Abundancias Químicas en Estrellas

Año de inicio
2010
Unidad organizativa

Subvenciones relacionadas:

    General
    Descripción

    La espectroscopía de estrellas nos permite determinar las propiedades y composiciones químicas de las mismas. A partir de esta información para estrellas de diferente edad en la Vía Láctea es posible reconstruir la evolución química de la Galaxia, así como el origen de los elementos más pesados que el boro, forjados principalmente en los interiores estelares. También es posible estudiar la formación estelar, y la de la propia Galaxia, a través de la huella que deja el potencial Galáctico en las órbitas de las estrellas, y de las distribuciones de masa, edad y la abundancia de elementos pesados.

    La obtención de espectros con alta resolución espectral, apropiados para estudios de la composición química, requiere instrumentación sofisticada y eficiente. Esto es especialmente cierto en investigaciones en las que se necesitan extensas muestras de estrellas, que exigen observar cientos, o incluso miles de fuentes de forma simultánea. El procesado y análisis de los datos debe ser automatizado para ser igualmente eficiente.

    La interpretación de los espectros se basa en modelos físicos de las atmósferas de las estrellas, de donde se escapa la luz que observamos. Los ingredientes fundamentales para la construcción de estos modelos son la dinámica de fluidos, y las propiedades de los átomos, iones y moléculas, especialmente en lo que se refiere a sus interacciones con la radiación que proviene del interior estelar. Una vez que se tiene un modelo plausible, es posible calcular de forma detallada cómo se propaga la radiación a través de la atmósfera estelar, y el espectro emergente, para, de forma iterativa, compararlo con las observaciones y refinar el modelo.

    Este Proyecto incluye tres diferentes frentes de investigación:

    - La mejora de los modelos de atmósfera y las simulaciones de espectros estelares.

    - El desarrollo de herramientas para la obtención, reducción y el análisis de observaciones espectroscópicas, y en particular para la determinación de abundancias químicas en estrellas.

    - El diseño, preparación, y ejecución de estudios espectroscópicos de estrellas con el fin de entender a) los aspectos más relevantes de la física de las atmósferas estelares, b) la formación y evolución de las estrellas, c) el origen de los elementos químicos y d) la formación, estructura y evolución química de la Vía Láctea.

    Investigador principal
    Personal del proyecto
    Colaboradores
    Dr.
    I. Hubeny
    Dr.
    B. Castanheira
    Dr.
    M. Kilic
    Dr.
    S. Majewski
    Dr.
    H.G. Ludwig
    Dr.
    M. Cropper
    Dr.
    M. P. Ruffoni
    Dr.
    J. C. Pickering
    Dr.
    K. Cunha
    Dr.
    Andrew Cooper
    Dr.
    Boris Gaensicke
    1. Completar la instalación y pruebas de HORuS en GTC
    2. Descubrir dos nuevas estrellas con abundancias de hierro inferiores a 100.000 veces el valor solar
    3. Completar la clasificación de los espectros de APOGEE con K-means
    4. Publicar una colección completa de espectros modelo para estrellas O a M
    5. Identificar la huella de la difusión química en las atmósferas de estrellas del cúmulo M67

    Publicaciones relacionadas

    • The Open Cluster Chemical Abundances and Mapping Survey. IV. Abundances for 128 Open Clusters Using SDSS/APOGEE DR16
      The Open Cluster Chemical Abundances and Mapping (OCCAM) survey aims to constrain key Galactic dynamical and chemical evolution parameters by the construction of a large, comprehensive, uniform, infrared-based spectroscopic data set of hundreds of open clusters. This fourth contribution from the OCCAM survey presents analysis using Sloan Digital
      Donor, John et al.

      Fecha de publicación:

      5
      2020
      Número de citas
      115
    • The Extreme CNO-enhanced Composition of the Primitive Iron-poor Dwarf Star J0815+4729
      We present an analysis of high-resolution Keck/HIRES spectroscopic observations of J0815+4729, an extremely carbon-enhanced, iron-poor dwarf star. These high-quality data allow us to derive a metallicity of [Fe/H] = −5.49 ± 0.14 from the three strongest Fe i lines and to measure a high [Ca/Fe] = 0.75 ± 0.14. The large carbon abundance of A(C) = 7
      González Hernández, Jonay I. et al.

      Fecha de publicación:

      1
      2020
      Número de citas
      15
    • Stellar Characterization of M Dwarfs from the APOGEE Survey: A Calibrator Sample for M-dwarf Metallicities
      We present spectroscopic determinations of the effective temperatures, surface gravities, and metallicities for 21 M dwarfs observed at high resolution (R ∼ 22,500) in the H band as part of the Sloan Digital Sky Survey (SDSS)-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. The atmospheric parameters and metallicities are
      Souto, Diogo et al.

