Subvenciones relacionadas:
General
Las estrellas masivas son objetos claves para la Astrofísica. Estas estrellas nacen con más de 8 masas solares, lo que las condena a morir como Supernovas. Durante su rápida evolución liberan, a través de fuertes vientos estelares, gran cantidad de material procesado en su núcleo y, en determinadas fases evolutivas, emiten gran cantidad de radiación ionizante. Como consecuencia, las estrellas masivas juegan un papel fundamental en muchos aspectos de la evolución del Cosmos; p. ej., son uno de los motores principales de la evolución química y dinámica de las galaxias y han sido propuestas como agentes clave en la reionización del Universo. A lo largo de su evolución, se asocian con los objetos estelares mas extremos (estrellas O y WR; supergigantes azules y rojas; variables luminosas azules; agujeros negros, estrellas de neutrones y magnetars; estrellas binarias masivas de rayos X y gamma). También son el origen de los GRBs de larga duración y están asociadas con las recientes detecciones de ondas gravitacionales. Desde un punto de vista practico, las estrellas masivas son valiosos indicadores de abundancias y distancias en galaxias externas, incluso mas allá del Grupo Local. Ademas, la interpretación de la luz emitida por regiones HII y galaxias starburst se basa en nuestro conocimiento del efecto que produce la radiación ionizante emitida por las estrellas masivas en el medio interestelar.
Este proyecto esta enfocado a la búsqueda, observación y análisis de estrellas masivas en galaxias cercanas con la finalidad de proporcionar un marco empírico solido que nos permita entender sus propiedades físicas en función de parámetros clave que gobiernan su evolución (tales como masa, rotacion, metalicidad, perdida de masa e interacción binaria). Para ello, el proyecto se basa en observaciones de gran calidad obtenidas con telescopios de los observatorios de Canarias y de la ESO, complementadas con otras observaciones de interés proporcionadas por misiones espaciales como Gaia, HST, IUE y TESS. Como una parte clave de este proyecto, observaciones espectroscópicas de estrellas masivas en distintos estados evolutivos y localizadas en entornos de diferente metalicidad son analizadas haciendo uso de la ultima generación de códigos de atmósfera estelar y herramientas de análisis espectroscópico cuantitativo optimizadas para estrellas masivas con la finalidad de extraer la mayor cantidad de información empírica posible sobre parámetros estelares y abundancias.
Las principales lineas activas en el proyecto son:
- la observación y análisis de grandes muestras de estrellas OB en la Vía Láctea;
- la exploración de la población estelar masiva localizada en regiones oscurecidas de la Vía Láctea;
- la búsqueda, observación y análisis de estrellas masivas extragalácticas, poniendo un especial énfasis en galaxias de baja metalicidad;
- el desarrollo y uso de modelos de atmósfera, modelos atómicos y herramientas numéricas para el análisis de estrellas masivas.
Miembros
Resultados
- Como parte de su tesis, S.R. Berlanas ha publicado una serie de tres articulos en los que se estudian en detalle varios aspectos relacionados con la poblacion estelar masiva de la asociacion Cygnus OB2 utilizando espectroscopia obtenida con INT y datos de paralajes proporcinoados por Gaia DR2.
- G. Holgado ha finalizado su tesis doctoral en la que presenta un estudio espectroscopico detallado de la muestra de estrellas O Galacticas más grande considerada hasta el momento.
- Hemos investigado en detalle la variabilidad espectroscopica y fotometrica de dos supergigantes azules (rho Leo y kappa Cas) a partir de espectroscopia multiepoca HERMES/FIES/SONG y datos fotometricos proporcionados por las misiones Hipparcos y K2. Nuestros analisis apuntan hacia la confirmacion de la existencia de "internal gravity waves" en este tipo de estrellas.
- Hemos encontrado dos nuevas acumulaciones de estrellas masivas en la Via Lactea con un alineamiento casual (MASGOMAS-6A+B). Localizadas a una longitud Galactica de 38 grados, la primera acumulacion (a 3.9 kpc) continene 2 estrellas WR y varias enanas O, mientras que la segunda (a 9.6 kpc) contine una LBV y una poblacion evolucionada de supergigantes azules.
- Hemos contribuido a presentar un censo actualizado de la población estelar masiva del cúmulo del Quintuplete, uno de los cúmulos jovenes más masivos en la Galaxia.
