Bibcode
Simón-Díaz, S.; Caballero, J. A.; Lorenzo, J.; Maíz Apellániz, J.; Schneider, F. R. N.; Negueruela, I.; Barbá, R. H.; Dorda, R.; Marco, A.; Montes, D.; Pellerin, A.; Sanchez-Bermudez, J.; Sódor, Á.; Sota, A.
Bibliographical reference
The Astrophysical Journal, Volume 799, Issue 2, article id. 169, 12 pp. (2015).
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2
2015
Journal
Citations
44
Refereed citations
40
Description
We provide a complete characterization of the astrophysical properties
of the σ Ori Aa, Ab, B hierarchical triple system and an improved
set of orbital parameters for the highly eccentric σ Ori Aa, Ab
spectroscopic binary. We compiled a spectroscopic data set comprising 90
high-resolution spectra covering a total time span of 1963 days. We
applied the Lehman-Filhés method for a detailed orbital analysis
of the radial velocity curves and performed a combined quantitative
spectroscopic analysis of the σ 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 σ
Ori Aa, Ab pair. We provided indirect arguments indicating that σ
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 σ 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 σ
Orionis cluster, at 3 ± 1 Ma. The outcome of this study will be
of key importance for a precise determination of the distance to the
σ Orionis cluster, the interpretation of the strong X-ray emission
detected for σ Ori Aa, Ab, B, and the investigation of the
formation and evolution of multiple massive stellar systems and
substellar objects.
Related projects
The IACOB project: A new Era in the Study of Galactic OB Stars
IACOB is an ambitious long-term project whose main scientific goal is to provide an unprecedented empirical overview of the main physical properties of Galactic massive O- and B-type stars which can be used as definitive anchor point for our theories of stellar atmospheres, winds, interiors and evolution of massive stars
Sergio
Simón Díaz