The ellipsoidal shape of the M giant in T Coronae Borealis.

We present IR observations that give evidence for a pronounced ellipsoidal shape of the M3 giant in the recurrent nova T Coronae Borealis. Our observations, which span 1340 days or 5.8 orbital periods, do not show any of the shorter period scale variabilities sometimes encountered in the optical. A slight revision of the orbital period from 227.53 to 227.59 days seems supported by our IR photometry.