title: Limits on the dependence of the fine-structure constant on gravitational potential from white-dwarf spectra.
abstract: We propose a new probe of the dependence of the fine-structure constant α on a strong gravitational field using metal lines in the spectra of white-dwarf stars. Comparison of laboratory spectra with far-UV astronomical spectra from the white-dwarf star G191-B2B recorded by the Hubble Space Telescope Imaging Spectrograph gives limits of Δα/α=(4.2±1.6)×10(-5) and (-6.1±5.8)×10(-5) from FeV and NiV spectra, respectively, at a dimensionless gravitational potential relative to Earth of Δφ≈5×10(-5). With better determinations of the laboratory wavelengths of the lines employed these results could be improved by up to 2 orders of magnitude.
authors.affiliation: School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: J C
authors.initials: JC
authors.lastname: Berengut
authors.forename: V V
authors.initials: VV
authors.lastname: Flambaum
authors.forename: A
authors.initials: A
authors.lastname: Ong
authors.forename: J K
authors.initials: JK
authors.lastname: Webb
authors.forename: John D
authors.initials: JD
authors.lastname: Barrow
authors.forename: M A
authors.initials: MA
authors.lastname: Barstow
authors.forename: S P
authors.initials: SP
authors.lastname: Preval
authors.forename: J B
authors.initials: JB
authors.lastname: Holberg