UBC Undergraduate Research

HIRES Spectroscopy of Magnetic White Dwarfs McAnerin, Mark


The atmospheres of magnetic white dwarfs behave as theoretical analogues to neutron stars. The magnetic fields strengths and effective temperatures of the white dwarfs with the strongest magnetic fields are both two to three orders of magnitude below neutron stars. So the expectation is that their atmospheres and stellar enevelopes will be as difficult to model as neutron stars due to the high degree of anisotropy in the thermal conduction through their atmospheres and envelopes. The construction of spectra and analyzing their absorption features with data taken with the HIRES instrument on Keck-I, could better constrain the models for all magnetic stellar atmospheres. Using the response transfer method of reducing echelle spectra we have created complete relative flux spectra of several magnetic white dwarf targets. Our reference in the reduction is Van Maanen 2, which behaves as a good blackbody and is devoid of spectral features above 4000°A. Errors between orders due to the limitations of our method have prevented assembly of complete continuous spectra, but spectral data seems to indicate that there ranges of spectra up to several hundred angstroms wide with low systematic error, allowing analysis of the large spectral features of magnetic white dwarfs.

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