We present ellipsoidal light-curve fits to the quiescent B , V , R and I\ / light curves of GRO J1655–40 ( Nova Scorpii 1994 ) .
The fits are based on a simple model consisting of a Roche-lobe filling secondary and an accretion disc around the black-hole primary .
Unlike previous studies , no assumptions are made about the interstellar extinction or the distance to the source ; instead these are determined self-consistently from the observed light curves .
In order to obtain tighter limits on the model parameters , we used the distance determination from the kinematics of the radio jet as an additional constraint .
We obtain a value for the extinction that is lower than was assumed previously ; this leads to lower masses for both the black hole and the secondary star of 5.4 \pm 0.3 M _ { \sun } and 1.45 \pm 0.35 M _ { \sun } , respectively .
The errors in the determination of the model parameters are dominated by systematic errors , in particular due to uncertainties in the modeling of the disk structure and uncertainties in the atmosphere model for the chemically anomalous secondary in the system .
A lower mass of the secondary naturally explains the transient nature of the system if it is either in a late case A or early case B mass-transfer phase .