SIMBAD references

The quasar OJ 287 shows variability behavior in almost any scale, from tens of minutes to years. The most clear instances are double-peaked outbursts at about 12 yr intervals; these have been observed for over 100 yr. The light curve has led to numerous models. We study the double-penetration binary black hole model of Lehto & Valtonen. We have carried out an extensive search over the parameter space for combinations of parameters that give flare beginning times that fit the selected observations. The search gives limits for parameters of the binary orbit and the accretion disk and correlations between parameters and flare times. We discuss some allegations and pros and cons of the model. We have also studied other delay options.