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Ara es mostren els items 1-20 de 29

    • 8.9 hr rotation in the partly burnt runaway stellar remnant LP 40-365 (GD 492) 

      Hermes, J. J.; Putterman, Odelia; Hollands, M.; Wilson, David J.; Swan, Andrew; Raddi, Roberto; Shen, Ken J.; Gänsicke, Boris T. (2021-06-07)
      Article
      Accés obert
      We report the detection of 8.914 hr variability in both optical and ultraviolet light curves of LP 40-365 (also known as GD 492), the prototype for a class of partly burnt runaway stars that have been ejected from a binary ...

    • A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation 

      Camisassa, María Eugenia; Torres Gil, Santiago; Hollands, Mark; Koester, Detlev; Raddi, Roberto; Althaus, Leandro G.; Rebassa Mansergas, Alberto (EDP Sciences, 2023-06-01)
      Article
      Accés obert
      Context. The high-quality photometric and astrometric capabilities of the ESA Gaia space mission have revealed a bifurcation of the white dwarf sequence on the color magnitude diagram with two branches: A and B. While the ...

    • Blue extreme disk-runaway stars with Gaia EDR3 

      Irrgang, Andreas; Dimpel, Markus; Heber, Ulrich; Raddi, Roberto (EDP Sciences, 2021-02-01)
      Article
      Accés obert
      Since the discovery of hypervelocity stars in 2005, it has been widely believed that only the disruption of a binary system by a supermassive black hole at the Galactic center (GC), that is, the so-called Hills mechanism, ...

    • Can we reveal the core-chemical composition of ultra-massive white dwarfs through their magnetic fields? 

      Camisassa, María Eugenia; Raddi, Roberto; Althaus, Leandro G.; Isern Vilaboy, Jordi; Rebassa Mansergas, Alberto; Torres, Santiago; Córsico, Alejandro H.; Korre, Lydia (Oxford University Press, 2022-10-01)
      Article
      Accés obert
      Ultra-massive white dwarfs (1.05M¿ . MWD) are particularly interesting objects that allow us to study extreme astrophysical phenomena such as type Ia supernovae explosions and merger events. Traditionally, ultra-massive ...

    • Carbon-oxygen ultra-massive white dwarfs in general relativity 

      Althaus, Leandro G.; Corsico, Alejandro H.; Camisassa, María Eugenia; Torres Gil, Santiago; Gil Pons, Pilar; Rebassa Mansergas, Alberto; Raddi, Roberto (Oxford University Press, 2023-08-01)
      Article
      Accés obert
      We employ the La Plata stellar evolution code, lpcode, to compute the first set of constant rest-mass carbon–oxygen ultra-massive white dwarf evolutionary sequences for masses higher than 1.29 M¿ that fully take into account ...

    • Forever young white dwarfs: When stellar ageing stops 

      Camisassa, María Eugenia; Althaus, Leandro G.; Torres Gil, Santiago; Córsico, Alejandro H.; Rebassa Mansergas, Alberto; Tremblay, P. E.; Cheng, Sihao; Raddi, Roberto (EDP Sciences, 2021-05-01)
      Article
      Accés obert
      White dwarf stars are the most common end point of stellar evolution. The ultramassive white dwarfs are of special interest as they are related to type Ia supernovae explosions, merger events, and fast radio bursts. ...

    • Gaia 0007-1605: an old triple system with an inner brown dwarf-white dwarf binary and an outer white dwarf companion 

      Rebassa Mansergas, Alberto; Torres Gil, Santiago; Raddi, Roberto (Institute of Physics (IOP), 2022-03-15)
      Article
      Accés obert
      We identify Gaia 0007–1605 A,C as the first inner brown dwarf–white dwarf binary of a hierarchical triple system in which the outer component is another white dwarf (Gaia 0007–1605 B). From optical/near-infrared spectroscopy ...

