A seismic approach to testing different formation channels of subdwarf B stars (2008)
Hu, Haili, Aerts, C., Nelemans, G., Kawaler, S. D., Miglio, A., ...
There are many unknowns in the formation of subdwarf B stars. Different formation channels are considered to be possible and to lead to a variety of helium-burning subdwarfs. All seismic models to...
Metcalfe, T. S., O'Donoghue, D., Winget, D. E., Kilkenny, D., Van Wyk, F., ...
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 observations (135h) were...
The pulsation modes of the pre-white dwarf PG 1159-035 (2008)
Costa, J. E. S., Kepler, S. O., Winget, D. E., O'Brien, M. S., Kawaler, S. D., Costa, A. F. M., ...
Context. PG 1159-035, a pre-white dwarf with T_(eff) ≃ 140 000 K, is the prototype of both two classes: the PG 1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-035...
The pulsation modes of the pre-white dwarf PG 1159-035 (2007)
Costa, J. E. S., Kepler, S. O., Winget, D. E., O'Brien, M. S., Kawaler, S. D., Costa, A. F. M., ...
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 1159-035 photometric data...
Whole Earth Telescope observations of the pulsating subdwarf B star PG 0014+067 (2006)
Vuckovic, M., Kawaler, S. D., Collaboration, For The WET
PG 0014+067 is one of the most promising pulsating subdwarf B stars for seismic analysis, as it has a rich pulsation spectrum. The richness of its pulsations, however, poses a fundamental challenge...
Bedding, T. R., Kiss, L. L., Kjeldsen, H., Brewer, B. J., Dind, Z. E., Kawaler, S. D., ...
We analyse visual observations of the pulsations of the red giant variable L2 Pup. The data cover 77 years between 1927 and 2005, thus providing an extensive empirical base for characterizing...
Winget, D. E., Sullivan, D. J., Metcalfe, T. S., Kawaler, S. D., Montgomery, M. H.
We demonstrate that plasmon neutrinos are the dominant form of energy loss in model white dwarf stars down to T_eff ~ 25,000 K, depending on the stellar mass. The lower end of this range overlaps the...
Since pulsating subdwarf B (sdBV or EC14026) stars were first discovered (Kilkenny et al, 1997), observational efforts have tried to realize their potential for constraining the interior physics of...
The evolution of a hot subdwarf: observations of the pulsating subdwarf B star Feige~48 (2003)
Since pulsating subdwarf B (sdBV or EC14026) stars were first discovered (Kilkenny et al, 1997), observational efforts have tried to realize their potential for constraining the interior physics of...
Probing the core and envelope structure of DBV white dwarfs (2003)
Metcalfe, T. S., Montgomery, M. H., Kawaler, S. D.
We investigate the global pulsation properties of DBV white dwarf models that include both the double-layered envelope structure expected from time-dependent diffusion calculations, as well as a...
Discover of the "missing" mode in HR 1217 by the Whole Earth Telescope (2001)
HR 1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of nonradial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating...
Evolutionary Timescale of the DAV G117-B15A: The Most Stable Optical Clock Known (2000)
Kepler, S. O., Mukadam, Anjum, Winget, D. E., Nather, R. E., Metcalfe, T. S., Reed, M. D., ...
We observe G117-B15A, the most precise optical clock known, to measure the rate of change of the main pulsation period of this blue-edge DAV white dwarf. Even though the obtained value is only within...
Understanding the Cool DA White Dwarf, G29-38 (1997)
Kleinman, S. J., Nather, R. E., Winget, D. E., Clemens, J. C., Bradley, P. A., Kanaan, A., ...
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...