Optical spectroscopy of the 2005 outburst of the X-ray transient XTE J1118+480

We present time-resolved spectroscopy from the January 2005 outburst of the X-ray nova XTE J1118+480. X-ray observations show this outburst to be about half as bright as the previous outburst in 2000. This suggests that the accretion rate was lower than that in the 2000 outburst. Our spectroscopic analysis shows that the emission from the Hα line occurs at a higher velocity in the recent outburst compared with the 2000 outburst, more consistent with quiescence/near-quiescence values. This is surprising, considering the ∼5 magnitude brightening of the accretion disk relative to its quiescent state.