Polar jet flow , or jet , is a phenomenon often observed in space when flows of matter are ejected from a compact object along its axis of rotation . The reason is usually dynamic interactions within the accretion disk . When matter is emitted at a speed close to the speed of light , such flows are called relativistic jets .
Disks that exist around many stars can generate polar jets, but those that exist near black holes are the fastest and most active. This is explained by the fact that the jet velocity is approximately the same as the escape velocity from the central object, so that the velocity of polar currents near black holes is close to the speed of light, while the velocity of currents near protostars is much lower. The largest polar flows can be seen in active galaxies , such as quasars .
Other objects in which polar currents are often observed are cataclysmic variable stars, X-ray binary systems, and T Taurus stars . Herbig-Aro objects are formed by the interaction of polar jet streams from young stars with the surrounding interstellar medium . A variety of polar currents — bipolar gas flows — can also be associated with protostars (stars at an early stage of formation) or with evolved post-AGB stars (often in the form of a bipolar nebula ).
Education Mechanism
Despite the fact that for physicists the formation and existence of polar flows is still a mystery, two sources for maintaining their existence are most often called: a central object (for example, a black hole ) and an accretion disk . The exact mechanism for the formation of jets from an accretion disk is not clear, but it is assumed that it consists in the formation of complex magnetic fields by the disks, which cause the jets to come together. In part, this mechanism may resemble the hydrodynamics of a Laval nozzle .
The best way to understand this mechanism is to determine the composition of the jets in a place where they can be directly seen. For example, a plasma from a jet near a black hole will have a different composition depending on whether it comes from an accretion disk ( electron – ion ) or from a black hole (electron – positron ). Plasma also has a different emission spectrum, such as x-ray or radio waves .
Research from NASA satellites made it possible to detect and track the routes of sufficiently independent and stable whirlpools in the Atlantic Ocean, which prompted scientists to compare mathematical models of such “ eddies ” [1] [2] , oceanic vortices and a black hole vortex. A thorough resemblance was discovered. On the other hand, oceanographic expeditions have been organized quite regularly in the Atlantic for a long time, in one of which field measurements and observations appeared, as well as a peculiar theory of hurricane formation . A common was the release of a kind of jet by the oceanic whirlpools. This made it possible to apply for black holes the general property of vortices - the formation of a rod rarefaction cavity with simultaneous pressure and deformation of the surface of the medium in the vortex funnel, paradoxically coordinated in the work of the yin-yang, which at the limit of the system of forces and properties of the medium leads to periodic collapse of "vacuum" ( cavitation) cavities with jets ejection. These and other materials and hypotheses are collected on the Relativistic Jet page.
Notes
- ↑ Oceanic whirlpools are thought to work in the same way as black holes . Mail Online (September 23, 2013). Date of treatment January 3, 2019.
- ↑ Angelika Jacobs, ETH Zurich. Ocean Eddies Are Mathematically Equivalent to Black Holes ( unspecified ) ? . SciTechDaily (September 24, 2013). Date of treatment January 3, 2019.