Context : V617 Sgr is a V Sagittae star – a group of binaries thought to be the galactic counterparts of the Compact Binary Supersoft X-ray Sources – CBSS .

Aims : To check this hypothesis , we measured the time derivative of its orbital period .

Methods : Observed timings of eclipse minima spanning over 30,000 orbital cycles are presented .

Results : We found that the orbital period evolves quite rapidly : P / \dot { P } = 1.1 \times 10 ^ { 6 } years .
This is consistent with the idea that V617 Sgr is a wind driven accretion supersoft source .
As the binary system evolves with a time-scale of about one million years , which is extremely short for a low mass evolved binary , it is likely that the system will soon end either by having its secondary completely evaporated or by the primary exploding as a supernova of type Ia .

Conclusions :