Actividad científica
Publicaciones relacionadas
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The chemical composition of the Orion star forming region. III. C, N, Ne, Mg, and Fe abundances in B-type stars revisitedContext. Early B-type stars are invaluable indicators of elemental abundances of their birth environments. In contrast to the surrounding neutral interstellar matter (ISM) and H ii regions, their chemical composition is unaffected by depletion onto dust grains and the derivation of different abundances from recombination and collisional lines. InNieva, M.-F. et al.
Fecha de publicación:
82011 -
The chemical composition of the Orion star forming region. I. Homogeneity of O and Si abundances in B-type starsContext. Recent accurate abundance analyses of B-type main sequence stars in the solar vicinity has shown that abundances derived from these stellar objects are more homogeneous and metal-rich than previously thought. Aims: We investigate whether the inhomogeneity of abundances previously found in B-type stars in the Ori OB1 association is realSimón-Díaz, S.
Fecha de publicación:
22010 -
NGC 1624-2: a slowly rotating, X-ray luminous Of?cp star with an extraordinarily strong magnetic fieldThis paper presents a first observational investigation of the faint Of?p star NGC 1624-2, yielding important new constraints on its spectral and physical characteristics, rotation, magnetic field strength, X-ray emission and magnetospheric properties. Modelling the spectrum and spectral energy distribution, we conclude that NGC 1624-2 is a mainWade, G. A. et al.
Fecha de publicación:
92012 -
Erratum: The VLT-FLAMES survey of massive stars: atmospheric parameters and rotational velocity distributions for B-type stars in the Magellanic CloudsWe correct the estimates of the dispersions in the rotational velocities for early-type stars in our Galaxy (Dufton et al. 2006, A&A, 457, 265) and the Magellanic Clouds (Hunter et al. 2008, A&A, 479, 541). The corrected values are π1/4 (i.e. approximately 33%) larger than those published in the original papers.Hunter, I. et al.
Fecha de publicación:
92009 -
Detection of frequency spacings in the young O-type binary HD 46149 from CoRoT photometryAims: Using the CoRoT space based photometry of the O-type binary HD 46149, stellar atmospheric effects related to rotation can be separated from pulsations, because they leave distinct signatures in the light curve. This offers the possibility of characterising and exploiting any pulsations seismologically. Methods: Combining high-quality spaceDegroote, P. et al.
Fecha de publicación:
92010 -
An Interferometric and Spectroscopic Analysis of the Multiple Star System HD 193322The star HD 193322 is a remarkable multiple system of massive stars that lies at the heart of the cluster Collinder 419. Here we report on new spectroscopic observations and radial velocities of the narrow-lined component Ab1 which we use to determine its orbital motion around a close companion Ab2 (P = 312 days) and around a distant third star Aaten Brummelaar, Theo A. et al.
Fecha de publicación:
72011 -
A Third Massive Star Component in the σ Orionis AB SystemWe report on the detection of a third massive star component in the σ Orionis AB system, traditionally considered as a binary system. The system has been monitored by the IACOB Spectroscopic Survey of Northern Massive Stars program, obtaining 23 high-resolution FIES@NOT spectra with a time span of ~2.5 years. The analysis of the radial velocitySimón-Díaz, S. et al.
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112011 -
The VLT-FLAMES Tarantula SurveyThe Tarantula survey is an ESO Large Programme which has obtained multi-epochs spectroscopy of over 800 massive stars in the 30 Dor region in the Large Magelanic Cloud. Here we briefly describe the main drivers of the survey and the observational material derived.Markova, N. et al.
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02011 -
The Ultraviolet Spectrum and Physical Properties of the Mass Donor Star in HD 226868 = Cygnus X-1We present an examination of high-resolution, ultraviolet (UV) spectroscopy from Hubble Space Telescope of the photospheric spectrum of the O-supergiant in the massive X-ray binary HD 226868 = Cyg X-1. We analyzed this and ground-based optical spectra to determine the effective temperature and gravity of the O9.7 Iab supergiant. Using non-LTE, lineCaballero-Nieves, S. M. et al.
Fecha de publicación:
82009 -
The stellar population of the star-forming region G61.48+0.09Context: We present the results of a near-infrared photometric and spectroscopic study of the star-forming region G61.48+0.09. Aims: The purpose of this study is to characterize the stellar content of the cluster and to determine its distance, extinction, age, and mass. Methods: The stellar population was studied by using color-magnitude diagramsMarín-Franch, A. et al.