      Fecha de publicación:

      2
      2020
      Número de citas
      36
    • Stellar atmospheric parameters of FGK-type stars from high-resolution optical and near-infrared CARMENES spectra
      With the purpose of assessing classic spectroscopic methods on high-resolution and high signal-to-noise ratio spectra in the near-infrared wavelength region, we selected a sample of 65 F-, G-, and K-type stars observed with CARMENES, the new, ultra-stable, double-channel spectrograph at the 3.5 m Calar Alto telescope. We computed their stellar
      Marfil, E. et al.

      Fecha de publicación:

      3
      2020
      Número de citas
      17
    • Signatures of the Galactic bar in high-order moments of proper motions measured by Gaia
      Our location in the Milky Way provides an exceptional opportunity to gain insight on the galactic evolution processes, and complement the information inferred from observations of external galaxies. Since the Milky Way is a barred galaxy, the study of motions of individual stars in the bulge and disc is useful to understand the role of the bar. The
      Palicio, Pedro A. et al.

      Fecha de publicación:

      2
      2020
      Número de citas
      2
    • The Pristine Survey - VIII. The metallicity distribution function of the Milky Way halo down to the extremely metal-poor regime
      The Pristine survey uses narrow-band photometry to derive precise metallicities down to the extremely metal-poor regime ( [Fe/H] < -3), and currently consists of over 4 million FGK-type stars over a sky area of ̃ 2500 deg^2. We focus our analysis on a subsample of ̃80 000 main-sequence turn-off stars with heliocentric distances between 6 and 20 kpc
      Youakim, K. et al.

      Fecha de publicación:

      3
      2020
      Número de citas
      55
    • Metallicity and α-Element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE
      Using 3D positions and kinematics of stars relative to the Sagittarius (Sgr) orbital plane and angular momentum, we identify 166 Sgr stream members observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) that also have Gaia DR2 astrometry. This sample of 63/103 stars in the Sgr trailing/leading arm is combined with an APOGEE
      Hayes, Christian R. et al.

      Fecha de publicación:

      1
      2020
      Número de citas
      60
    • A detailed non-LTE analysis of LB-1: Revised parameters and surface abundances
      Context. It has recently been proposed that LB-1 is a binary system at 4 kpc consisting of a B-type star of 8 M ☉ and a massive stellar black hole (BH) of 70 M ☉. This finding challenges our current theories of massive star evolution and formation of BHs at solar metallicity. Aims: Our objective is to derive the effective temperature, surface
      Simón-Díaz, S. et al.

      Fecha de publicación:

      2
      2020
      Número de citas
      30
    • ESPRESSO highlights the binary nature of the ultra-metal-poor giant HE 0107-5240
      Context. The vast majority of the known stars of ultra low metallicity ([Fe/H] < -4.5) are known to be enhanced in carbon, and belong to the "low-carbon band" (A(C) = log(C/H)+12 ≤ 7.6). It is generally, although not universally, accepted that this peculiar chemical composition reflects the chemical composition of the gas cloud out of which these
      Bonifacio, P. et al.

      Fecha de publicación:

      1
      2020
      Número de citas
      6
    • Physical parameters of red supergiants in dwarf irregular galaxies in the Local Group
      Context. Increasing the statistics of evolved massive stars in the Local Group enables investigating their evolution at different metallicities. During the late stages of stellar evolution, the physics of some phenomena, such as episodic and systematic mass loss, are not well constrained. For example, the physical properties of red supergiants
      Britavskiy, N. E. et al.

      Fecha de publicación:

      11
      2019
      Número de citas
      10
    • Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code - II. The Southern clusters and overview
      We investigate the Fe, C, N, O, Mg, Al, Si, K, Ca, Ce, and Nd abundances of 2283 red giant stars in 31 globular clusters from high-resolution spectra observed in both the northern and Southern hemisphere by the SDSS-IV APOGEE-2 survey. This unprecedented homogeneous data set, largest to date, allows us to discuss the intrinsic Fe spread, the shape
      Mészáros, Szabolcs et al.

      Fecha de publicación:

      2
      2020
      Número de citas
      112
    • The Pristine survey - VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates
      We present the results of a 3-yr long, medium-resolution spectroscopic campaign aimed at identifying very metal-poor stars from candidates selected with the CaHK, metallicity-sensitive Pristine survey. The catalogue consists of a total of 1007 stars, and includes 146 rediscoveries of metal-poor stars already presented in previous surveys, 707 new
      Aguado, David S. et al.

      Fecha de publicación:

      12
      2019
      Número de citas
      67
    • IMF radial gradients in most massive early-type galaxies
      Using new long-slit spectroscopy obtained with X-Shooter at ESO-VLT, we study, for the first time, radial gradients of optical and near-infrared initial mass function (IMF)-sensitive features in a representative sample of galaxies at the very high mass end of the galaxy population. The sample consists of seven early-type galaxies (ETGs) at z ̃ 0.05
      La Barbera, F. et al.

