• 25 years of using the spectroscopic method: where do we stand? 

      Bergeron, P.; Genest-Beaulieu, C.; Coutu, S.; Blouin, S.; Bédard, A.; Cloutier, S. (2018-07)
      The spectroscopic technique, which consists in fitting high signal-to-noise optical spectra with the predictions of state-of-the-art model atmospheres, has routinely been used for over 25 years to measure the ...
    • An Analysis of the Circumstellar Absorption of WD 1145+017 

      Fortin-Archambault, M.; Dufour, P.; Xu, S. (2018-07)
      WD 1145+017 is a white dwarf that has an actively disintegrating object in orbit and also uniquely displays circumstellar gas absorption. We present a preliminary analysis of the circumstellar absorption features present ...
    • Asteroseismological Study on PG 0112+104 with Pure and Screened Coulomb Potential 

      Chen, Y.H. (2018-07)
      With 78.7 days of observations by Kepler space telescope, Hermes et al. (2017) made a detailed mode identification on a hot DBV star PG 0112+104. In total, 11 likely m = 0 components with 5 triplets and 3 quintuplets ...
    • Blue Large-Amplitude Pulsators (BLAPs): Possible Origin, Evolutionary Status, and Nature of their Pulsations 

      Corsico, A.H.; Romero, A.D.; Althaus, L.G.; Pelisoli, I.; Kepler, S.O. (2018-07)
      The Blue Large-Amplitude Pulsators (BLAPs) constitute a new class of pulsating stars. They are hot stars with effective temperatures of Teff ~ 30000 K and surface gravities of log g ~ 4.9, that pulsate with periods ...
    • Constraining Low-Mass White Dwarf Binaries from Ellipsoidal Variations 

      Bell, K.J.; Hermes, J.J.; Kuszlewicz, J.S. (2018-07)
      Stars are stretched by tidal interactions in tight binaries, and changes to their projected areas introduce photometric variations twice per orbit. Hermes et al. (2014) utilized measurements of these ellipsoidal ...
    • Constraining the Milky Way potential with Double White Dwarfs 

      Korol, V.; Rossi, E.M.; Barausse, E. (2018-07)
      The upcoming LISA mission is the only experiment that will allow us to study the Milky Way’s structure using gravitational wave signals from Galactic double white dwarfs (DWDs). The total number of expected detections ...
    • The difficulty of finding double-degenerate progenitors of type Ia supernovae 

      Rebassa-Manserga, A.; Toonen, S.; Korol, V.; Torres, S. (2018-07)
      The double-degenerate progenitors of type Ia supernovae (SNIa) are double white dwarf binaries with a total mass near the Chandrasekhar limit and with merger timescales smaller than the Hubble time. The fact that we ...
    • Dusty Exoplanetary Debris Disks in the Single-Temperature Blackbody Plane 

      Dennihy, E.; Clemens, J.C.; Dunlap, B.H. (2018-07)
      We present a bulk sample analysis of the metal polluted white dwarfs which also host infrared bright dusty debris disks, known to be direct signatures of an active exoplanetary accretion source. We explore the relative ...
    • 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) ...
    • 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 ...