    • Gaia white dwarfs within 40 pc – I. Spectroscopic observations of new candidates 

      Tremblay, P. E.; Hollands, M.; Izquierdo Tugas, Pere; Gänsicke, Boris T.; Koester, D.; Brown, W J; Hermes, J. J.; Kleinman, Scot J.; Manser, C. J.; Marsh, Thomas R.; Schreiber, Mathias R.; Silvotti, R.; Rebassa Mansergas, Alberto; Raddi, Roberto (Oxford University Press, 2020-09-01)
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      Accés obert
      Realitzat a/amb:   University of Warwick / Universidad de La Laguna / Universitat Christian Albrecht de Kiel
      We present a spectroscopic survey of 230 white dwarf candidates within 40 pc of the Sun from the William Herschel Telescope and Gran Telescopio Canarias. All candidates were selected from Gaia Data Release 2 (DR2) and in ...

    • Hot white dwarf candidates from the IGAPS-GALEX cross-match 

      Gómez Muñoz, Marco A.; Sabin, Laurence; Raddi, Roberto; Wells, Robert D. (Oxford University Press, 2022-08-01)
      Article
      Accés obert
      White dwarf (WD) stars are often associated with the central stars of planetary nebulae (CSPNe) on their way to the cooling track. A large number of WD star candidates have been identified; thanks to optical large-scale ...

    • IGAPS: the merged IPHAS and UVEX optical surveys of the northern Galactic plane 

      Monguió Montells, Maria; Greimel, Robert; Drew, Janet E.; Barentsen, Geert; Gänsicke, Boris T.; Hollands, M.; Manser, C. J.; Rodríguez Gil, Pablo; Scaringi, Simone; Verbeek, Kevin; Wright, Nicholas; Eislöffel, Jochen; Sabin, Laurence; Vink, J; Raddi, Roberto (EDP Sciences, 2020-06)
      Article
      Accés obert
      The INT Galactic Plane Survey (IGAPS) is the merger of the optical photometric surveys, IPHAS and UVEX, based on data from the Isaac Newton Telescope (INT) obtained between 2003 and 2018. Here, we present the IGAPS point ...

    • Kinematic properties of white dwarfs. Galactic orbital parameters and age-velocity dispersion relation 

      Raddi, Roberto; Torres Gil, Santiago; Rebassa Mansergas, Alberto; Camisassa, María Eugenia; Koester, Detlev; Gentile Fusillo, N. P.; Tremblay, P. E.; Dimpel, Markus; Heber, Ulrich; Maldonado, Jesús (EDP Sciences, 2022-01-27)
      Article
      Accés restringit per política de l'editorial
      Context. Kinematic and chemical tagging of stellar populations have both revealed much information on the past and recent history of the Milky Way, including its formation history, merger events, and mixing of populations ...

    • Main-sequence companions to white dwarfs - II. The age-activity-rotation relation from a sample of Gaia common proper motion pairs 

      Rebassa Mansergas, Alberto; Maldonado, Jesús; Raddi, Roberto; Torres Gil, Santiago; Hoskin, Matthew; Cunningham, Tim; Hollands, Mark; Ren, Juanjuan; Gänsicke, Boris T.; Tremblay, P. E.; Camisassa, María Eugenia (Oxford University Press, 2023-10-06)
      Article
      Accés obert
      Magnetic activity and rotation are related to the age of low-mass main-sequence stars. To further constrain these relations, we study a sample of 574 main-sequence stars members of common proper motion pairs with white ...

    • Mode identification in three pulsating hot subdwarfs observed with TESS satellite 

      Raddi, Roberto (Oxford University Press, 2020-07-01)
      Article
      Accés obert
      We report on the detection of pulsations of three pulsating subdwarf B stars observed by the TESS satellite and our results of mode identification in these stars based on an asymptotic period relation. SB 459 (TIC 067584818), ...