      Fecha de publicación:

      11
      2019
      Número de citas
      51
    • Machine learning in APOGEE. Identification of stellar populations through chemical abundances
      Context. The vast volume of data generated by modern astronomical surveys offers test beds for the application of machine-learning. In these exploratory applications, it is important to evaluate potential existing tools and determine those that are optimal for extracting scientific knowledge from the available observations. Aims: We explore the
      Garcia-Dias, Rafael et al.

      Fecha de publicación:

      9
      2019
      Número de citas
      13
    • The Gaia-ESO survey: Calibrating a relationship between age and the [C/N] abundance ratio with open clusters
      Context. In the era of large high-resolution spectroscopic surveys such as Gaia-ESO and APOGEE, high-quality spectra can contribute to our understanding of the Galactic chemical evolution by providing abundances of elements that belong to the different nucleosynthesis channels, and also by providing constraints to one of the most elusive
      Casali, G. et al.

      Fecha de publicación:

      9
      2019
      Número de citas
      55
    • H-band discovery of additional second-generation stars in the Galactic bulge globular cluster NGC 6522 as observed by APOGEE and Gaia
      We present an elemental abundance analysis of high-resolution spectra for five giant stars spatially located within the innermost regions of the bulge globular cluster NGC 6522 and derive Fe, Mg, Al, C, N, O, Si, and Ce abundances based on H-band spectra taken with the multi-object APOGEE-north spectrograph from the SDSS-IV Apache Point Observatory
      Fernández-Trincado, J. G. et al.

      Fecha de publicación:

      7
      2019
      Número de citas
      39
    • ExoMol molecular line lists - XXXIII. The spectrum of Titanium Oxide
      Accurate line lists are crucial for correctly modelling a variety of astrophysical phenomena, including stellar photospheres and the atmospheres of extrasolar planets. This paper presents a new line database TOTO for the main isotopologues of titanium oxide (TiO): ^{46}Ti^{16}O, ^{47}Ti^{16}O, ^{48}Ti^{16}O, ^{49}Ti^{16}O, and ^{50}Ti^{16}O. The ^
      McKemmish, Laura K. et al.

      Fecha de publicación:

      9
      2019
      Número de citas
      182
    • Stellar spectral models compared with empirical data
      The empirical MILES stellar library is used to test the accuracy of three different, state-of-the-art, theoretical model libraries of stellar spectra. These models are widely used in the literature for stellar population analysis. A differential approach is used so that responses to elemental abundance changes are tested rather than absolute levels
      Knowles, A. T. et al.

      Fecha de publicación:

      6
      2019
      Número de citas
      9
    • Chemical analysis of CH stars - III. Atmospheric parameters and elemental abundances
      Elemental abundances of CH stars can provide observational constraints for theoretical studies on the nucleosynthesis and evolution of low- and intermediate-mass stars. However, available abundance data in literature are quite scanty. In our pursuit to generate a homogeneous data base of elemental abundances of CH stars we have performed a detailed
      Purandardas, M. et al.

      Fecha de publicación:

      7
      2019
      Número de citas
      22
    • High-resolution spectroscopy of Boyajian's star during optical dimming events
      Boyajian's star is an apparently normal main-sequence F-type star with a very unusual light curve. The dipping activity of the star, discovered during the Kepler mission, presents deep, asymmetric, and aperiodic events. Here we present high-resolution spectroscopic follow-up during some dimming events recorded post-Kepler observations, from ground
      Martínez González, M. J. et al.

      Fecha de publicación:

      6
      2019
      Número de citas
      3

    Charlas relacionadas

    No se han encontrado charlas relacionadas.

    Congresos relacionados

    No se han encontrado congresos relacionados.
    Proyectos relacionados
    banco óptico
    HORuS - High Optical Resolution Spectrograph
    Espectrógrafo de alta resolución en operación en el Gran Telescopio Canarias (GTC) de 10m. usando componentes del espectrógrafo UES, utilizado en el Telescopio William Herschel (WHT) de 4.2 m. entre los años 1992 y 2001.
    Carlos
    Allende Prieto
    Gran Telescopio Canarias (GTC)
    SEVERO OCHOA 2016 - 2019
    El Gobierno español concede la Acreditación como Centro de Excelencia Severo Ochoa con el fin de reconocer, premiar y promover la investigación científica de alto nivel en los centros y unidades españoles que tengan un alto nivel de excelencia en el ámbito internacional. Los objetivos específicos del Programa Severo Ochoa son: - Mejorar la
    Rafael
    Rebolo López