2015MNRAS.450.1237S

Recently we published an accurate analysis of molecular hydrogen absorption in the photospheres of the white dwarf stars GD133 and GD29-38, previously observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. Constraints were derived on a possible dependence of the proton-electron mass ratio on gravitational fields that are 10 000 times stronger than at the Earth's surface. Here we present further details of that study, in particular a re-evaluation of the spectrum of the B^1Σ_u^+ - X^1Σ_g^+ (v^′,v^′′) Lyman bands relevant for the prevailing temperatures (12 000-14 000 K) of the photospheres. The emphasis is on the calculation of so-called Ki-coefficients, that represent the sensitivity of each individual line to a possible change in the proton-electron mass ratio. Such calculations were performed by semi-empirical methods and by ab initio methods providing accurate and consistent values. A full listing is provided for the molecular physics data on the Lyman bands (wavelengths λi, line oscillator strengths fi, radiative damping rates Γi, and sensitivity coefficients Ki) as required for the analyses of H2-spectra in hot dwarf stars. A similar listing of the molecular physics parameters for the C^1Π_ u - X^1Σ_g^+ (v^′,v^′′) Werner bands is provided for future use in the analysis of white dwarf spectra.