RX J1914.4+2456 is a candidate double-degenerate binary ( AM CVn ) with a putative 569 s orbital period .
If this identification is correct , then it has one of the shortest binary orbital periods known , and gravitational radiation should drive the orbital evolution and mass transfer if the binary is semi-detached .
Here we report the results of a coherent timing study of the archival ROSAT and ASCA data for RX J1914.4+2456 .
We performed a phase coherent timing analysis using all observations spanning an \approx 4.6 year period .
We demonstrate that all the data can be phase connected , and we present evidence that the 1.756 mHz orbital frequency is increasing at a rate of 8 \pm 3 \times 10 ^ { -18 } Hz s ^ { -1 } , consistent with the expected loss of angular momentum from the binary system via gravitational radiation .
In addition to providing evidence for the emission of gravitational waves , measurement of the orbital \dot { \nu } constrains models for the X-ray emission and the nature of the secondary .
If stable mass accretion drives the X-ray flux , then a positive \dot { \nu } is inconsistent with a degenerate donor .
A helium burning dwarf is compatible if indeed such systems can have periods as short as that of RX J1914.4+2456 , an open theoretical question .
Our measurement of a positive \dot { \nu } is consistent with the unipolar induction model of Wu et al .
which does not require accretion to drive the X-ray flux .
We discuss how future timing measurements of RX J1914.4+2456 ( and systems like it ) with for example , Chandra and XMM-Newton , can provide a unique probe of the interaction between mass loss and gravitational radiation .
We also discuss the importance of such measurements in the context of gravitational wave detection from space , such as is expected in the future with the LISA mission .