Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The 2011 October Draconids outburst. I. Orbital elements, meteoroid
  fluxes and 21P/Giacobini-Zinner delivered mass to Earth   On October 8th, 2011 the Earth crossed the dust trails left by comet
21P/Giacobini-Zinner during its XIX and XX century perihelion approaches with
the comet being close to perihelion. The geometric circumstances of that
encounter were thus favorable to produce a meteor storm, but the trails were
much older than in the 1933 and 1946 historical encounters. As a consequence
the 2011 October Draconid display exhibited several activity peaks with
Zenithal Hourly Rates of about 400 meteors per hour. In fact, if the display
had been not forecasted, it could have passed almost unnoticed as was strongly
attenuated for visual observers due to the Moon. This suggests that most meteor
storms of a similar nature could have passed historically unnoticed under
unfavorable weather and Moon observing conditions. The possibility of obtaining
information on the physical properties of cometary meteoroids penetrating the
atmosphere under low-geocentric velocity encounter circumstances motivated us
to set up a special observing campaign. Added to the Spanish Fireball Network
wide-field all-sky and CCD video monitoring, other high-sensitivity 1/2" black
and white CCD video cameras were attached to modified medium-field lenses for
obtaining high resolution orbital information. The trajectory, radiant, and
orbital data of 16 October Draconid meteors observed at multiple stations are
presented. The results show that the meteors appeared from a geocentric radiant
located at R.A.=263.0+-0.4 deg. and Dec.=+55.3+-0.3 deg. that is in close
agreement with the radiant predicted for the 1873-1894 and the 1900 dust
trails. The estimated mass of material from 21P/Giacobini-Zinner delivered to
Earth during the six-hours outburst was around 950+-150 kg.

10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat