Photometric and H$\alpha$ observations of LSI+61303: detection of a   $\sim$26 day V and JHK band modulation
  We present new optical and infrared photometric observations and high resolution H$\alpha$ spectra of the periodic radio star \lsi. The optical photometric data set covers the time interval 1985-1993 and amounts to about a hundred nights. A period of $\sim$26 days is found in the V band. The infrared data also present evidence for a similar periodicity, but with higher amplitude of variation (0\rmag 2). The spectroscopic observations include 16 intermediate and high dispersion spectra of \lsi\ collected between January 1989 and February 1993. The H$\alpha$ emission line profile and its variations are analyzed. Several emission line parameters -- among them the H$\alpha$ EW and the width of the H$\alpha$ red hump -- change strongly at or close to radio maximum, and may exhibit periodic variability. We also observe a significant change in the peak separation. The H$\alpha$ profile of \lsi\ does not seem peculiar for a Be star. However, several of the observed variations of the H$\alpha$ profile can probably be associated with the presence of the compact, secondary star. 
J. M. Paredes, P. Marziani, J. Marti, J. Fabregat, M. J. Coe, C.   Everall, F. Figueras, C. Jordi, A. J. Norton, T. Prince, ...