A tidal disruption event (also known as a tidal disruption flare) is an astronomical phenomenon that occurs when a star approaches sufficiently close to a supermassive black hole that it is pulled apart by the black hole's tidal force, experiencing spaghettification. A portion of the star's mass can be captured into an accretion disk around the black hole, resulting in a temporary flare of electromagnetic radiation as matter in the disk is consumed by the black hole.
According to early papers (see History section), tidal disruption events should be an inevitable consequence of massive black holes activity hidden in galaxy nuclei, whereas later theorists concluded that the resulting explosion or flare of radiation from the accretion of the stellar debris could be a unique signpost for the presence of a dormant black hole in the center of a normal galaxy.
It was in 1971 that for the first time the theorist John A. Wheeler suggested that the breakup of a star in the ergosphere of a rotating black hole could induce acceleration of the released gas to relativistic speeds by the so-called "tube of toothpaste effect". Wheeler succeeded in applying the relativistic generalization of the classical Newtonian tidal disruption problem to the neighborhood of a Schwarzschild or a Kerr black hole (without axial rotation or in rotation, cf. Fishbone (1973) and Mashhoon (1975, 1977)). But these early works restricted their attention to incompressible star models and/or to stars penetrating slightly into the Roche radius, thus undergoing only tides of small amplitudes or, at best, only quiescent disruption phenomena (aka the future TDE).
In 1976 in the "MNRAS" astronomers Juhan Frank and Martin F. Rees of the Cambridge Institute of Astronomy evoked for the first time "the effect of massive black holes on stellar systems", defining a critical radius under which stars are disturbed and literally sucked up by the black hole, suggesting that it is possible to observe these events in certain galaxies. But at the time, the English researchers did not propose any precise model or simulation.
This speculative prediction and this lack of theoretical tools aroused the curiosity of Jean-Pierre Luminet and Brandon Carter of the Paris Observatory in the early 1980s who invented the concept of TDE. Their first works were published in 1982 in the journal Nature and in 1983 in the Astronomy & Astrophysics. The authors had managed to describe the tidal disturbances in the heart of AGNs based on the "stellar pancake outbreak" model to use Luminet's expression, a model describing the tide field generated by a "big black hole" - let's say supermassive - and the effect they called the "pancake detonation" to qualify the radiation outbreak resulting from these disturbances.
Then in 1986, Luminet and Carter published in the journal Astrophysical Journal Supplement an important article of 29 pages in which they analyzed all the cases of TDE and not only the 10% producing "spaghettifications" and other "pancakes flambées".
It was only a decade later, in 1990, that the first TDE-compliant candidates were detected through NASA's "All Sky" X-ray survey of NASA's ROSAT satellite. Since then, more than a dozen candidates have been discovered, including more active sources in ultraviolet or visible for a reason that remained mysterious.
Finally, the theory of Luminet and Carter was confirmed by the observation of spectacular eruptions resulting from the accretion of stellar debris by a massive object located in the heart of the AGN (e.g. NGC 5128 or NGC 4438) but also in the heart of the Milky Way (Sgr A *). The TDE theory even explains the superluminous supernova SN 2015L, better known by the code name ASASSN-15lh, a marial supernova that exploded just before being absorbed beneath the horizon of a massive black hole.
Today, all known TDEs and TDE candidates have been listed in "The Open TDE Catalog" run by the Harvard CfA, which has had 87 entries since 1999.
In September 2016, a team from the University of Science and Technology of China in Hefei, Anhui, China, announced that, using data from NASA's Wide-field Infrared Survey Explorer, a stellar tidal disruption event was observed at a known black hole. Another team at Johns Hopkins University in Baltimore, Maryland, U.S., detected three additional events. In each case, astronomers hypothesized that the astrophysical jet created by the dying star would emit ultraviolet and X-ray radiation, which would be absorbed by dust surrounding the black hole and emitted as infrared radiation. Not only was this infrared emission detected, but they concluded that the delay between the jet's emission of ultraviolet and X-ray radiation and the dust's emission of infrared radiation may be used to estimate the size of the black hole devouring the star.
ASASSN-15lh (supernova designation SN 2015L) is an extremely bright astronomical transient discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN), with the appearance of a hypernova event. It was first detected on June 14, 2015, located within a faint galaxy in the southern constellation Indus, and is the brightest supernova-like object ever observed. At its peak, ASASSN-15lh was 570 billion times brighter than the Sun, and 20 times brighter than the combined light emitted by the Milky Way Galaxy. The emitted energy was exceeded by PS1-10adi.
