@article {2015ApJ...799..169S,
	title = {{Orbital and Physical Properties of the {$\sigma$} Ori Aa, Ab, B Triple System}},
	journal = {The Astrophysical Journal},
	volume = {799},
	year = {2015},
	month = {feb},
	pages = {169},
	abstract = {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 data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filh{\'e}s 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 {\plusmn} 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.},
	keywords = {binaries: spectroscopic, open clusters and associations: individual: sigma Orionis, stars: early-type, stars: individual: sigma Ori, stars: massive},
	doi = {10.1088/0004-637X/799/2/169},
	url = {http://adsabs.harvard.edu/abs/2015ApJ...799..169S},
	author = {Sim{\'o}n-D{\'\i}az, S. and Caballero, J.~A. and Lorenzo, J. and Ma{\'\i}z Apell{\'a}niz, J. and Schneider, F.~R.~N. and Negueruela, I. and Barb{\'a}, R.~H. and Dorda, R. and Marco, A. and Montes, D. and Pellerin, A. and J. Sanchez-Bermudez and S{\'o}dor, {\'A}. and Sota, A.}
}
@book {181,
	title = {{The Spanish Square Kilometre Array White Book}},
	series = {ArXiv e-prints},
	year = {2015},
	keywords = {Astrophysics - Instrumentation and Methods for Astrophysics},
	url = {http://adsabs.harvard.edu/abs/2015arXiv150603474A},
	author = {Acosta-Pulido, J.~A. and Agudo, I. and Alberdi, A. and Alcolea, J. and Alfaro, E.~J. and Alonso-Herrero, A. and Anglada, G. and Arnalte-Mur, P. and Ascasibar, Y. and Ascaso, B. and Azulay, R. and Bachiller, R. and Baez-Rubio, A. and Battaner, E. and Blasco, J. and Brook, C.~B. and Bujarrabal, V. and Busquet, G. and Caballero-Garcia, M.~D. and Carrasco-Gonzalez, C. and Casares, J. and Castro-Tirado, A.~J. and Colina, L. and Colomer, F. and de Gregorio-Monsalvo, I. and del Olmo, A. and Desmurs, J.-F. and Diego, J.~M. and Dominguez-Tenreiro, R. and Estalella, R. and Fernandez-Soto, A. and Florido, E. and Font, J. and Font, J.~A. and Fuente, A. and Garc{\'\i}a-Benito, R. and Garcia-Burillo, S. and Garc{\'\i}a-Lorenzo, B. and Gil de Paz, A. and Girart, J.~M. and Goicoechea, J.~R. and G{\'o}mez, J.~F. and Gonzalez-Garcia, M. and Gonz{\'a}lez-Mart{\'\i}n, O. and Gonzalez-Serrano, J.~I. and Gorgas, J. and Gorosabel, J. and Guijarro, A. and Guirado, J.~C. and Hern{\'a}ndez-Garc{\'\i}a, L. and Hernandez-Monteagudo, C. and Herranz, D. and R. Herrero-Illana and Hu, Y.-D. and Huelamo, N. and Huertas-Company, M. and Iglesias-Paramo, J. and Jeong, S. and Jimenez-Serra, I. and Knapen, J.~H. and Lineros, R.~A. and Lisenfeld, U. and Marcaide, J.~M. and Marquez, I. and Marti, J. and Marti, J.~M. and Mart{\'\i}-Vidal, I. and Martinez-Gonzalez, E. and Martin-Pintado, J. and Masegosa, J. and Mayen-Gijon, J.~M. and Mezcua, M. and Migliari, S. and Mimica, P. and Mold{\'o}n, J. and Morata, O. and Negueruela, I. and Oates, S.~R. and Osorio, M. and Palau, A. and Paredes, J.~M. and Perea, J. and P{\'e}rez-Gonz{\'a}lez, P.~G. and Perez-Montero, E. and M. A. P{\'e}rez-Torres and Perucho, M. and Planelles, S. and Pons, J.~A. and Prieto, A. and Quilis, V. and Ramirez-Moreta, P. and Ramos Almeida, C. and Rea, N. and Rib{\'o}, M. and Rioja, M.~J. and Rodriguez Espinosa, J.~M. and Ros, E. and Rubi{\~n}o-Martin, J.~A. and Ruiz-Granados, B. and Sabater, J. and Sanchez, S. and Sanchez-Contreras, C. and Sanchez-Monge, A. and Sanchez-Ramirez, R. and Sintes, A.~M. and Solanes, J.~M. and Sopuerta, C.~F. and Tafalla, M. and Tello, J.~C. and Tercero, B. and Toribio, M.~C. and Torrelles, J.~M. and Torres, M.~A.~P. and Usero, A. and Verdes-Montenegro, L. and Vidal-Garcia, A. and Vielva, P. and Vilchez, J. and Zhang, B.-B.}
}
