Broad-band photometry of extreme helium stars.

The authors present UBVRIJHKL photometry of most known extreme helium stars and hydrogen-deficient binaries. The two stars which show pronounced infrared excesses, υ Sgr and LSS 4300, are both hydrogen-deficient binaries. A third star, LSS 1922, also appears to be a hydrogen-deficient binary, but it does not have a pronounced infrared excess. The other nine stars are apparently single, and none of them shows an infrared excess. It is concluded that some of the hydrogen-deficient binaries have circumstellar dust shells, but that single extreme helium stars do not.