The nature of ASASSN-15lh is disputed. The most popular explanations are that it is the most luminous type I supernova (hypernova) ever observed, or a tidal disruption event around a supermassive black hole. Other hypotheses include: gravitational lensing; a quark nova inside a Wolf–Rayet star; or a rapid magnetar spindown.Blitzar
Blitzars are a hypothetical type of astronomical object in which a spinning pulsar rapidly collapses into a black hole. They are proposed as an explanation for fast radio bursts (FRBs). The idea was proposed in 2013 by Heino Falcke and Luciano Rezzolla.Bright giant
The luminosity class II in the Yerkes spectral classification is given to bright giants. These are stars which straddle the boundary between ordinary giants and supergiants, based on the appearance of their spectra.CN star
A CN star is a star with strong cyanogen bands in its spectrum. Cyanogen is a simple molecule of one carbon atom and one nitrogen atom, with absorption bands around 388.9 and 421.6 nm. This group of stars was first noticed by Nancy G. Roman who called them 4150 stars.Electroweak star
An electroweak star is a theoretical type of exotic star, whereby the gravitational collapse of the star is prevented by radiation pressure resulting from electroweak burning, that is, the energy released by conversion of quarks to leptons through the electroweak force. This process occurs in a volume at the star's core approximately the size of an apple, containing about two Earth masses.The stage of life of a star that produces an electroweak star is theorized to occur after a supernova collapse. Electroweak stars are denser than quark stars, and may form when quark degeneracy pressure is no longer able to withstand gravitational attraction, but may still be withstood by electroweak burning radiation pressure. This phase of a star's life may last upwards of 10 million years.Frozen star (hypothetical star)
In astronomy, a frozen star, besides a disused term for a black hole, is a type of hypothetical star that, according to the astronomers Fred Adams and Gregory P. Laughlin, may appear in the future of the Universe when the metallicity of the interstellar medium is several times the solar value. Frozen stars would belong to a spectral class "H".GRB 110328A
Swift J164449.3+573451, initially referred to as GRB 110328A, and sometimes abbreviated to Sw J1644+57, was a tidal disruption event, the destruction of a star by a supermassive black hole. It was first detected by the Swift Gamma-Ray Burst Mission on March 28, 2011. The event occurred in the center of a small galaxy in the Draco constellation, about 3.8 billion light-years away.Studied by dozens of telescopes, it is one of the most puzzling cosmic blasts of high-energy radiation ever observed when it comes to brightness, variability and durability. It probably occurred when a star wandered too close to the central black hole in the galaxy, and was gravitationally torn apart and swallowed by it.
Timing considerations suggest that the tidally disrupted star was a white dwarf and not a regular main sequence star.Debris now encircles the black hole
in an accretion disk,
which launches bipolar jets at near the
speed of light.
Jet plasma emits the γ- and X-rays.
The beam of radiation from one of these jets points directly toward Earth,
enhancing the apparent brightness.
Repetitive dimming and softening of the X-rays
implies that the jet temporarily tilts away from us,
due to precession of the warped disk.The jets drive shocks
into the surrounding interstellar medium,
resulting in a radio to infrared
Detection of the relativistically expanding afterglow
confirmed the identity of the host galaxy.
Observed linear polarization
of the infrared radiation
is consistent with synchrotron emission
from the afterglow shock."This is truly different from any explosive event we have seen before," said Joshua Bloom of the University of California at Berkeley, the lead author of the study published in the June 2011 issue of Science.Helium-weak star
Helium-weak stars are chemically peculiar stars which have a weak helium lines for their spectral type. Their helium lines place them in a later (ie. cooler) spectral type then their hydrogen lines.Lambda Boötis star
A Lambda Boötis star is a type of peculiar star which has an unusually low abundance of iron peak elements in its surface layers. One possible explanation for this is that it is the result of accretion of metal-poor gas from a circumstellar disc, and a second possibility is the accretion of material from a hot Jupiter suffering from mass loss. The prototype is Lambda Boötis.Lead star
A lead star is a low-metallicity star with an overabundance of lead and bismuth as compared to other products of the S-process.List of hottest stars
This is a list of hottest stars so far discovered (excluding degenerate stars), arranged by decreasing temperature. The stars with temperatures higher than 60,000 K are included.List of stellar explosion types
Stellar explosion can refer to
type Ia supernova
Type Ib and Ic supernovae
Type II supernova
Supernova impostor, stellar explosions that appear similar to supernova, but do not destroy their progenitor stars
Luminous red nova, an explosion thought to be caused by stellar collision
solar flares are a minor type of stellar explosion
Tidal disruption event, the pulling apart of a star by tidal forcesOB star
OB stars are hot, massive stars of spectral types O or early-type B that form in loosely organized groups called OB associations. They are short lived, and thus do not move very far from where they formed within their life. During their lifetime, they will emit much ultraviolet radiation. This radiation rapidly ionizes the surrounding interstellar gas of the giant molecular cloud, forming an H II region or Strömgren sphere.
In lists of spectra the "spectrum of OB" refers to "unknown, but belonging to an OB association so thus of early type".Photometric-standard star
Photometric-standard stars are a series of stars that have had their light output in various passbands of photometric system measured very carefully. Other objects can be observed using CCD cameras or photoelectric photometers connected to a telescope, and the flux, or amount of light received, can be compared to a photometric-standard star to determine the exact brightness, or stellar magnitude, of the object.A current set of photometric-standard stars for UBVRI photometry was published by Arlo U. Landolt in 1992 in the Astronomical Journal.Q star
A Q-Star, also known as a grey hole, is a hypothetical type of a compact, heavy neutron star with an exotic state of matter. The Q stands for a conserved particle number. A Q-Star may be mistaken for a stellar black hole.Starfield (astronomy)
A starfield refers to a set of stars visible in an arbitrarily-sized field of view, usually in the context of some region of interest within the celestial sphere. For example: the starfield surrounding the stars Betelgeuse and Rigel could be defined as encompassing some or all of the Orion constellation.Stellar atmosphere
The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone.TDE
TDE may refer to:
Dichlorodiphenyldichloroethane (Tetrachlorodiphenylethane), an insecticide
Telefónica de España, London Stock Exchange symbol
The Daily Edited, an Australian luxury fashion brand specialising in monogrammable leather goods
The Dark Eye, a role-playing game
Tidal disruption event, an astronomical phenomenon near a supermassive black hole
Top Dawg Entertainment, a record label
Transparent Data Encryption, a technology employed by both Microsoft and Oracle to encrypt database content
Trinity Desktop Environment, an offshoot of the KDE 3.5 desktop environmentYellow giant
A yellow giant is a luminous giant star of low or intermediate mass (roughly 0.5–11 solar masses (M)) in a late phase of its stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature as low as 5,200-7500 K. The appearance of the yellow giant is from white to yellow, including the spectral types F and G. About 10.6 percent of all giant stars are yellow giants.