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 sigma, P&d2;=&parl0;2.3+/-1.4&parr0;x10-15 s s-1, it is already constraining the evolutionary timescale of this cooling white dwarf star.
Kepler
SO
Mukadam
A
Winget
DE
Nather
RE
Metcalfe
TS
Reed
MD
Kawaler
SD
Bradley
PA