H-2 Lyman and Werner band lines and their sensitivity for a variation of the proton-electron mass ratio in the gravitational potential of white dwarfs

E.J. Salumbides, J. Bagdonaite, H. Abgrall, E. Roueff, W.M.G. Ubachs

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

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 B1+<inf>u</inf> - X1+<inf>g</inf> (v1, vn) Lyman bands relevant for the prevailing temperatures (12 000-14 000 K) of the photospheres. The emphasis is on the calculation of so-called K<inf>i</inf>-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 λ<inf>i</inf>, line oscillator strengths f<inf>i</inf>, radiative damping rates λ<inf>i</inf>, and sensitivity coefficients K<inf>i</inf>) as required for the analyses of H<inf>2</inf>-spectra in hot dwarf stars. A similar listing of the molecular physics parameters for the C1π<inf>u</inf> - X1∑+<inf>g</inf> (v1, vn) Werner bands is provided for future use in the analysis of white dwarf spectra.
Original languageEnglish
Pages (from-to)1237-1245
JournalMonthly Notices of the Royal Astronomical Society
Volume450
Issue number2
DOIs
Publication statusPublished - 2015

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