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Stellar jet


An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as an extended beam along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets become relativistic jets as they show effects from special relativity.

Formation and powering of astrophysical jets is not fully understood, but it is likely that they arise from dynamic interactions within accretion disks or from active processes associated with compact central objects such as black holes, neutron stars or pulsars. One possible explanation is that tangled magnetic fields aim two diametrically opposing beams away from the central source by angles only several degrees wide. (c.>1%.). According to another hypothesis, the jets are due to an effect in general relativity known as frame-dragging.

Most of the largest and most active jets are created by supermassive black holes (SMBH) in the centre of active galaxies such as quasars and radio galaxies or within galaxy clusters. Such jets can exceed millions of parsecs in length. Other astronomical objects that contain jets include cataclysmic variable stars, X-ray binaries and Gamma ray bursters (GRB). Others are associated with star forming regions including T Tauri stars and Herbig–Haro objects, which are caused by the interaction of jets with the interstellar medium. Bipolar outflows or jets may also be associated with protostars, or with evolved post-AGB stars, planetary nebulae and bipolar nebulae.


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