Physics of Ionized Nebulae

    General
    Description

    The research that is being carried out by the group can be condensed into two main lines:

    1) Study of the structure, dynamics, physical conditions and chemical evolution of Galactic and extragalactic ionized nebulae through detailed analysis and modelization of their spectra. Investigation of chemical composition gradients along the disk of our Galaxy and in nearby galaxies.

    2) Determine the physical-chemical conditions of galactic planetary nebulae with bipolar geometry and nebulae around symbiotic stars. The aim is to understand the origin of bipolarity and to test theoretical models that attempt to explain nebular morphology and kinematics, with special emphasis on models with central binary stars. We will also study the implications of the evolution of binary systems in other astrophysical scenarios, such as the formation of jets, cataclysmic variables, and nova and supernova-type explosions.

    Principal investigator
    Project manager
    Collaborators
    Dr.
    A.R. López Sánchez
    Dr.
    N.C. Sterling
    Dra.
    Karla Z. Arellano Córdoba
    Dr.
    T. Hillwig
    Dr.
    M. Santander García
    Prof.
    B. Balick
    Dr.
    D. R. Gonçalves
    Dra.
    K. Kwitter
    Dr.
    A. Prsa
    1. Using EMIR/GTC spectra in the near infrared range, tellurium and bromine emission lines have been detected for the first time in two planetary nebulae. These heavy element detections in one of their places where they are formed, give us information about the abundance patterns of heavy elements owing to the r-process and the s-process.

    Related publications

    • Ionization correction factors for sodium, potassium, and calcium in planetary nebulae
      We use a large grid of photoionization models that are representative of observed planetary nebulae (PNe) to derive ionization correction factors (ICFs) for sodium, potassium, and calcium. In addition to the analytical expressions of the ICFs, we provide the range of validity where the ICFs can be safely used and an estimate of the typical
      Amayo, A. et al.

      Advertised on:

      2
      2020
      Citations
      7
    • Accretion and outflow in V404 Cyg
      We study the optical evolution of the 2015 outburst in V404 Cyg, with emphasis on the peculiar nebular phase and subsequent decay to quiescence. From the decay time-scale of the Balmer emission associated with the nebula, we measure an outflow mass Mwind ≃ 4 × 10-6 M⊙. Remarkably, this is ˜100 times larger than the accreted mass and ˜10 per cent of
      Casares, J. et al.

      Advertised on:

      9
      2019
      Citations
      21
    • Detection Limits of Exoplanetary Atmospheres with 2-m Class Telescopes
      Transmission spectroscopy is an important technique to probe the atmospheres of exoplanets. With the advent of the Transiting Exoplanet Survey Satellite (TESS) and, in the future, of the PLAnetary Transits and Oscillations of stars (PLATO), more and more transiting planets around bright stars will be found and the observing time of current large
      Kabáth, P. et al.

      Advertised on:

      8
      2019
      Citations
      12
    • Spectral analysis of the barium central star of the planetary nebula Hen 2-39
      Context. Barium stars are peculiar red giants characterized by an overabundance of the elements synthesized in the slow neutron-capture nucleosynthesis (s-process elements) along with an enrichment in carbon. These stars are discovered in binaries with white dwarf companions. The more recently formed of these stars are still surrounded by a
      Löbling, L. et al.

      Advertised on:

      4
      2019
      Citations
      5
    • A New Einstein Cross Gravitational Lens of a Lyman-break Galaxy
      We report the study of an “Einstein Cross” configuration first identified in a set of HST images by Cerny et al. Deep spectroscopic observations obtained at the Spanish 10.4 m Gran Telescopio Canarias telescope, allowed us to demonstrate the lens nature of the system, that consists of a Lyman-break galaxy (LBG), not a quasi-stellar object as is
      Bettoni, D. et al.

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      3
      2019
      Citations
      6
    • Bolometric Treatment of Irradiation Effects: General Discussion and Application to Binary Stars
      A general framework for dealing with irradiation effects in the bolometric sense—specifically, reflection with heat absorption and the consequent redistribution of the absorbed heat—for systems of astrophysical bodies where the boundaries are used as support for the description of the processes, is presented. Discussed are its mathematical and
      Horvat, M. et al.

      Advertised on:

      2
      2019
      Citations
      18
    • Co-spatial UV-optical HST/STIS spectra of six planetary nebulae: nebular and stellar properties
      This paper represents the conclusion of a project that had two main goals: (1) to investigate to what extent planetary nebulae (PNe) are chemically homogeneous; and (2) to provide physical constraints on the central star properties of each PN. We accomplished the first goal by using HST/STIS spectra to measure the abundances of seven elements in
      Miller, Timothy R. et al.

      Advertised on:

      1
      2019
      Citations
      13
    • The short orbital period binary star at the heart of the planetary nebula M 3-1★
      We present the discovery of a 3h5m orbital-period binary star at the heart of the planetary nebula M 3-1 - the shortest period photometrically variable central star known and second only to V458 Vul, in general. Combined modelling of light and radial velocity curves reveals both components to be close to Roche lobe filling, strongly indicating that
      Jones, D. et al.

      Advertised on:

      1
      2019
      Citations
      31
    • On the post-common-envelope central star of the planetary nebula NGC 2346
      The common-envelope phase is one of the most poorly understood phases of (binary) stellar evolution, in spite of its importance in the formation of a wide range of astrophysical phenomena ranging from cataclysmic variables to cosmologically important supernova Type Ia, and even recently discovered gravitational wave producing black hole mergers
      Brown, A. J. et al.

