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Paper: Time Series Spectroscopy: Mode Identification of White Dwarf Stars
Volume: 352, New Horizons in Astronomy: Frank N. Bash Symposium 2005
Page: 289
Authors: Thompson, S.E.
Abstract: I show the preliminary results of optical time series spectroscopy taken of the pulsating white dwarf star G 29-38. With these spectra, I identify the spherical degree of the star's largest pulsation modes; a necessary quantity to accurately probe the stellar interior with asteroseismology. Because limb-darkening is wavelength dependent, the observed line-shape variations of the broad Hydrogen Balmer lines depend on the spherical degree of the mode. Thompson et al. (2004) discovered that constrained fitting of the spectral lines enables mode identification where direct measurements of amplitude from the spectra failed. I use the free parameters from fitting the spectra to quantify the variations in the line shape. To identify the spherical degree, the periodic change in the parameter values are compared to fits of spectra created from model atmospheres of white dwarf stars. Simulations of noisy model spectra demonstrate that the scatter around the model limits identification to the the largest amplitude modes.br>
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