A failed supernova is an
astronomical event in
time domain astronomy in which a star suddenly brightens as in the early stage of a
supernova, but then does not increase to the massive flux of a supernova. They could be counted as a subcategory of
supernova imposters. They have sometimes misleadingly been called unnovae.
Overview
Failed supernovae are thought to create
stellar black holes by the collapsing of a
red supergiant
Red supergiants (RSGs) are stars with a supergiant luminosity class ( Yerkes class I) of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelgeuse and Ant ...
star in the early stages of a supernova. When the star can no longer support itself, the core collapses completely, forming a
stellar-mass black hole
A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. The process is observed as a hypernova explosion or as a g ...
, and consuming the nascent supernova without having the massive explosion. For a distant observer, the red supergiant star will seem to wink out of existence with little or no flare-up. The observed instances of these disappearances seem to involve
supergiant star
Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars s ...
s with masses above 17
solar masses
The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of ...
.
Failed supernovae are one of several events that theoretically signal the advent of a
black hole born from an extremely massive star, others including
hypernova
A hypernova (sometimes called a collapsar) is a very energetic supernova thought to result from an extreme core-collapse scenario. In this case, a massive star (>30 solar masses) collapses to form a rotating black hole emitting twin energetic je ...
e and long-duration
gamma-ray burst
In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten millise ...
s.
Structure and process
Theoretically, a
red supergiant
Red supergiants (RSGs) are stars with a supergiant luminosity class ( Yerkes class I) of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelgeuse and Ant ...
star may be too massive to explode into a
supernova, and collapse directly into being a
black hole, without the bright flash. They would however generate a burst of
gravitational waves. This process would occur in the higher mass red supergiants, explaining the absence of observed supernovae with such
progenitors.
[
]
List of failed supernovae candidates
References
External links
{{Supernovae
+
Astronomical events