      Advertised on:

      2
      2019
      Citations
      18
    • Chemistry in the dIrr galaxy Leo A
      We present chemical abundance determinations of two H II regions in the dwarf irregular (dIrr) galaxy Leo A from Gran Telescopio Canarias (GTC) Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) long-slit spectra. Both H II regions are of low excitation and seem to be ionized by stars later than O8V spectral type. In one
      Ruiz-Escobedo, F. et al.

      Advertised on:

      11
      2018
      Citations
      6
    • Confirmation of the link between central star binarity and extreme abundance discrepancy factors in planetary nebulae
      It has recently been noted that there seems to be a strong correlation between planetary nebulae with close binary central stars and highly enhanced recombination line abundances. We present new deep spectra of seven objects known to have close binary central stars, and find that the heavy element abundances derived from recombination lines exceed
      Wesson, R. et al.

      Advertised on:

      11
      2018
      Citations
      68
    • Neutron-capture Elements in Planetary Nebulae: First Detections of Near-infrared [Te III] and [Br V] Emission Lines
      We have identified two new near-infrared (NIR) emission lines in the spectra of planetary nebulae arising from heavy elements produced by neutron-capture reactions: [Te III] 2.1019 μm and [Br V] 1.6429 μm. [Te III] was detected in both NGC 7027 and IC 418, while [Br V] was seen in NGC 7027. The observations were obtained with the medium-resolution
      Madonna, S. et al.

      Advertised on:

      7
      2018
      Citations
      18
    • Revisiting the radial abundance gradients of nitrogen and oxygen of the Milky Way
      We present spectra obtained with the 10.4 m Gran Telescopio Canarias telescope of 13 Galactic H II regions, most of them of very low ionization degree. The objects are located along the Galactic disc, with RG from 5.7 to 16.1 kpc. We determine Te([N II]) for all of them. We obtain - for the first time - a radial abundance gradient of N that is
      Esteban, C. et al.

      Advertised on:

      8
      2018
      Citations
      71
    • C/O ratios in planetary nebulae with dual-dust chemistry from faint optical recombination lines
      We present deep high-resolution (R ˜ 15 000) and high-quality UVES optical spectrophotometry of nine planetary nebulae with dual-dust chemistry. We compute physical conditions from several diagnostics. Ionic abundances for a large number of ions of N, O, Ne, S, Cl, Ar, K, Fe and Kr are derived from collisionally excited lines. Elemental abundances
      García-Rojas, J. et al.

      Advertised on:

      2
      2018
      Citations
      17
    • The planetary nebula IC 4776 and its post-common-envelope binary central star
      We present a detailed analysis of IC 4776, a planetary nebula displaying a morphology believed to be typical of central star binarity. The nebula is shown to comprise a compact hourglass-shaped central region and a pair of precessing jet-like structures. Time-resolved spectroscopy of its central star reveals a periodic radial velocity variability
      Sowicka, P. et al.

      Advertised on:

      11
      2017
      Citations
      23
    • The radial abundance gradient of oxygen towards the Galactic anti-centre
      We present deep optical spectroscopy of eight H II regions located in the anti-centre of the Milky Way. The spectra were obtained at the 10.4 m GTC and 8.2 m VLT. We determined Te([N II]) for all objects and Te([O III]) for six of them. We also included in our analysis an additional sample of 13 inner-disc Galactic H II regions from the literature
      Esteban, C. et al.

      Advertised on:

      10
      2017
      Citations
      59
    • Neutron-capture element abundances in the planetary nebula NGC 5315 from deep optical and near-infrared spectrophotometry★†
      We analyse the chemical composition of the planetary nebula (PN) NGC 5315, through high-resolution (R ∼ 40000) optical spectroscopy with Ultraviolet-Visual Echelle Spectrograph at the Very Large Telescope, and medium-resolution (R ∼ 4800) near-infrared spectroscopy with Folded-port InfraRed Echellette at Magellan Baade Telescope, covering a wide
      Madonna, S. et al.

      Advertised on:

      10
      2017
      Citations
      13
    • The kinematic behaviour of optical recombination lines and collisionally excited lines in Galactic planetary nebulae*†
      The kinematics of the plasma in 14 planetary nebulae (PNe) is analysed by measuring the expansion velocities (Vexp) of different ions as derived from their collisionally excited lines (CELs) and optical recombination lines (ORLs). Vexp is analysed as a function of the ionization potential of ions, which at a first approximation represents the
      García-Rojas, J. et al.

      Advertised on:

      11
      2017
      Citations
      15
    • Identification of Near-infrared [Se iii] and [Kr vi] Emission Lines in Planetary Nebulae
      We identify [Se iii] 1.0994 μm in the planetary nebula (PN) NGC 5315 and [Kr vi] 1.2330 μm in three PNe from spectra obtained with the Folded-Port InfraRed Echellette (FIRE) spectrometer on the 6.5 m Baade Telescope. Se and Kr are the two most widely detected neutron-capture elements in astrophysical nebulae, and can be enriched by s-process
      Sterling, N. C. et al.

      Advertised on:

      5
      2017
      Citations
      17
    • Carbon and oxygen in H II regions of the Magellanic Clouds: abundance discrepancy and chemical evolution
      We present C and O abundances in the Magellanic Clouds derived from deep spectra of H II regions. The data have been taken with the Ultraviolet-Visual Echelle Spectrograph at the 8.2-m Very Large Telescope. The sample comprises five H II regions in the Large Magellanic Cloud (LMC) and four in the Small Magellanic Cloud (SMC). We measure pure
      Domínguez-Guzmán, G. et al.

      Advertised on:

      5
      2017
      Citations
      85

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