Whole Earth Telescope observations of BPM 37093: A seismological test of crystallization theory in white dwarfs

@article{Kanaan2005WholeET,
  title={Whole Earth Telescope observations of BPM 37093: A seismological test of crystallization theory in white dwarfs},
  author={A. Kanaan and Atsuko Nitta and Don E. Winget and S. O. Kepler and Michael H. Montgomery and Travis S. Metcalfe and et al.},
  journal={Astronomy and Astrophysics},
  year={2005},
  volume={432},
  pages={219-224}
}
BPM 37093 is the only hydrogen-atmosphere white dwarf currently known which has sufficient mass (~1.1 $M_\odot$) to theoretically crystallize while still inside the ZZ Ceti instability strip ($T_{\rm eff}\sim12\,000$ K). As a consequence, this star represents our first opportunity to test crystallization theory directly. If the core is substantially crystallized, then the inner boundary for each pulsation mode will be located at the top of the solid core rather than at the center of the star… 

Figures and Tables from this paper

Asteroseismological analysis of the ultra-massive ZZ Ceti stars BPM 37093, GD 518, and SDSS J0840+5222
Context. Ultra-massive (≳1 M⊙) hydrogen-rich (DA) white dwarfs are expected to have a substantial portion of their cores in a crystalline state at the effective temperatures characterising the ZZ
DISCOVERY OF AN ULTRAMASSIVE PULSATING WHITE DWARF
We announce the discovery of the most massive pulsating hydrogen-atmosphere white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12, 030 ±
ASTEROSEISMOLOGICAL STUDY OF MASSIVE ZZ CETI STARS WITH FULLY EVOLUTIONARY MODELS
We present the first asteroseismological study for 42 massive ZZ Ceti stars based on a large set of fully evolutionary carbon–oxygen core DA white dwarf models characterized by a detailed and
Four new massive pulsating white dwarfs including an ultramassive DAV
We report the discovery of four massive ($M > 0.8\,M_\odot$) ZZ Ceti white dwarfs, including an ultramassive $1.16\,M_\odot$ star. We obtained ground based, time-series photometry for thirteen white
Discovery of five new massive pulsating white dwarf stars
Using the SOuthern Astrophysical Research telescope (SOAR) Optical Imager at the SOAR 4.1 m telescope, we report on the discovery of five new massive pulsating white dwarf stars. Our results
Pulsating white dwarfs: new insights
Stars are extremely important astronomical objects that constitute the pillars on which the Universe is built, and as such, their study has gained increasing interest over the years. White dwarf
The search for ZZ Ceti stars in the original Kepler mission
We report the discovery of 42 white dwarfs in the original Kepler mission field, including nine new confirmed pulsating hydrogen-atmosphere white dwarfs (ZZ Ceti stars). Guided by the Kepler-Isaac
NEW CHEMICAL PROFILES FOR THE ASTEROSEISMOLOGY OF ZZ CETI STARS
We compute new chemical profiles for the core and envelope of white dwarfs appropriate for pulsational studies of ZZ Ceti stars. These profiles are extracted from the complete evolution of progenitor
The ZZ Ceti star G 185-32: new insight from asteroseismology
One of the brightest pulsating DA white dwarfs (ZZ Ceti stars), G 185-32, shows 19 periods in its power spectrum, from 71 s to 651 s. Its short periods are among the shortest ones observed in a ZZ
The gravitational wave radiation of pulsating white dwarfs
We compute the emission of gravitational radiation from pulsating white dwarfs. This is done for a standard 0.6M⊙ white dwarf with a liquid CO core and a H‐rich envelope, for a massive DA white dwarf
...
...

References

SHOWING 1-10 OF 30 REFERENCES
BPM 37093: The Way to the Interior of Crystallized Stars
BPM 37093 is a ZZ Ceti type star of the mass ~ 1.1 MQ. Its temperature 11 000 K) and high mass imply that it should be crystallized throughout most of its core, the exact fraction depending on the
The MOST Asteroseismology Mission: Ultraprecise Photometry from Space
The Microvariablity and Oscillations of Stars (MOST) mission is a low‐cost microsatellite designed to detect low‐degree acoustic oscillations (periods of minutes) with micromagnitude precision in
The Consequences of Assuming m=0 for Global Model-Fitting
Abstract A recent re-analysis of Whole Earth Telescope observations of GD 358 obtained in 1990 suggest that asteroseismology of additional DBV white dwarfs can lead to independent constraints on the
Constraining the Evolution of ZZ Ceti
We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf) ZZ Ceti, also called R548. On the basis of observations that span 31 years, we
Mode identification from time-resolved spectroscopy of the pulsating white dwarf G29-38
We have used time-resolved spectroscopy to measure the colour dependence of pulsation amplitudes in the DAV white dwarf G29-38. Model atmospheres predict that mode amplitudes should change with
On the Purity of the ZZ Ceti Instability Strip: Discovery of More Pulsating DA White Dwarfs on the Basis of Optical Spectroscopy
We report the discovery of two new ZZ Ceti pulsators, LP 133-144 and HE 1258+0123, selected on the basis of model atmosphere fits to optical spectroscopic data. The atmospheric parameters for LP
Understanding the Cool DA White Dwarf Pulsator, G29–38
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 internal structures and
BPM 37093: preliminary results from XCOV 16 and XCOV 17
BPM 37093 is a 1.1 M 0 ZZ Ceti star. This star's temperature 11 000 K) and high mass 1.1M©) imply that it should be crystallized throughout most of its core, the exact fraction depending on its core
Constraints on the age and evolution of the Galaxy from the white dwarf luminosity function
The white dwarf disk luminosity function is explored using observational results of Liebert et al. (1988, 1989) as a template for comparison, and the cooling curves of Wood (1990, 1991) as the input
New evolutionary models for massive ZZ Ceti stars. I. First results for their pulsational properties
We present new and improved evolutionary calculations for carbon-oxygen white dwarf (WD) stars appropriate for the study of massive ZZ Ceti stars. To this end, we follow the complete evolution of
...
...