Observations of the unusual counterpart to the X-ray pulsar AX J0051-733
  We report optical and IR observations of the ASCA X-ray pulsar system AX J0051-733. The relationship between the X-ray source and possible optical counterparts is discussed. Long term optical data from over 7 years are presented which reveal both a 1.4d modulation and an unusually rapid change in this possible binary period. Various models are discussed. 
M.J. Coe (Southampton Univ), N.J. Haigh (Southampton Univ), S.G.T.   Laycock (Southampton Univ), I. Negueruela (Obs de Stras...