Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Follow-up observations of X-ray emitting hot subdwarf star: the He-rich
  sdO BD +37{\deg} 1977   We report on the results of the first XMM-Newton satellite observation of the
luminous and helium-rich O-type subdwarf BD +37{\deg} 1977 carried out in April
2014. X-ray emission is detected with a flux of about 4*10^(-14) erg/cm2/s
(0.2-1.5 keV), corresponding to a f_X/f_bol ratio about 10^(-7); the source
spectrum is very soft, and is well fit by the sum of two plasma components at
different temperatures. Both characteristics are in agreement with what is
observed in the main-sequence early-type stars, where the observed X-ray
emission is due to turbulence and shocks in the stellar wind. A smaller but
still significant stellar wind has been observed also in BD +37{\deg} 1977;
therefore, we suggest that also in this case the detected X-ray flux has the
same origin.

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The categories of this paper are: math-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: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: funct-an
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The categories of this paper are: acc-phys