The Potential of White Dwarf Cosmochronology
- G. Fontaine, P. Brassard, P. Bergeron
- Physics
- 1 April 2001
In the light of recent significant progress on both the observational and theoretical fronts, we review the status of white dwarf stars as cosmochronometers. These objects represent the end products…
Spectroscopic Studies of DB White Dwarfs: The Instability Strip of the Pulsating DB (V777 Herculis) Stars
- A. Beauchamp, F. Wesemael, P. Brassard
- Physics
- 10 May 1999
We have secured optical spectra for the eight currently known variable DB, or V777 Her, stars. With the help of a new generation of synthetic spectra, spectroscopic effective temperatures are derived…
A compact system of small planets around a former red-giant star
- S. Charpinet, G. Fontaine, J. Telting
- Physics, GeologyNature
- 22 December 2011
The presence of two nearly Earth-sized bodies orbiting the post-red-giant, hot B subdwarf star KIC 05807616 is reported, which may be the dense cores of evaporated giant planets that were transported closer to the star during the engulfment and triggered the mass loss necessary for the formation of the hot B subswarf.
The Pulsating White Dwarf Stars
- G. Fontaine, P. Brassard
- Physics
- 1 October 2008
We present a summary of what is currently known about the three distinct families of isolated pulsating white dwarfs. These are the GW Vir stars (He/C/O-atmosphere stars with Teff ≃ 120,000 K), the…
Cooling Sequences and Color-Magnitude Diagrams for Cool White Dwarfs with Hydrogen Atmospheres
- G. Chabrier, P. Brassard, G. Fontaine, D. Saumon
- Physics
- 26 June 2000
We present new cooling sequences, color-magnitude diagrams, and color-color diagrams for cool white dwarfs with pure hydrogen atmospheres down to an effective temperature Teff = 1500 K. We include a…
A preliminary look at the empirical mass distribution of hot B subdwarf stars
- G. Fontaine, P. Brassard, S. Charpinet, E. Green, S. Randall, V. Grootel
- Geology, Physics
- 1 March 2012
We present the results of about a decade of efforts toward building an empirical mass distribution for hot B subdwarf stars on the basis of asteroseismology. So far, our group has published detailed…
Discovery of A New Class of Pulsating Stars: Gravity-Mode Pulsators among Subdwarf B Stars
- E. Green, G. Fontaine, A. Bronowska
- Physics
- 14 October 2002
During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low-amplitude, multimode…
On the Spectral Evolution of Hot White Dwarf Stars. I. A Detailed Model Atmosphere Analysis of Hot White Dwarfs from SDSS DR12
- A. B'edard, P. Bergeron, P. Brassard, G. Fontaine
- Physics, GeologyAstrophysical Journal
- 17 August 2020
As they evolve, white dwarfs undergo major changes in surface composition, a phenomenon known as spectral evolution. In particular, some stars enter the cooling sequence with helium atmospheres (type…
Adiabatic properties of pulsating DA white dwarfs. II: Mode trapping in compositionally stratified models
- P. Brassard, G. Fontaine, F. Wesemael, C. Hansen
- Physics
- 1 May 1992
As part of a series of investigations aimed at understanding the adiabatic gravity-mode period structure of models of pulsating DA white dwarfs, we examine qualitatively and quantitatively the…
Discovery and Asteroseismological Analysis of the Pulsating sdB Star PG 0014+067
- P. Brassard, G. Fontaine, M. Billères, S. Charpinet, J. Liebert, R. Saffer
- Physics
- 20 December 2001
We report the discovery of low-amplitude, short-period, multiperiodic luminosity variations in the hot B subdwarf PG 0014+067. This star was selected as a potential target in the course of our…
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