Examinando por Autor "Arias, J. I."

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Acceso Abierto
A new spectroscopic analysis of the massive O + O type binary HD 54662 AB
(Oxford Academics: Blackwell Publishing, 2020-04-30) Barbá, R. H.; Sabín Sanjulián, C.; Arias, J. I.; Gamen, R. C.; Morrell, N. I.; Ferrero, G.; Maíz Apellániz, J.; Putkuri, C.; Simón Díaz, S.; Boyajian, T. S.; Fullerton, A. W.; McSwain, M. V.; Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); National Aeronautics & Space Administration (NASA); National Science Foundation (NSF); Dirección de Investigación y Desarrollo (DIDULS) de la Universidad de La Serena; Maíz Apellániz, J. [0000-0003-0825-3443]; Simón Díaz, S. [0000-0003-1168-3524]; Boyajian, T. S. [0000-0001-9879-9313]; Barbá, R. H. [0000-0003-1086-1579]; Arias, J. I. [0000-0001-7500-7352]; Gamen, R. C. [0000-0002-5227-9627]; Morrell, N. I. [0000-0003-2535-3091]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
HD 54662 AB is one of the three O + OB binaries known so far with orbital period longer than 1000 d, offering the opportunity to test scenarios of massive star formation and models of single stellar evolution. Here, we present a detailed study of this system based on new high-resolution spectra and data. A disentangling method is used to recover the individual spectra of the primary and secondary components, which are classified as O6.5 V(n)z and O7.5 Vz, respectively. Combining radial velocity measurements and astrometric data, a new absolute orbit with a period of 2113 +/- 9 d and an eccentricity of 0.062 +/- 0.008 is determined, confirming previous findings. However, absolute masses of 23.8 +/- 1.1 M-circle dot for the primary and 20.3 +/- 1.1 M-circle dot for the secondary are obtained, differing from previous determinations but in reasonable agreement with the spectral types of the stars. Primary and secondary components show remarkably different projected rotational velocities (160 and less than or similar to 40 km s(-1), respectively), which is probably related to the formation process of the binary. Contrary to previously interpretations, the star with broader spectral features is the most massive object in the system. Stellar and wind parameters of both stars are derived through quantitative spectroscopic analysis of the disentangled spectra using FASTWIND models, and they are consistent with the current calibrations for O-type stars. Evolutionary masses and ages are also computed with the BONNSAI tool. Ages below 2.5 Ma are obtained, in agreement with the youth expected from their Vz nature.
Acceso Abierto
MONOS: Multiplicity Of Northern O-type Spectroscopic systems I. Project description and spectral classifications and visual multiplicity of previously known objects
(EDP Sciences, 2019-06-05) Maíz Apellániz, J.; Trigueros Páez, E.; Negueruela, I.; Barbá, R. H.; Simón Díaz, S.; Lorenzo, J.; Sota, A.; Gamen, R. C.; Fariña, C.; Salas, J.; Caballero, J. A.; Morrell, N. I.; Pellerín, A.; Alfaro, E. J.; Herrero, A.; Arias, J. I.; Marco, A.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Cabildo de Gran Canaria; 0000-0003-0825-3443; 0000-0001-6770-1977; 0000-0003-1952-3680; 0000-0001-5358-0932; 0000-0002-9404-6952; 0000-0002-5227-9627; 0000-0002-7349-1387; 0000-0003-1887-1966; 0000-0001-8768-2179; 0000-0002-9594-1879; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFÍSICA DE CANARIAS (IAC), SEV-2015-0548; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Multiplicity in massive stars is key to understanding the chemical and dynamical evolution of galaxies. Among massive stars, those of O type play a crucial role due to their high masses and short lifetimes. Aims. MONOS (Multiplicity Of Northern O-type Spectroscopic systems) is a project designed to collect information and study O-type spectroscopic binaries with δ > −20°. In this first paper we describe the sample and provide spectral classifications and additional information for objects with previous spectroscopic and/or eclipsing binary orbits. In future papers we will test the validity of previous solutions and calculate new spectroscopic orbits. Methods. The spectra in this paper have two sources: the Galactic O-Star Spectroscopic Survey (GOSSS), a project that obtains blue-violet R ∼ 2500 spectroscopy of thousands of massive stars, and LiLiMaRlin, a library of libraries of high-resolution spectroscopy of massive stars obtained from four different surveys (CAFÉ-BEANS, OWN, IACOB, and NoMaDS) and additional data from our own observing programs and public archives. We have also used lucky images obtained with