OJ 287

OJ 287 is a binary black hole system located approximately 3.5 billion light-years from Earth in the constellation Cancer. It is a blazar, meaning its jet of relativistic particles is pointed directly toward Earth, making it a powerful source of electromagnetic radiation across the spectrum, from radio waves to gamma rays.

The system consists of a supermassive black hole, estimated to be around 18 billion times the mass of the Sun, and a smaller black hole, estimated to be around 150 million times the mass of the Sun, orbiting it in an eccentric path. This orbit brings the smaller black hole crashing through the accretion disk surrounding the larger black hole approximately every 12 years.

These collisions are predicted to cause dramatic flares of light as the smaller black hole punches through the accretion disk, heating the surrounding gas to extreme temperatures. These flares have been observed for over a century, and the timing of the flares provides valuable information about the orbital parameters and masses of the black holes. However, the flares do not occur precisely every 12 years; they vary by as much as 1-2 years due to the precession of the smaller black hole's orbit and the complexity of the accretion disk.

Research on OJ 287 continues to focus on refining models of the system's dynamics, using observed flare timings to test general relativity in the strong-field regime, and understanding the processes that generate the powerful jets of particles emitted from the blazar. Accurate predictions of future flares are a key goal of ongoing research.