1994A&A...290..428H

We present new near-infrared (NIR) broadband photometry of LSI+61 303 centered around two predicted radio maxima and minima in order to search for NIR variability that may or may not be correlated with the periodic radio variations in this object. To improve the significance of any upper limit on variability, we adopted a differential measurement technique to minimize the photometric uncertainties. We have combined our data with those in the literature and calculated the dereddened NIR excess for the combined data set. Although the excess varies stochastically by more than a factor of two, a search for periodicities in the NIR excess with the phase dispersion minimization method gives no statistically significant periodic variation. Moreover, we find no hour-timescale fluctuations in the NIR of the sort detected at optical wavebands. The J-H and H-K colors of the dereddened NIR excess are blue, and roughly consistent with those expected from isothermal circumstellar disks or 4000-5000K blackbodies.