AstraLux. Results. We present homogeneous spectral classifications for 92 O-type spectroscopic multiple systems and ten optical companions, many of them original. We discuss the visual multiplicity of each system with the support of AstraLux images and additional sources. For eleven O-type objects and for six B-type objects we present their first GOSSS spectral classifications. For two known eclipsing binaries we detect double absorption lines (SB2) or a single moving line (SB1) for the first time, to which we add a third system reported by us recently. For two previous SB1 systems we detect their SB2 nature for the first time and give their first separate spectral classifications, something we have also done for a third object just recently identified as a SB2. We also detect nine new astrometric companions and provide updated information on several others. We emphasize the results for two stars: for σ Ori AaAbB we provide spectral classifications for the three components with a single observation for the first time thanks to a lucky spectroscopy observation obtained close to the Aa,Ab periastron and for θ1 Ori CaCb we add it to the class of Galactic Of?p stars, raising the number of its members to six. Our sample of O-type spectroscopic binaries contains more triple- or higher-order systems than double systems.
Acceso Abierto
The IACOB project VI. On the elusive detection of massive O-type stars close to the ZAMS
(EDP Sciences, 2020-06-30) Holgado, G.; Simón Díaz, S.; Haemmerlé, L.; Lennon, D. J.; Barbá, R. H.; Cerviño, M.; Castro, N.; Herrero, A.; Meynet, G.; Arias, J. I.; Agencia Estatal de Investigación (AEI); Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI); Swiss National Science Foundation (SNSF); European Research Council (ERC); Holgado, G. [0000-0002-9296-8259]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The apparent lack of massive O-type stars near the zero-age main sequence, or ZAMS (at ages <2 Myr), is a topic that has been widely discussed in the past 40 yr. Different explanations for the elusive detection of these young massive stars have been proposed from the observational and theoretical side, but no firm conclusions have been reached yet. Aims. We reassess this empirical result here, benefiting from the high-quality spectroscopic observations of (more than 400) Galactic O-type stars gathered by the IACOB and OWN surveys. Methods. We used effective temperatures and surface gravities resulting from a homogeneous semi-automatized IACOB-GBAT/FASTWIND spectroscopic analysis to locate our sample of stars in the Kiel and spectroscopic Hertzsprung-Russell (sHR) diagrams. We evaluated the completeness of our magnitude-limited sample of stars as well as potential observational biases affecting the compiled sample using information from the Galactic O star catalog. We discuss limitations and possible systematics of our analysis method, and compare our results with other recent studies using smaller samples of Galactic O-type stars. We mainly base our discussion on the distribution of stars in the sHR diagram in order to avoid the use of still uncertain distances to most of the stars in our sample. However, we also performed a more detailed study of the young cluster Trumpler-14 as an illustrative example of how Gaia cluster distances can help to construct the associated classical HR diagram. Results. We find that the apparent lack of massive O-type stars near the ZAMS with initial evolutionary masses in the range between ≈30 and 70 M⊙ still persist even when spectroscopic results from a large non-biased sample of stars are used. We do not find any correlation between the dearth of stars close to the ZAMS and obvious observational biases, limitations of our analysis method, and/or the use of one example spectroscopic HR diagram instead of the classical HR diagram. Finally, by investigating the effect of the efficiency of mass accretion during the formation process of massive stars, we conclude that an adjustment of the mass accretion rate towards lower values than canonically assumed might reconcile the hotter boundary of the empirical distribution of optically detected O-type stars in the spectroscopic HR diagram and the theoretical birthline for stars with masses above ≈30 M⊙. Last, we also discuss how the presence of a small sample of O2-O3.5 stars found much closer to the ZAMS than the main distribution of Galactic O-type star might be explained in the context of this scenario when the effect of nonstandard star evolution (e.g. binary interaction, mergers, and/or homogeneous evolution) is taken into account.