EO102
Encyclopedia
E0102 is the remnant of a supernova
that exploded in the neighbouring galaxy
known as the Small Magellanic Cloud
. The supernova was caused when a star
much more massive than the Sun
collapsed under its own gravity. The explosion
would have been visible from the Southern Hemisphere
of the Earth
over 1000 years ago. The appearance of E0102 is best explained by a model in which the ejecta
is shaped like a cylinder
that is being viewed almost exactly end-on. This model suggests that the explosion that created the E0102 remnant may itself have been strongly asymmetric
, consistent with the rapid kicks given to neutron stars after supernova explosions. Another possibility is that the star exploded into a disk of material formed when material was shed from the equator of the pre-supernova red giant
star. Such asymmetries have been observed in winds from lower mass red giants that form planetary nebulas. The remnant consists of an outer blast wave produced by the supernova, and an inner ring of cooler material. This inner ring is probably expanding ejecta from the explosion that is being heated by a shock wave
travelling backwards into the ejecta.
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
that exploded in the neighbouring galaxy
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
known as the Small Magellanic Cloud
Small Magellanic Cloud
The Small Magellanic Cloud is a dwarf galaxy. It has a diameter of about 7,000 light-years and contains several hundred million stars. It has a total mass of approximately 7 billion times the mass of our Sun....
. The supernova was caused when a star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
much more massive than the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
collapsed under its own gravity. The explosion
Explosion
An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...
would have been visible from the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
over 1000 years ago. The appearance of E0102 is best explained by a model in which the ejecta
Ejecta
Ejecta can mean:*In volcanology, particles that came out of a volcanic vent, traveled through the air or under water, and fell back on the ground surface or on the ocean floor...
is shaped like a cylinder
Cylinder
Cylinder most commonly refers to:* Cylinder , a three-dimensional geometric shapeCylinder may also refer to:-Science and technology:* Cylinder , the space in which a piston travels in an engine...
that is being viewed almost exactly end-on. This model suggests that the explosion that created the E0102 remnant may itself have been strongly asymmetric
Asymmetric
Something which is asymmetric displays asymmetry. Specific uses of the term may include:*Asymmetric relation for information on such relations in mathematics and set theory*Asymmetric warfare for information and theories of modern war...
, consistent with the rapid kicks given to neutron stars after supernova explosions. Another possibility is that the star exploded into a disk of material formed when material was shed from the equator of the pre-supernova red giant
Red giant
A red giant is a luminous giant star of low or intermediate mass in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower...
star. Such asymmetries have been observed in winds from lower mass red giants that form planetary nebulas. The remnant consists of an outer blast wave produced by the supernova, and an inner ring of cooler material. This inner ring is probably expanding ejecta from the explosion that is being heated by a shock wave
Shock wave
A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...
travelling backwards into the ejecta.