August 11-15, 2014


Do the constants of nature couple to strong gravitational fields?

Simon Preval (University of Leicester)

Martin Barstow (University of Leicester), Jay Holberg (University of Arizona), John Barrow (University of Cambridge), Julian Berengut (University of New South Wales), John Webb (University of New South Wales), Darren Dougan (University of New South Wales), Jiting Hu (University of New South Wales)

Recently, white dwarf stars have found a new use in the fundamental physics community. Predicted in many Grand Unified Theories and Theories of Everything, the fundamental constants such as the fine structure constant (alpha) are thought to vary in some way. A study by Berengut et al. (2013) used the Fe/Ni V line measurements made by Preval et al. (2013) from the hot DA white dwarf G191-B2B, in an attempt to detect any variation in alpha. It was found that the Fe V lines indicated a decreasing alpha, whereas the Ni V lines indicated an increasing alpha. Possible explanations for this could be misidentification of the lines, inaccurate atomic data, or wavelength dependent distortion in the spectrum. We examine the first two cases by using a high S/N reference spectrum from the hot sdO BD+28D4211 to calibrate the Fe/Ni V atomic data. With this new data, we re-evaluate the work of Berengut et al. (2013) to derive a new constraint on the variation of alpha in a gravitational field.

Mode of presentation: poster