142 citations · 1.3k across the 30 of their papers we have counts for
20 papers · 1 filter
Diffusion coefficients in the envelopes of white dwarfs
R. A. Heinonen, D. Saumon, J. Daligault +3
The diffusion of elements is a key process in understanding the unusual surface composition of white dwarfs stars and their spectral evolution. The diffusion coefficients of Paquet…
A Convective Dredge-Up Model as the Origin of Hydrogen in DBA White Dwarfs
B. Rolland, P. Bergeron, G. Fontaine
We revisit the problem of the formation of DB white dwarfs, as well as the origin of hydrogen in DBA stars, using a new set of envelope model calculations with stratified and mixed…
Calibration of the mixing length theory for structures of helium-dominated atmosphere white dwarfs
Cukanovaite E., P. -E. Tremblay, B. Freytag +5
We perform a calibration of the mixing length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on…
Measurements of Physical Parameters of White Dwarfs: A Test of the Mass-Radius Relation
Antoine Bédard, Pierre Bergeron, Gilles Fontaine
We present a detailed spectroscopic and photometric analysis of 219 DA and DB white dwarfs for which trigonometric parallax measurements are available. Our aim is to compare the ph…
A Model of the Pulsating Extremely Low-Mass White Dwarf Precursor WASP 0247-25B
Alina G. Istrate, Gilles Fontaine, Christian Heuser
We present an analysis of the evolutionary and pulsation properties of the extremely low-mass white dwarf precursor (B) component of the double-lined eclipsing system WASP 0247-25.…
Just how hot are the Centauri extreme horizontal branch pulsators?
M. Latour, S. K. Randall, P. Chayer +5
Past studies based on optical spectroscopy suggest that the five Cen pulsators form a rather homogeneous group of hydrogen-rich subdwarf O stars with effective temperatures of…
The potential of asteroseismology for probing the core chemical stratification in white dwarf stars
N. Giammichele, S. Charpinet, P. Brassard +2
Context. The details of the C/O core structure in white dwarf stars has mostly remained inaccessible to the technique of asteroseismology, despite several attempts carried out in t…
Asteroseismic test of rotational mixing in low-mass white dwarfs
A. G. Istrate, G. Fontaine, A. Gianninas +4
We exploit the recent discovery of pulsations in mixed-atmosphere (He/H), extremely low-mass white dwarf precursors (ELM proto-WDs) to test the proposition that rotational mixing i…
Spectral analysis of the sdO standard star Feige 34
M. Latour, P. Chayer, E. M. Green +1
We present our current work on the spectral analysis of the hot sdO star Feige 34. We combine high S/N optical spectra and fully-blanketed non-LTE model atmospheres to derive its f…
The Montreal White Dwarf Database: a Tool for the Community
P. Dufour, S. Blouin, S. Coutu +4
We present the "Montreal White Dwarf Database" (MWDD), an accessible database with sortable/filterable table and interactive plots that will, when fully completed, allow the commun…
A NLTE analysis of the hot subdwarf O star BD+28 4211. II. The optical spectrum
M. Latour, G. Fontaine, E. M. Green +1
We present the second part of our detailed analysis of the hot sdO and spectroscopic standard star BD+28 4211, in which we focus on the optical spectrum. In the first part of our s…
Calibration of the Mixing-Length Theory for Convective White Dwarf Envelopes
P. -E. Tremblay, H. -G. Ludwig, B. Freytag +3
A calibration of the mixing-length parameter in the local mixing-length theory (MLT) is presented for the lower part of the convection zone in pure-hydrogen atmosphere white dwarfs…
Spectral analysis and abundances of the post-HB star HD 76431
V. Khalack, B. Yameogo, F. LeBlanc +4
HD76431 is a slow rotating post-HB star that shows an underabundance of helium by 0.5 dex relative to the solar value. These observational facts suggest that atomic diffusion could…
A Helium-Carbon Correlation on the Extreme Horizontal Branch in Centauri
Marilyn Latour, Suzanna K. Randall, Gilles Fontaine +3
Taking advantage of a recent FORS2/VLT spectroscopic sample of Extreme Horizontal Branch (EHB) stars in Cen, we isolate 38 spectra well suited for detailed atmospheric studies…
Improved determination of the atmospheric parameters of the pulsating sdB star Feige 48
M. Latour, G. Fontaine, E. M. Green +2
As part of a multifaceted effort to exploit better the asteroseismological potential of the pulsating sdB star Feige 48, we present an improved spectroscopic analysis of that star…
Observational Asteroseismology of Hot Subdwarf Stars with the Mont4K/Kuiper Combination at the Steward Observatory Mount Bigelow Station
G. Fontaine, E. M. Green, S. Charpinet +5
In the last few years, we have carried out several extensive observational campaigns on pulsating hot subdwarf stars using the Mont4K CCD camera attached to the 1.55 m Kuiper Teles…
A NLTE analysis of the hot subdwarf O star Bd+28 4211. I. The UV spectrum
M. Latour, G. Fontaine, P. Chayer +1
We present a detailed analysis of the UV spectrum of the calibration star Bd+28 4211 using high-quality spectra obtained with the HST and FUSE satellites. To this aim, we compare q…
Modeling the System Parameters of 2M1533+3759: A New Longer-Period Low-Mass Eclipsing sdB+dM Binary
B. -Q. For, E. M. Green, G. Fontaine +17
We present new photometric and spectroscopic observations for 2M 1533+3759 (= NSVS 07826147). It has an orbital period of 0.16177042 day, significantly longer than the 2.3--3.0 hou…
Observations and asteroseismological analysis of the rapid subdwarf B pulsator EC 09582-1137
S. K. Randall, V. Van Grootel, G. Fontaine +2
We made photometric and spectroscopic observations of the rapidly pulsating subdwarf B star EC 09582-1137 with the aim of determining the target's fundamental structural parameters…
Follow-up Observations of the Second and Third Known Pulsating Hot DQ White Dwarfs
P. Dufour, E. M. Green, G. Fontaine +3
We present follow-up time-series photometric observations that confirm and extend the results of the significant discovery made by Barlow et al.(2008) that the Hot DQ white dwarfs…