Limits on the dependence of the fine-structure constant on gravitational potential from white-dwarf spectra

J. C. Berengut, V. V. Flambaum, A. Ong, J. K. Webb, John D. Barrow, M. A. Barstow, S. P. Preval, J. B. Holberg

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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 Δp≈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.

Original languageEnglish
Article number010801
Number of pages5
JournalPhysical Review Letters
Issue number1
Publication statusPublished - 3 Jul 2013


  • fine structure constants
  • gravitational potential
  • Hubble space telescopes
  • imaging spectograph
  • metal line
  • orders of magnitude
  • strong gravitational fields
  • gravitation
  • stars

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