Orbital Period Increase in ES Ceti

TL;DR

This study presents evidence that gravitational radiation drives the evolution of the helium binary ES Ceti, showing a rapid increase in its orbital period consistent with theoretical predictions for old cataclysmic variables.

Contribution

First dynamical evidence linking gravitational radiation to the orbital evolution of AM Canum Venaticorum stars based on long-term eclipse timing observations.

Findings

Orbital period of ES Ceti is increasing rapidly.

The period change aligns with gravitational radiation-driven mass transfer.

Provides observational support for theoretical models of AM CVn star evolution.

Abstract

We report a long-term study of the eclipse times in the 10-minute helium binary ES Ceti. The binary period increases rapidly, with P/P-dot = 6.2x10^6 yr. This is consistent with the assumption that gravitational radiation (GR) drives the mass transfer, and appears to be the first dynamical evidence that GR is indeed the driver of evolution in this class of very old cataclysmic variables -- the AM Canum Venaticorum stars.