Fecha de publicación:
82009 -
The Cool Supergiant Population of the Massive Young Star Cluster RSGC1We present new high-resolution near-IR spectroscopy and OH maser observations to investigate the population of cool luminous stars of the young massive Galactic cluster RSGC1. Using the 2.293 μm CO band-head feature, we make high-precision radial velocity measurements of 16 of the 17 candidate red supergiants (RSGs) identified by Figer et al. WeDavies, Ben et al.
Fecha de publicación:
42008 -
Stellar Wind Variations during the X-Ray High and Low States of Cygnus X-1We present results from Hubble Space Telescope ultraviolet spectroscopy of the massive X-ray and black hole binary system, HD 226868 = Cyg X-1. The spectra were obtained at both orbital conjunction phases in 2002 and 2003, when the system was in the X-ray high/soft state. The UV stellar wind lines suffer large reductions in absorption strength whenGies, D. R. et al.
Fecha de publicación:
52008 -
New very massive stars in Cygnus OB2Context: The compact association Cygnus OB2 is known to contain a large population of massive stars, but its total mass is currently a matter of debate. While recent surveys have uncovered large numbers of OB stars in the area around Cyg OB2, detailed study of the optically brightest among them suggests that most are not part of the associationNegueruela, I. et al.
Fecha de publicación:
82008 -
Astrophysical Parameters of LS 2883 and Implications for the PSR B1259-63 Gamma-ray BinaryOnly a few binary systems with compact objects display TeV emission. The physical properties of the companion stars represent basic input for understanding the physical mechanisms behind the particle acceleration, emission, and absorption processes in these so-called gamma-ray binaries. Here we present high-resolution and high signal-to-noiseNegueruela, Ignacio et al.
Fecha de publicación:
52011 -
The VLT-FLAMES Tarantula Survey. III. A very massive star in apparent isolation from the massive cluster R136VFTS 682 is located in an active star-forming region, at a projected distance of 29 pc from the young massive cluster R136 in the Tarantula Nebula of the Large Magellanic Cloud. It was previously reported as a candidate young stellar object, and more recently spectroscopically revealed as a hydrogen-rich Wolf-Rayet (WN5h) star. Our aim is to obtainBestenlehner, J. M. et al.
Fecha de publicación:
62011 -
The VLT-FLAMES Tarantula Survey. II. R139 revealed as a massive binary systemWe report the discovery that R139 in 30 Doradus is a massive spectroscopic binary system. Multi-epoch optical spectroscopy of R139 was obtained as part of the VLT-FLAMES Tarantula Survey, revealing a double-lined system. The two components are of similar spectral types; the primary exhibits strong C III λ4650 emission and is classified as an O6.5Taylor, W. D. et al.
Fecha de publicación:
62011 -
The VLT-FLAMES Survey of Massive StarsThe VLT-FLAMES Survey of Massive Stars was an ESO Large Programme to understand rotational mixing and stellar mass loss in different metallicity environments, in order to better constrain massive star evolution. We gathered high-quality spectra of over 800 stars in the Galaxy and in the Magellanic Clouds. A sample of this size is unprecedentedEvans, Chris et al.
Fecha de publicación:
32008 -
The nature of HH 223 from long-slit spectroscopyContext: HH 223 is a knotty, undulating nebular emission of ˜30 arcsec length found in the L723 star-forming region. It lies projected onto the largest blueshifted lobe of the quadrupolar CO outflow powered by a low-mass YSO system embedded in the core of L723. Aims: We analysed the physical conditions and kinematics along HH 223 with the aim ofLópez, R. et al.
Fecha de publicación:
52009 -
The Counterjet of HH 30: New Light on Its Binary Driving SourceWe present new [S II] images of the Herbig-Haro (HH) 30 jet and counterjet observed in 2006, 2007, and 2010 that, combined with previous data, allowed us to measure with improved accuracy the positions and proper motions of the jet and counterjet knots. Our results show that the motion of the knots is essentially ballistic, with the exception ofEstalella, Robert et al.
Fecha de publicación:
82012 -
Spectroscopic and physical parameters of Galactic O-type stars. I. Effects of rotation and spectral resolving power in the spectral classification of dwarfs and giantsContext. The modern-era spectral classification of O-stars relies on either the Walborn or the Conti-Mathys scheme. Since both of these approaches have been developed using low-quality photographic data, their application to high-quality digital data might not be straightforward and be hampered by problems and complications that have not yet beenMarkova, N. et al.
Fecha de publicación:
62011