Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Molecular Lines in Bok Globules and Around Herbig Ae/be Stars   This paper is intended as part of a more extensive molecular line survey in
star forming regions along the evolutionary track of a collapsing cloud toward
a young stellar object. We have studied a sample of seven small dark clouds
(Bok globules) and eight Herbig Ae/Be stars in the J=1->0 transition of
HCO$^{+}$, H$^{13}$CO$^{+}$, HCN and H$^{13}$CN. The choice of these molecules
is determined by the simple chemistry and the predicted high abundance of the
reactants leading to their formation. The isotopically substituted species
(isotopomers), H$^{13}$CO$^{+}$ and H$^{13}$CN, were observed in order to
determine, whenever possible, the optical thickness of the main species. The
most abundant isotopomers were found in almost all the sources (detection rate
70-90\%). Those sources which exhibited the strongest signals were also
searched for the $^{13}$C isotopomers. H$^{13}$CO$^{+}$ was found in one dark
cloud and around three Herbig Ae/Be stars, while H$^{13}$CN around only one
star. The column densities for each species and the physical conditions of the
objects were derived whenever the observational data allowed it.

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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
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The categories of this paper are: adap-org
1
The categories of this paper are: cs
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: q-fin
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: nlin