    • Non-local thermodynamic equilibrium spectral analysis of five hot, hydrogen-deficient pre-white dwarfs 

      Werner, Klaus; Reindl, Nicole; Dorsch, Matti; Geier, Stephan; Munari, Ulisse; Raddi, Roberto (EDP Sciences, 2022-02-01)
      Article
      Accés obert
      Hot, compact, hydrogen-deficient pre-white dwarfs (pre-WDs) with effective temperatures of Teff > 70,000 K and a surface gravity of 5.0 < log g < 7.0 are rather rare objects despite recent and ongoing surveys. It is believed ...

    • Perfecting our set of spectrophotometric standard DA white dwarfs 

      Calamida, Annalisa; Matheson, Thomas; Olszewski, Edward W.; Saha, Abhijit; Axelrod, Tim; Shanahan, Clare; Holberg, Jay; Points, Sean; Narayan, Gautham; Malanchev, Konstantin; Ridden Harper, Ryan; Gentile Fusillo, Nicola; Raddi, Roberto; Bohlin, Ralph; Rest, Armin (Institute of Physics (IOP), 2022-11-01)
      Article
      Accés obert
      We verified for photometric stability a set of DA white dwarfs with Hubble Space Telescope magnitudes from thenear-ultraviolet to the near-infrared and ground-based spectroscopy by using time-spaced observations from theLas ...

    • Runaway blue main-sequence stars at high Galactic latitudes: Target selection with Gaia and spectroscopic identification 

      Raddi, Roberto; Irrgang, Andreas; Heber, Ulrich; Schneider, David; Kreuzer, Simon (EDP Sciences, 2021-01-26)
      Article
      Accés obert
      Context. The ESA Gaia mission is a remarkable tool for stellar population analysis through its accurate Hertzsprung–Russell diagram. Its precise astrometry has propelled detailed kinematic studies of the Milky Way and the ...

    • SDSS¿J124043.01+671034.68: the partially burned remnant of a low-mass white dwarf that underwent thermonuclear ignition? 

      Gänsicke, Boris T.; Koester, D.; Raddi, Roberto; Toloza, Odette; Kepler, S.O. (Oxford University Press, 2020-08-21)
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      Accés obert
      The white dwarf SDSS¿J124043.01+671034.68 (SDSS¿J1240+6710) was previously found to have an oxygen-dominated atmosphere with significant traces of neon, magnesium, and silicon. A possible origin via a violent late thermal ...

    • Serendipitous discovery of a dusty disc around WDJ181417.84-735459.83 

      González Egea, E.; Raddi, Roberto; Koester, D.; Rogers, L. K.; Marocco, F.; Cooper, W. J.; Beamin, J. C.; Burningham, B.; Day-Jones, A.; Forbrich, J.; Pinfield, D. J. (Oxford University Press, 2021-03)
      Article
      Accés obert
      Spectroscopic observations of white dwarfs reveal that many of them are polluted by exoplanetary material, whose bulk composition can be uniquely probed this way. We present a spectroscopic and photometric analysis of the ...

    • Structure and evolution of ultra-massive white dwarfs in general relativity 

      Althaus, Leandro G.; Camisassa, María Eugenia; Torres Gil, Santiago; Battich, Tiara; Córsico, Alejandro H.; Rebassa Mansergas, Alberto; Raddi, Roberto (EDP Sciences, 2022-12-01)
      Article
      Accés obert
      Ultra-massive white dwarfs (M? & 1.05M ) are of utmost importance in view of the role they play in type Ia supernovae explosions, merger events, the existence of high magnetic field white dwarfs, and the physical processes ...

    • TESS first look at evolved compact pulsators: Known ZZ Ceti stars of the southern ecliptic hemisphere as seen by TESS 

      Raddi, Roberto (EDP Sciences, 2020-06-01)
      Article
      Accés obert
      Context. We present our findings on 18 previously known ZZ Ceti stars observed by the TESS space telescope in 120 s cadence mode during the survey observation of the southern ecliptic hemisphere. Aims. We focus on the ...