Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Orbital and physical properties of the $\sigma$ Ori Aa,Ab,B triple
  system   We provide a complete characterization of the astrophysical properties of the
$\sigma$ Ori Aa,Ab,B hierarchical triple system, and an improved set of orbital
parameters for the highly eccentric $\sigma$ Ori Aa,Ab spectroscopic binary.
  We compiled a spectroscopic dataset comprising 90 high-resolution spectra
covering a total time span of 1963 days. We applied the Lehman-Filh\'es method
for a detailed orbital analysis of the radial velocity curves and performed a
combined quantitative spectroscopic analysis of the {$\sigma$ Ori Aa,Ab,B}
system by means of the stellar atmosphere code FASTWIND. We used our own plus
other available information on photometry and distance to the system for
measuring the radii, luminosities, and spectroscopic masses of the three
components. We also inferred evolutionary masses and stellar ages using the
Bayesian code BONNSAI.
  The orbital analysis of the new radial velocity curves led to a very accurate
orbital solution of the $\sigma$ Ori Aa,Ab pair. We provided indirect arguments
indicating that $\sigma$ Ori B is a fast rotating early-B dwarf. The
FASTWIND+BONNSAI analysis showed that the Aa,Ab pair contains the hottest and
most massive components of the triple system while $\sigma$ Ori B is a bit
cooler and less massive. The derived stellar ages of the inner pair are
intriguingly younger than the one widely accepted for the $\sigma$ Orionis
cluster, at 3$\pm$1 Ma.
  The outcome of this study will be of key importance for a precise
determination of the distance to the $\sigma$ Orionis cluster, the
interpretation of the strong X-ray emission detected for $\sigma$ Ori Aa,Ab,B,
and the investigation of the formation and evolution of multiple massive
stellar systems and substellar objects.

25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph