Infrared spectroscopy of GX 1+4/V2116 Ophiuchi: Evidence for a fast red giant wind?

We present infrared spectroscopy of the low-mass X-ray binary GX 1+4/V2116 Ophiuchi. This symbiotic binary consists of a 2 minute accretion-powered pulsar and an M5 III red giant, A strong He I 1.083 mu m emission line with a pronounced P Cygni profile was observed. From the blue edge of this feature, we infer an outflow velocity of 250 +/- 50 km s(-1). This is an order of magnitude faster than a typical red giant wind, and we suggest that radiation from the accretion disk or the neutron star may contribute to the acceleration of the outflow. We infer a wind mass-loss rate of similar to 10(-6) M. yr(-1). Accretion from such a strong stellar wind provides a plausible alternative to Roche lobe overflow for supplying the accretion disk that powers the X-ray source. The H I Pa beta and He I 1.083 mu m emission lines show no evidence for the dramatic variability previously reported in some optical lines and no evidence for pulsations at the 2 minute pulsar period.