NOAO >   Observing Info >   Approved Programs >   2001B-0246

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Proposal Information for 2001B-0246


PI: Jay Holberg, University of Arizona, holberg@argus.lpl.arizona.edu
Address: 1040 E. Fourth Street, Tucson, AZ 85721, USA

CoI: Martin Barstow, University of Leicester
CoI: Matthew Burleigh, University of Leicester
CoI: Ivan Hubeny, Goddard Space Flight Center

Title: Metal Abundances and the Temperature Scale for Hot H-rich White Dwarfs

Abstract: We have developed the theoretical framework for a completely new way to estimate the trace levels of heavy elements in the atmospheres of hot DA white dwarfs. At present, the only way to establish heavy element abundances is from space at UV or EUV wavelengths. Even though undetected (until now) in the optical, the presence of heavy elements is known to significancy bias, effective temperature estimates obtained from the fitting of Balmer profiles. We seek to observationally verify our technique by high dispersion, high S/N observations of the non-LTE cores of the H(alpha) lines of a sample of hot DA white dwarfs, which have known heavy element abundances. If successful, our technique will allow critical estimates of heavy element abundance to be made from the optical alone and thereby greatly improve our knowledge of the temperature scale and hence the evolution of the DA stars.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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