Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Massive Stars: Their Birth Sites and Distribution   The stellar IMF has been found to be an invariant Salpeter power-law
(alpha=2.35) above about 1 Msun, but at the same time a massive star typically
has more than one companion. This constrains the possible formation scenarios
of massive stars, but also implies that the true, binary-star corrected stellar
IMF could be significantly steeper than Salpeter, alpha>2.7. A significant
fraction of all OB stars are found relatively far from potential birth sites
which is most probably a result of dynamical ejections from cores of
binary-rich star clusters. Such cores form rapidly due to dynamical mass
segregation, or they are primordial. Probably all OB stars thus form in stellar
clusters together with low-mass stars, and they have a rather devastating
effect on the embedded cluster by rapidly driving out the remaining gas leaving
expanding OB associations and bound star clusters. The distributed population
of OB stars has a measured IMF with alpha about 4, which however, does not
necessarily constitute a different physical mode for isolated star formation. A
steep field-star IMF is obtained naturally because stars form in clusters which
are distributed according to a power-law cluster mass function.

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The categories of this paper are: hep-th
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The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: stat
12
The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
3
The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn