  In the course of our search for double degenerate binaries as potential
progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT
(ESO SN Ia Progenitor surveY - SPY) we discovered that the sdB star HE
1047-0436 is radial velocity variable. The orbital period of 1.213253d, a
semi-amplitude of 94km/s, and a minimum mass of the invisible companion of
0.44Msol are derived from the analysis of the radial velocity curve. We use an
upper limit on the projected rotational velocity of the sdB star to constrain
the system inclination and the companion mass to M>0.71Msol, bringing the total
mass of the system closer to the Chandrasekhar limit. However, the system will
merge due to loss of angular momentum via gravitational wave radiation only
after several Hubble times. Atmospheric parameters and metal abundances are
also derived. The resulting values are typical for sdB stars.
