NOAO >   Observing Info >   Approved Programs >   2010B-0462

Small NOAO Logo

Proposal Information for 2010B-0462


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



NOAO >   Observing Info >   Approved Programs >   2010B-0462

noaoprop-help@noao.edu

Small NOAO Logo