NOAO > Observing Info > Approved Programs > 2010B-0462
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NOAO > Observing Info > Approved Programs > 2010B-0462 |
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PI: S.O. Kepler, Universidade Federal do Rio Grande do Sul, kepler@if.ufrgs.br
Address: Instituto de Fisica, 91501-970 Porto Alegre, RS, Brazil
CoI: Alejandro Corsico, Facultad de Ciencias Astronomicas y Geofisicas
CoI: Leandro Althaus, Facultad de Ciencias Astronomicas y Geofisicas
CoI: Don Winget, University of Texas
CoI: Scot Kleinman, Gemini Observatory
CoI: Atsuko Nitta, Gemini Observatory
CoI: Barbara Castanheira, University of Texas
CoI: Detlev Koester, Universitat Kiel
Title: Spectroscopy of magnetic white dwarf stars
Abstract:
We have visually examined the spectra of all color selected white dwarfs in
the SDSS DR7 and found that around one thousand white dwarfs show strong
evidence of Zeeman splittings, caused by magnetic fields of the order of 1 to
30 MG. Stronger fields affect the position of the lines so much that we did
not easily classify the stars as DAs or DBs initially. Our work suggests that
the number of magnetic white dwarf stars have been underestimated by a factor
of 5 to 10. We propose to obtain S/N>70 spectra for ten of these newly
discovered magnetic white dwarf stars to test if the Zeeman splittings are
real and to measure the field values. Magnetic fields of the order of mega
gauss affect the line profiles so strongly that the lines cannot be used to
determine surface gravity, so we had to exclude those stars from our mean
mass estimates.
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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NOAO > Observing Info > Approved Programs > 2010B-0462 |
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