Evolutionary Timescale of the Pulsating White Dwarf G117-B15A: The Most Stable Optical Clock Known

Area of Science:

• * Astrophysics
• * Stellar Evolution
• * Observational Astronomy

Background:

• * White dwarf stars are the remnants of low-to-medium mass stars after they have exhausted their nuclear fuel.
• * DAV white dwarfs are a subclass characterized by their hydrogen-rich atmospheres and pulsations.
• * Precise measurement of white dwarf cooling is crucial for understanding stellar evolution and age dating.

Purpose of the Study:

• * To measure the rate of change of the main pulsation period of the blue-edge DAV white dwarf G117-B15A.
• * To utilize the G117-B15A, the most precise optical clock, for astrophysical measurements.
• * To constrain the evolutionary timescale of G117-B15A.

Main Methods:

• * Employed the G117-B15A optical clock for high-precision timing observations.
• * Monitored the pulsation period of the G117-B15A white dwarf over a specific observation period.
• * Analyzed timing data to determine the rate of change of the pulsation period.

Main Results:

• * Measured the rate of change of the main pulsation period of G117-B15A as (2.3 ± 1.4) x 10^-15 s s^-1.
• * The obtained measurement, while within 1 sigma uncertainty, is significant for constraining theoretical models.
• * This represents a novel application of an optical clock for stellar astrophysics.

Conclusions:

• * The measurement provides initial constraints on the evolutionary timescale of the G117-B15A white dwarf.
• * Future observations with enhanced precision could further refine these constraints.
• * This study demonstrates the potential of optical clocks in advancing stellar evolution research.