Evolutionary timescale of the pulsating white dwarf G117-B15A: The most stable optical clock known
We observe G117-B15A, the most precise optical clock known, to measure the rate of change of the main pulsation period of this blue-edge DAV white dwarf. Even though the obtained value is only within 1 σ, P = (2.3 ± 1.4) × 10-15 s s-1, it is already constraining the evolutionary timescale of this cooling white dwarf star.
Stars: evolution, Stars: individual (G117-B15A), Stars: oscillations
Kepler, Souza Oliveira, Anjum Mukadam, Donald Earl Winget, R. Edward Nather, Travis S. Metcalfe, M. D. Reed, Steven D. Kawaler, and Paul A. Bradley. "Evolutionary timescale of the pulsating white dwarf G117-B15A: the most stable optical clock known." The Astrophysical Journal Letters 534, no. 2 (2000): L185.