Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Les incompatibilites entre la theorie standard de l'extinction
  interstellaire et l'observation   The standard interpretation of the extinction curve does not agree with some
observations. The light we receive from a reddened star must be contaminated by
starlight scattered at very small angular distances from the star. The true
extinction curve is a straight line from the near infrared to the far-UV. If
so, all interstellar dust models must be questionned. A second conclusion is
that the average properties of interstellar grains may be much more uniform
than previously thought.
  --
  L'interpretation standard de la courbe d'extinction de la lumiere par la
matiere interstellaire n'est pas en accord avec certaines observations. Cela
s'explique seulement si la lumiere des etoiles rougies est contaminee par de la
lumiere diffusee a tres faible angle de diffusion. La courbe d'extinction
exacte est alors une ligne droite du proche infrarouge jusqu'a l'UV lointain.
Cela remet en question tous les modeles de poussiere utilises a l'heure
actuelle. Il n'y a egalement pas lieu de supposer de variation des proprietes
moyennes des grains d'une region de l'espace a l'autre.

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The categories of this paper are: cs
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex