nature of its proposed
parent body, asteroid 2003 EH1.
  In this work, we present results on the most probable age and formation
mechanism of the narrow portion of the Quadrantid meteoroid stream. For the
first time we use data on eight high precision photographic Quadrantids,
equivalent to gram - kilogram size, to constrain the most likely age of the
core of the stream. Out of eight high-precision photographic Quadrantids, five
pertain directly to the narrow portion of the stream. In addition, we also use
data on five high-precision radar Quadrantids, observed within the peak of the
shower.
  We performed backwards numerical integrations of the equations of motion of a
large number of 'clones' of both, the eight high-precision photographic and
five radar Quadrantid meteors, along with the proposed parent body, 2003 EH1.
According to our results, from the backward integrations, the most likely age
of the narrow structure of the Quadrantids is between 200 - 300 years. These
presumed ejection epochs, corresponding to 1700 - 1800 AD, are then used for
forward integrations of large numbers of hypothetical meteoroids, ejected from
the parent 2003 EH$_1$, until the present epoch. The aim is to constrain
whether the core of the Quadrantid meteoroid stream is consistent with a
previously proposed relatively young age (~ 200 years).}

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The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex