2004ApJ...601L..83W

By using the Adaptive Optics with a Laser for Astronomy system at the 3.6 m telescope of the Calar Alto Observatory, we detected a faint red star in the apparent vicinity of FU Ori, the prototype of the FUor outburst stars. Independent confirmation of the detection is obtained from archival Probing the Universe with Enhanced Optics/Canada-France-Hawaii Telescope images. The separation between the companion candidate and FU Ori is 0".50, and their brightness contrast is around 4 mag. We discuss the possible nature of the newly detected star based on near-infrared photometry and its proper motion relative to FU Ori. The photometric data are consistent with a nearby late-type main-sequence star, a background giant star, and a pre-main-sequence star. On the basis of the proper motion and the stellar surface density in the direction toward FU Ori, we argue that the probabilities of the first two options are very low.