Publications (26)
Asteroseismology of the ZZ Ceti star KUV 08368+4026
C. Li, J. -N. Fu, G. Vauclair +5
Asteroseismology is a unique tool to explore the internal structure of stars through both observational and theoretical research. The internal structure of pulsating hydrogen shell…
Precise determination of stellar parameters of the ZZ Ceti and DAZ white dwarf GD 133 through asteroseismology
J. -N. Fu, G. Vauclair, J. Su +15
An increasing number of white dwarf stars show atmospheric chemical composition polluted by heavy elements accreted from debris disk material. The existence of such debris disks st…
Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234
WET Collaboration, D. J. Sullivan, T. S. Metcalfe +22
We present the analysis of a total of 177h of high-quality optical time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC 20058-5234. The bulk of the observ…
The pulsation modes of the pre-white dwarf PG 1159-035
J. E. S. Costa, S. O. Kepler, D. E. Winget +74
PG 1159-035, a pre-white dwarf with T_eff=140,000 K, is the prototype of both two classes: the PG1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-0…
Empirical Determination of Convection Parameters in White Dwarfs I : Whole Earth Telescope Observations of EC14012-1446
J. L. Provencal, M. H. Montgomery, A. Kanaan +55
We report on analysis of 308.3 hrs of high speed photometry targeting the pulsating DA white dwarf EC14012-1446. The data were acquired with the Whole Earth Telescope (WET) during…
Precise Modeling of the Exoplanet Host Star and CoRoT Main Target HD 52265
M. E. Escobar, S. Théado S. Vauclair, J. Ballot +8
This paper presents a detailed and precise study of the characteristics of the Exoplanet Host Star and CoRoT main target HD 52265, as derived from asteroseismic studies. The result…
Dilution of accreted planetary matter in hot DA white dwarfs according to their mass
M. Deal, S. Vauclair, S. Charpinet +1
A large proportion of observed white dwarfs (WDs) show evidence of debris disks, remnants of the former planetary systems, and/or signatures of heavy elements in their atmospheres,…
Understanding the Cool DA White Dwarf, G29-38
S. J. Kleinman, R. E. Nather, D. E. Winget +37
The white dwarfs are promising laboratories for the study of cosmochronology and stellar evolution. Through observations of the pulsating white dwarfs, we can measure their interna…
2006 Whole Earth Telescope Observations of GD358: A New Look at the Prototype DBV
J. L. Provencal, M. H. Montgomery, A. Kanaan +53
We report on the analysis of 436.1 hrs of nearly continuous high-speed photometry on the pulsating DB white dwarf GD358 acquired with the Whole Earth Telescope (WET) during the 200…
Abell 43: Longest period Planetary Nebula Nucleus variable
J. -E. Solheim, G. Vauclair, A. S. Mukadam +2
Based on 24h high speed photometry of the hybrid PG 1159 star Abell 43, we have detected 6 sighificant pulsations with periods between 2380 s and 6075 s. A short (4h) run on the al…
ABELL 43 a second pulsating "hybrid PG 1159 star"
G. Vauclair, J. -E. Solheim, R. Ãstensen
We report observations of the planetary nebula nucleus Abell 43, obtained at the 2.5m Nordic Optical Telescope, which shows that it is a pulsator. Abell 43, a "hybrid-PG 1159" type…
The Everchanging Pulsating White Dwarf GD358
S. O. Kepler, R. E. Nather, D. E. Winget +43
We report 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23rd to June 8th, 2…
Evidence of Resonant Mode Coupling in the Pulsating DB White Dwarf Star KIC 08626021
W. Zong, S. Charpinet, G. Vauclair
The Kepler spacecraft provides new opportunities to search for long term frequency and amplitude modulations of oscillation modes in pulsating stars. We ana- lyzed nearly two years…
New simulations of accreting DA white dwarfs: inferring accretion rates from the surface contamination
F. C. Wachlin, G. Vauclair, S. Vauclair +1
A non negligible fraction of white dwarf stars show the presence of heavy elements in their atmospheres. The most accepted explanation for this contamination is the accretion of ma…
