A tidal disruption event (TDE) is a
transient astronomical source produced when a
star
A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
passes so close to a
supermassive black hole
A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...
(SMBH) that it is pulled apart by the black hole's
tidal force
The tidal force or tide-generating force is the difference in gravitational attraction between different points in a gravitational field, causing bodies to be pulled unevenly and as a result are being stretched towards the attraction. It is the ...
.
The star undergoes
spaghettification
In astrophysics, spaghettification (sometimes referred to as the noodle effect) is the vertical stretching and horizontal compression of objects into long thin shapes (rather like spaghetti) in a very strong, non- homogeneous gravitational fi ...
, producing a
tidal stream of material that loops around the black hole. Some portion of the stellar material is captured into orbit, forming an
accretion disk
An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and ...
around the black hole, which emits
electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
. In a small fraction of TDEs, a
relativistic jet
An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as extended beams along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets becom ...
is also produced. As the material in the disk is gradually consumed by the black hole, the TDE fades over several months or years.
TDEs were predicted in the 1970s and first observed in the 1990s. Over a hundred have since been observed, with detections at optical, infrared, radio and X-ray wavelengths. Sometimes a star can survive the encounter with an SMBH, leaving a remnant; those events are termed partial TDEs.
History
TDEs were first theorized by
Jack G. Hills in 1975. A consequence of a star getting sufficiently close to a SMBH that the tidal forces between the star will overcome the star's
self-gravity. In 1988