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Supernova Reference Libraries

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White Dwarf
2004-10-19 04:45:43

White Dwarf -- A white dwarf is a a star supported by electron degeneracy. A star like our Sun will become a white dwarf when it has exhausted its nuclear fuel. Near the end of its nuclear burning stage, such a star goes through a red giant phase and then expels most of its outer material (creating a planetary nebula) until only the hot (T > 100,000 K) core remains, which then settles...

Supernova Remnant
2004-10-19 04:45:42

Supernova Remnant -- A supernova remnant (SNR) is made up of the materials left behind by the gigantic explosion of a star in a supernova. There are two possible routes to this end: either a massive star may cease to generate fusion energy in its core, and collapse inward under the force of its own gravity, or a white dwarf star may accumulate material from a companion star until it reaches...

Supernova
2004-10-19 04:45:42

Supernova -- A supernova is a star that increases its brightness drastically within a matter of days, making it appear as if a "new" star was born (hence "nova"). The "super" prefix distinguishes it from a mere nova, which also involves a star increasing in brightness, though to a lesser extent and through a much different mechanism. Astronomers have classified supernovae in several...

Stellar Evolution
2004-10-19 04:45:42

Stellar Evolution -- Stellar evolution is the process of formation, life, and death of stars. It is one of the major topics of cosmogony. Star Birth and Life A star starts out as an enormous cloud of gas and dust many light-years across. Star formation begins when the cloud begins to condense under its own gravity. The processes that initiate this contraction are not fully understood....

Nova
2004-10-19 04:45:42

Nova -- A nova is an enormous nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star. When a white dwarf has a close companion star, the companion will often begin to have its outer atmosphere drawn away from it by the white dwarf's gravity as the companion star ages and expands into a red giant. The gases so captured consist primarily of hydrogen...

Magnetar
2004-10-19 04:45:41

Magnetar -- A magnetar is a neutron star with a strong magnetic field. The theory around these objects was formulated by Robert Duncan and Christopher Thompson. When in a supernova a star collapses to a neutron star, its magnetic field increases dramatically in strength. Duncan and Thompson calculated that the magnetic field of a neutron star, normally an already enormous 1012 tesla...

Hypernova
2004-10-19 04:45:41

Hypernova -- A hypernova is a theoretical type of supernova produced when exceptionally large stars collapse at the end of their lifespan. In a hypernova, the core of the star collapses directly into a black hole and two extremely energetic jets of plasma are emitted from its rotational poles at nearly light speed. These jets emit intense gamma rays, and are a candidate explanation for...

Gamma-Ray Burst
2004-10-19 04:45:41

Gamma-Ray Burst -- In astronomy, Gamma-ray bursters (GRBs) are flashes of gamma rays that last from seconds to hours, the longer ones being followed by several days of X-ray afterglow. They occur at random positions in the sky several times each day. They are now believed to result from tremendous explosions in far away galaxies, during the creation of a black hole from a dying star or two...

Supernova 1987a
2004-10-19 04:45:40

Supernova 1987a -- Supernova 1987a was a supernova in the Large Magellanic Cloud, a nearby dwarf galaxy. It occurred approximately 50 kiloparsecs from Earth, the closest supernova since Supernova 1604, which occurred in the Milky Way itself. The light from the supernova reached Earth on February 23, 1987. Its brightness peaked in May with a magnitude of about 3 and slowly declined in...

Crab Nebula
2004-10-19 04:45:40

Crab Nebula -- The Crab Nebula (Messier 1, NGC 1952) is the object the which started Charles Messier logging non-cometary objects on his Messier Catalog. It is the expanding cloud of gas thrown off in the explosion that gave rise to the 1054 supernova recorded by Chinese astronomers, now more than 6 light years across (the nebula is currently expanding at 1000 km/sec and the total mass of...

Word of the Day
bretelles
  • In dressmaking, straps running from the belt in front over the shoulders to the belt in the back, with more or less elaboration of trimming and outline. They usually broaden at the shoulder and narrow toward the waist.
The word 'bretelles' comes from a French word meaning 'braces'.