1991/09/01 by S. O. Kepler, D. E. Winget, R. E. Nather +34 · 3 citations
Physics and Astronomy · Engineering · #Stellar, planetary, and galactic studies #Astronomy and Astrophysical Research #Astronomical Observations and Instrumentation
paper · pdf · doi:10.1086/186138
We have detected the time rate of change for the main pulsation period of the 13,000 K DA white dwarf G117-B15A, using the Whole Earth Telescope (WET). The observed rate of period change, P = (12.0 ± 3.5) x 10- 15 s s - ', is somewhat larger than the published theoretical calculations of the rate of period change due to cooling, based on carbon core white dwarf models. We discuss other effects that could contribute to the observed rate of period change.