“The difference of more than 40 degrees between the orbital axis and the black hole spin was completely unexpected. The results published in the Science magazine open interesting prospects towards studies of black hole formation and evolution of such systems, as such extreme misalignment is hard to get in many black hole formation and binary evolution scenarios. This was measured using polarimetric techniques,” says Juri Poutanen. “To determine the 3D orientation of the orbit, one additionally needs to know the position angle of the system on the sky, meaning how the system is turned with respect to the direction to the North on the sky. In this way, the researchers were able to measure the orbit inclination using spectroscopic techniques, and it happened to nearly coincide with the inclination of the ejections. As the amount of gas falling from the companion star to the black hole later began to decrease, the system dimmed, and much of the light in the system came from the companion star.

We see bright optical and X-ray radiation as the last sigh of the infalling material, and also radio emission from the relativistic jets expelled from the system,” says Juri Poutanen, Professor of Astronomy at the University of Turku and the lead author of the publication.īy following these jets, the researchers were able to determine the direction of the axis of rotation of the black hole very accurately. Now we see the black hole dragging matter from the nearby, lighter companion star orbiting around it. The black holes in these systems were formed as a result of a cosmic cataclysm – the collapse of a massive star. “The expectation of alignment, to a large degree, does not hold for the bizarre objects such as black hole X-ray binaries. The inclination of the Sun rotation axis with respect to orbital axis of the Earth is only seven degrees. This is true also for our solar system: the planets orbit around the Sun in a plane, which roughly coincides with the equatorial plane of the Sun. Often for the space systems with smaller objects orbiting around the central massive body, the own rotation axis of this body is to a high degree aligned with the rotation axis of its satellites. A narrow jet is directed along the black hole spin axis, which is strongly misaligned from the rotation axis of the orbit.

Artist impression of the X-ray binary system MAXI J1820+070 containing a black hole (small black dot at the center of the gaseous disk) and a companion star.

Death spiral black on side completely