• Evolution and Asteroseismology of Pulsating Low-Mass White Dwarfs 

      Calcaferro, L.M.; Corsico, A.H.; Althaus, L.G.; Romero, A.D.; Kepler, S.O. (2018-07)
      Many low-mass white dwarfs are being discovered in the field of our galaxy and some of them exhibit g-mode pulsations, comprising the extremely low-mass variable (ELMV) stars class. Although it is generally believed ...
    • Evolutionary and Pulsational Properties of Ultra-massive White Dwarfs. The Role of Oxygen-Neon Phase Separation. 

      De Geronimo, F.C.; Camisassa, M.E.; Corsico, A.H.; Althaus, L.G. (2018-07)
      Ultra-massive hydrogen-rich white dwarf stars are expected to harbour oxygen/neon cores resulting from semidegenerate carbon burning when the progenitor star evolves through the super asymptotic giant branch (S-AGB) ...
    • Evolutionary and pulsational properties of ultra-massive white dwarfs. The role of oxygen-neon phase separation. 

      De Gerónimo, F.C.; Camisassa, M.E.; Córsico, A.H.; Althaus, L.G. (2018-07)
      Ultra-massive hydrogen-rich white dwarfs (WDs) are expected to harbor oxygen/neon cores resulting from semi-degenerate carbon burning when the progenitor star evolves through the super asymptotic giant branch (SAGB) ...
    • An Exploration of Spotted White Dwarfs from K2 

      Reding, Joshua S.; Hermes, J. J.; Clemens, J. Christopher (2018-07)
      The Kepler K2 mission has discovered a significant population of white dwarf stars that exhibit photometric variability due to surface inhomogeneities likely related to magnetism. These “spotted” white dwarfs present ...
    • The Gaia white dwarf population within 100 pc of the Sun 

      Torres, S.; Rebassa-Mansergas, A.; Jiménez-Esteban, F.M.; Cantero, C.; Canals, P.; Skorobogatov, G.; Solano, E. (2018-07)
      The recent Gaia Data Release 2 has provided an unprecedented sample of the local white dwarf population. The high astrometric resolution and the photometry provided by Gaia allows to build a clean magnitude-color diagram ...
    • The gravitational redshift of Sirius B 

      Joyce, S.R.G.; Barstow, M.A.; Holberg, J.B.; Bond, H.E.; Casewell, S.L.; Burleigh, M.R. (2018-07)
      Previous measurements of the gravitational redshift of Sirius B have resulted in a mass estimate which is significantly larger than the mass measured from the binary orbit. We have obtained new HST observations of ...
    • High-precision atomic physics laboratories in space: White dwarfs and subdwarfs 

      Landstorfer, A.; Löbling, L.; Rauch, T.; Werner, K.; Quinet, P. (2018-07)
      Stellar atmospheres are prime laboratories to determine atomic properties of highly ionized species. Reliable opacities are crucial ingredients for the calculation of stellar atmospheres of white dwarfs and subdwarfs. ...
    • Improved and Tested: A New Generation of Cool White Dwarf Atmosphere Models 

      Blouin, S.; Dufour, P.; Allard, N.F.; Kilic, M. (2018-07)
      The photosphere of cool, helium-rich white dwarfs is notoriously tricky to model due to its fluid-like density. Using modern ab initio calculations, we have developed a new generation of atmosphere models that include ...
    • Limits on mode coherence due to a non-static convection zone 

      Montgomery, M.H.; Hermes, J. J.; Winget, D.E. (2018-07)
      The standard theory of pulsations deals with the frequencies and growth rates of infinitesimal perturbations in a stellar model. Modes which are calculated to be linearly driven should increase their amplitudes ...
    • Luminosity and cooling suppression in magnetized white dwarfs 

      Bhattacharya, M.; Mukhopadhyay, B.; Mukerjee, S. (2018-07)
      We investigate the luminosity and cooling of highly magnetized white dwarfs where cooling occurs by the diffusion of photons. We solve the magnetostatic equilibrium and photon diffusion equations to obtain the temperature ...
    • Magnetic Torques Imply Fewer Double Detonations 

      Neunteufel, P.; Yoon, S.C.; Langer, N. (2018-07)
      Binary systems composed of one helium-rich nondegenerate star and one carbon-oxygen white dwarf (He+CO) have long been considered a promising progenitor candidate for a number of astrophysical transients like archetypical ...
    • Mg line profiles for cool WD and their application in the UV 

      Gadéa, F.X.; Leininger, T.; Guillon, G.; Allard, N.F.; Blouin, S.; Dufour, P. (2018-07)
      Since last decade there have been great advances and extremely exciting results in the search and interpretation for cool DZ white dwarfs. In the formation of their spectra, the far wings of alkaline earth metals like ...
    • A New Look at Magnetic White Dwarfs 

      Hardy, F.; Dufour, P.; Jordan, S. (2018-07)
      We present a homogeneous photometric analysis of a large sample of magnetic DA white dwarfs as well as selected results from a spectrophotometric analysis of magnetic carbon-dominated atmosphere white dwarfs. We find ...
    • Numerical simulations of the convective dilution process in helium-rich white dwarfs 

      Rolland, B.; Bergeron, P.; Fontaine, G. (2018-07)
      DB and DBA white dwarfs are generally believed to be the result of a process by which a thin radiative hydrogen atmosphere floating in diffusive equilibrium on top of a helium envelope is eventually completely diluted ...
    • A Precise Radial Velocity Search for Giant Planets orbiting polluted White Dwarfs 

      Endl, M.; Williams, K.A. (2018-07)
      We present a feasibility study for extending the well-known radial velocity technique to search for planetary companions around white dwarfs. Typically, the spectra of white dwarfs contain only a few pressure-broadened ...
    • Revisiting the White Dwarf Luminosity Function from the Palomar-Green Survey 

      Bédard, A.; Bergeron, P.; Fontaine, G. (2018-07)
      We present updated atmospheric parameters for all DA, DB, and DO white dwarfs in the complete sample of the Palomar-Green survey. In particular, we perform a spectroscopic analysis of the DO stars using our new set of ...
    • Temperatures and Chemical Abundances of Accreting White Dwarfs in Cataclysmic Binaries 

      Sion, E.M.; Godon, P. (2018-07)
      We present new results on surface temperatures, and chemical abundances of accreting white dwarfs (WD) in cataclysmic and symbiotic binaries. The S-Type symbiotic system RW Hydrae contains an accreting WD with a surface ...
    • An Update on Pulsations in Accreting White Dwarfs 

      Szkody, Paula; Mukadam, Anjum (2018-07)
      Since the last white dwarf workshop, there is continuing evidence that long (hrs to days) periodicities are being found in white dwarfs that are undergoing accretion in close binary systems. Pulsation modes remain a ...
    • White dwarf collisions and the meteoritic Ne-E anomaly 

      Isern, J.; Bravo, E. (2018-07)
      The analysis of noble gases in primitive meteorites has shown the existence of anomalous isotopic abundances when compared with the average Solar System values. In particular it has been found that some graphite grains ...