Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transitional YSOs: Candidates from Flat-Spectrum IRAS Sources   We are searching for Young Stellar Objects (YSOs) near the boundary between
protostars and pre-main sequence objects, what we have termed transitional
YSOs. We have identified a sample of 125 objects as candidate transitional YSOs
on the basis of IRAS colors and optical appearance on DSS images. We find that
the majority of our objects are associated with star-forming regions,
confirming our expectation that the bulk of these are YSOs.
  We present optical, near-IR and high-resolution IRAS images of 92 objects
accessible from the northern and 62 from the southern hemisphere. The objects
have been classified on the basis of their morphology and spectral index. Of
the 125 objects, 28 have a variety of characteristics very similar to other
transitional YSOs, while another 22 show some of these characteristics,
suggesting that these transitional YSOs are not as rare as predicted by theory.

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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: nlin