Importance of fingering convection for accreting white dwarfs in the framework of full evolutionary calculations: the case of the hydrogen-rich white dwarfs GD133 and G29-38
F. C. Wachlin, G. Vauclair, S. Vauclair +1
A large fraction of white dwarf stars shows photospheric chemical composition polluted by heavy elements accreted from a debris disk. Such debris disks result from the tidal disrup…
HD 51106 and HD 50747: an ellipsoidal binary and a triple system observed with CoRoT
N. Dolez, S. Vauclair, E. Michel +13
We present an analysis of the observations of HD 51106 and HD 50747 by the satellite CoRoT, obtained during its initial run, and of the spectroscopic preparatory observations. AIMS…
Asteroseismology of the exoplanet-host F-type star 94 Ceti : impact of atomic diffusion on the stellar parameters
M. Deal, M. E. Escobar, S. Vauclair +3
A precision of order one percent is needed on the parameters of exoplanet-hosts stars in order to correctly characterize the planets themselves. This will be achieved by asteroseis…
Accretion from debris disks onto white dwarfs : Fingering (thermohaline) instability and derived accretion rates
M. Deal, S. Deheuvels, G. Vauclair +2
Recent observations of a large number of DA and DB white dwarfs show evidence of debris disks, which are the remnants of old planetary systems. The infrared excess detected with \e…
Asteroseismology of the ZZ Ceti star HS 0507+0434B
J. -N. Fu, N. Dolez, G. Vauclair +14
The pulsating DA white dwarfs (ZZ Ceti stars) are -mode non-radial pulsators. Asteroseismology provides strong constraints on their global parameters and internal structure. Sin…
Accurate p-mode measurements of the G0V metal-rich CoRoT target HD 52265
J. Ballot, L. Gizon, R. Samadi +27
The star HD 52265 is a G0V metal-rich exoplanet-host star observed in the seismology field of the CoRoT space telescope from November 2008 to March 2009. The satellite collected 11…
Amplitude and frequency variations of oscillation modes in the pulsating DB white dwarf star KIC~08626021: The likely signature of nonlinear resonant mode coupling
W. Zong, S. Charpinet, G. Vauclair +2
Aims. We use the Kepler data accumulated on the pulsating DB white dwarf KIC 08626021 to explore in detail the stability of its oscillation modes, searching in particular for evide…
The exoplanet-host star iota Horologii: an evaporated member of the primordial Hyades cluster
S. Vauclair, M. Laymand, F. Bouchy +4
We show that the exoplanet-host star iota Horologii, alias HD17051, which belongs to the so-called Hyades stream, was formed within the primordial Hyades stellar cluster and has ev…
He white dwarfs with large H contamination: Convective mixing or accretion?
F. C. Wachlin, G. Vauclair, S. Vauclair
White dwarfs are compact objects with atmospheres containing mainly light elements, hydrogen or helium. Because of their surface high gravitational field, heavy elements diffuse do…
Whole Earth Telescope Observations of the subdwarf B star KPD 1930+2752: A rich, short period pulsator in a close binary
M. D. Reed, S. L. Harms, S. Poindexter +58
KPD 1930+2752 is a short-period pulsating subdwarf B (sdB) star. It is also an ellipsoidal variable with a known binary period just over two hours. The companion is most likely a w…
Thermohaline Instabilities Induced by Heavy Element Accretion onto White Dwarfs: Consequences on the Derived Accretion Rates
M. Deal, S. Vauclair, G. Vauclair
Heavy elements are observed in the atmospheres of many DA and DB white dwarfs, and their presence is attributed to the accretion of matter coming from debris disks. Several authors…
Asteroseismological constraints on the coolest GW Vir variable star (PG 1159-type)PG 0122+200
A. H. Córsico, M. M. Miller Bertolami, L. G. Althaus +2
We present an asteroseismological study on PG 0122+200, the coolest known pulsating PG1159 (GW Vir) star. Our results are based on an augmented set of the full PG1159 evolutionary…