Now showing items 1-12 of 12

    • An asteroseismic constraint on the mass of the axion from the period drift of the pulsating da white dwarf star L19-2 

      Córsico, Alejandro H.; Romero, Alejandra Daniela; Althaus, Leandro G.; García-Berro Montilla, Enrique; Isern Vilaboy, Jordi; Kepler, S.O.; Miller Bartolami, Marcelo M.; Sullivan, Denis J. (2016-07-01)
      Article
      Open Access
      We employ an asteroseismic model of L19-2, a relatively massive (Msstarf ~ 0.75 M¿) and hot (Teff ~ 12 100 K) pulsating DA (H-rich atmosphere) white dwarf star (DAV or ZZ Ceti variable), and use the observed values of the ...
    • Constraining the neutrino magnetic dipole moment from white dwarf pulsations 

      Corsico, Alejandro H.; Althaus, Leandro G.; Miller Bartolami, Marcelo M.; Kepler, S.O.; García-Berro Montilla, Enrique (2014-08-01)
      Article
      Open Access
      Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models ...
    • Effects of Ne-22 sedimentation and metallicity on the local 40 pc white dwarf luminosity function 

      Tononi García, Jordi; Torres Gil, Santiago; García-Berro Montilla, Enrique; Camisassa, María E.; Althaus, Leandro G.; Rebassa Mansergas, Alberto (EDP Sciences, 2019-08-06)
      Article
      Open Access
      We analyzed the effect of the sedimentation of 22Ne on the local white dwarf luminosity function by studying scenarios under different Galactic metallicity models. Methods. We use an advanced population synthesis code based ...
    • Gaia DR2 white dwarfs in the Hercules stream 

      Torres Gil, Santiago; Cantero, Carles; Camisassa, María E.; Antoja, T.; Rebassa Mansergas, Alberto; Althaus, Leandro G.; Thelemaque, Thomas; Canovas Cabrera, Héctor (EDP Sciences, 2019-09-01)
      Article
      Open Access
      We analyzed the velocity space of the thin- and thick-disk Gaia white dwarf population within 100 pc by searching for signatures of the Hercules stellar stream. We aimed to identify objects belonging to the Hercules stream, ...
    • Is the central binary system of the planetary nebula Henize 2-428 a type Ia supernova progenitor? 

      García-Berro Montilla, Enrique; Soker, Noam; Althaus, Leandro G.; Ribas Canudas, Ignasi; Morales Peralta, Juan Carlos (2016-05-01)
      Article
      Open Access
      We critically discuss the recent observations of the binary system at the center of the bipolar planetary nebula Henize 2-428. We find that the proposed explanation of two equal-mass degenerate objects with a total mass ...
    • Revisiting the luminosity function of single halo white dwarfs 

      Cojocaru, Elena Ruxandra; Torres Gil, Santiago; Althaus, Leandro G.; Isern Vilaboy, Jordi; García-Berro Montilla, Enrique (EDP Sciences, 2015-09-01)
      Article
      Open Access
      Context. White dwarfs are the fossils left by the evolution of low- and intermediate-mass stars, and have very long evolutionary timescales. This allows us to use them to explore the properties of old populations, like the ...
    • The effect of 22Ne diffusion in the evolution and pulsational properties of white dwarfs with solar metallicity prgenitors 

      Camisassa, Maria E; Althaus, Leandro G.; Corsico, Alejandro H.; Vinyoles, Núria; Serenelli, Aldo M.; Isem, Jordi; Miller Bertolami, Marcelo M; García-Berro Montilla, Enrique (Institute of Physics (IOP), 2016-06-01)
      Article
      Open Access
      © 2016. The American Astronomical Society. All rights reserved. Because of the large neutron excess of 22Ne, sedimentation of this isotope occurs rapidly in the interior of white dwarfs. This process releases an additional ...
    • The evolution of white dwarfs resulting from helium-enhanced, low-metallicity progenitor stars 

      Althaus, Leandro G.; de Geronimo, Francisco; Córsico, Alejandro H.; Torres Gil, Santiago; García-Berro Montilla, Enrique (EDP Sciences, 2017-01-01)
      Article
      Open Access
      Context. Some globular clusters host multiple stellar populations with different chemical abundance patterns. This is particularly true for ¿ Centauri, which shows clear evidence of a helium-enriched subpopulation characterized ...
    • The white dwarf cooling sequence of 47 Tucanae 

      García-Berro Montilla, Enrique; Torres Gil, Santiago; Althaus, Leandro G.; Miller Bartolami, Marcelo M. (2014-11)
      Article
      Open Access
      Context. 47 Tucanae is one of the most interesting, well-observed, and theoretically studied globular clusters. This allows us to determine the reliability of our understanding of white dwarf cooling sequences, to compare ...
    • The white dwarf population of NGC 6397 

      Torres Gil, Santiago; García-Berro Montilla, Enrique; Althaus, Leandro G.; Camisassa, Maria E (2015-09-01)
      Article
      Open Access
      Context. NGC 6397 is one of the most interesting, well-observed, and most thoroughly theoretically studied globular clusters. The existing wealth of observations allows us to study the reliability of the theoretical white ...
    • Updated evolutionary sequences for hydrogen-deficient white dwarfs 

      Camisassa, Maria E; Althaus, Leandro G.; Rohrmann, René D.; García-Berro Montilla, Enrique; Torres Gil, Santiago; Corsico, Alejandro H.; Wachlin, Felipe C. (Institute of Physics (IOP), 2017-04-10)
      Article
      Open Access
      We present a set of full evolutionary sequences for white dwarfs with hydrogen-deficient atmospheres. We take into account the evolutionary history of the progenitor stars, all the relevant energy sources involved in the ...
    • White dwarf evolutionary sequences for low-metallicity progenitors: The impact of third dredge-up 

      Althaus, Leandro G.; Camisassa, Maria E; Miller Bertolami, Marcelo M; Corsico, Alejandro H.; García-Berro Montilla, Enrique (2015-04-01)
      Article
      Open Access
      Context. White dwarfs are nowadays routinely used as reliable cosmochronometers, allowing several stellar populations to be dated.; Aims. We present new white dwarf evolutionary sequences for low-metallicity progenitors. ...