Stellar
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Stellar nucleosynthesis
Stellar nucleosynthesis is the collective term for the nucleosynthesis , or nuclear reactions, taking place in stars to build the nuclei of the elements heavier than hydrogen . Some small quantity of these reactions also occur on the stellar surface under various circumstances. For the creation of elements during the explosion of a star, the term supernova nucleosynthesis is used.Triple-alpha process
Overview of the triple-alpha process. The triple alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei ( alpha particles ) are transformed into carbon . [ 1 ] [ 2 ] Older stars start to accumulate helium produced by the proton–proton chain reaction and the carbon–nitrogen–oxygen cycle in their cores. The products of further nuclear fusion reactions of helium with hydrogen or another helium nucleus produce lithium-5 and beryllium-8 respectively, both of which are highly unstable and decay almost instantly back into smaller nuclei. [ 3 ] When the star starts to run out of hydrogen to fuse, the core of the star begins to collapse until the central temperature rises to ~100 × 10 6 K (8.6 keV) .
A supernova (abbreviated SN, plural SNe after supernovae) is a stellar explosion that is more energetic than a nova .
Supernova
Quark-nova
A quark-nova is a hypothetical type of supernova that could occur if a neutron star spontaneously collapsed to become a quark star .Quark star
A quark star or strange star is a hypothetical type of exotic star composed of quark matter , or strange matter .
Not a Quirk But a Quark ... a Quark Star!
Three exceptionally luminous supernovae explosions have been observed in recent years. One of them was first observed using a robotic telescope at the California Institute of Technology's (Caltech) Palomar Observatory. Data collected with Palomar's Samuel Oschin Telescope was transmitted from the remote mountain site in southern California to astronomers via the High-Performance Wireless Research and Education Network (HPWREN), funded by the National Science Foundation (NSF).
Hypernova
Eta Carinae , in the constellation of Carina, one of the nearer candidates for a future hypernova
Type II supernova
A Type II supernova (plural: supernovae ) results from the rapid collapse and violent explosion of a massive star . A star must have at least 9 times, and no more than 40–50 times the mass of the Sun for this type of explosion. [ 1 ] It is distinguished from other types of supernova by the presence of hydrogen in its spectrum . Type II supernovae are mainly observed in the spiral arms of galaxies and in H II regions , but not in elliptical galaxies . [ 2 ]Type Ib and Ic supernovae
The Type Ib supernova Supernova 2008D [ 1 ] [ 2 ] in galaxy NGC 2770 , shown in X-ray (left) and visible light (right), at the corresponding positions of the images. NASA image. [ 3 ] Types Ib and Ic supernovae are categories of stellar explosions that are caused by the core collapse of massive stars .
Possible new class of supernovae puts calcium in your bones
ScienceDaily (May 19, 2010) — In the past decade, robotic telescopes have turned astronomers' attention to scads of strange exploding stars, one-offs that may or may not point to new and unusual physics.