In February of 1987, astronomers saw the closest supernova of modern times; it was in the Large Magellanic Cloud, a neighboring dwarf galaxy. This supernova, named SN 1987A, is incontrovertible...
https://www.astrophysicsspectator.com/topics/supernovae/CoreCollapse1987a.html
A core-collapse supernova releases most of its energy as neutrinos. This theoretical conclusion is confirmed by a single event, the supernova seen in the Large Magellanic Cloud in 1987. Large...
https://www.astrophysicsspectator.com/topics/supernovae/CoreCollapseNeutrinos1987a.html
The most energetic supernovae are powered by gravitational potential energy. Once a massive star consumes all of its thermonuclear fuel, it is unable to support itself against its own gravity. ...
https://www.astrophysicsspectator.com/topics/supernovae/SupernovaeCoreCollapse.html
Carbon and oxygen are converted into nickel in a white dwarf through a complex network of reactions. The incremental changes tend to follow the series of atomic nuclei that are multiples in compo...
https://www.astrophysicsspectator.com/topics/supernovae/ThermonuclearBurning.html
The thermonuclear energy locked inside a white dwarf is sufficient to blow the star apart. In particular, white dwarfs composed of carbon and oxygen, which are more common and contain more ther...
https://www.astrophysicsspectator.com/topics/supernovae/ThermonuclearEnergetics.html
Most type Ia supernovae are attributed to the thermonuclear explosion of white dwarfs. A star becomes a white dwarf before it has completely consumed its thermonuclear fuel. The amount of the...
https://www.astrophysicsspectator.com/topics/supernovae/SupernovaeThermonuclear.html
Theorists divide supernovae into two types: core-collapse supernovae and thermonuclear detonation supernovae. The first type occurs when a massive star exhausts its thermonuclear fuel. The se...
Neutron stars are strong neutrinos emitters. The power radiated by a neutron star as neutrinos far outstrips the power radiated as x-rays from the photosphere. Three processes are responsible...
https://www.astrophysicsspectator.com/topics/degeneracy/NeutronStarNeutrinoCooling.html
The principal way that a degenerate dwarf cools is through the emission of neutrinos. Unlike the main-sequence stars, which generate neutrinos as part of their thermonuclear generation of power...
https://www.astrophysicsspectator.com/topics/degeneracy/DegenerateDwarfNeutrinoCooling.html
Astrophysicists generally assume that the compact objects at the centers of galaxies are black holes. Why couldn't these objects be massive neutron stars or some other type of degenerate body?�...
https://www.astrophysicsspectator.com/topics/degeneracy/BlackHoleInevitability.html
The American Physical Society is pleased with the bit of pork congress is giving the National Science Foundation and the National Aeronautic and Space Administration in the American Recovery and ...
https://www.astrophysicsspectator.com/commentary/2009/Commentary20090130.html
The radii of degenerate dwarfs and of neutron stars are fundamentally linked to the fundamental constants of physics. The neutron star is about the size of a black hole of comparable mass. Th...
https://www.astrophysicsspectator.com/topics/degeneracy/DegeneracyPressureRadius.html
Degeneracy pressure—the pressure caused by the Pauli exclusion principle of quantum mechanics—is manifested by four types of astronomical object: the giant gaseous planet, the brown dwarf, th...
Jupiter and Saturn have a fundamental link to the degenerate (white) dwarfs and neutron stars: all of these objects are supported against gravitational collapse by a pressure generated through th...
https://www.astrophysicsspectator.com/topics/degeneracy/DegeneracyPressure.html
Objects supported by electron degeneracy pressure span a broad range of masses. The low-mass end of this range, which is near the mass of Saturn, is set by the transition from pressure exerted ...
https://www.astrophysicsspectator.com/topics/degeneracy/DegeneracyPressureMassLimits.html
The Chinese government is investing in a rocket engine called the Emdrive that generates thrust with microwaves. There appears to be a slight problem, however, with this engine: it violates con...
https://www.astrophysicsspectator.com/commentary/2008/Commentary20081001.html
The stars and planets have radii that are set by the balance of internal pressure against self-gravity. Because internal pressure has several sources, the stars and planets fall into several clas...
https://www.astrophysicsspectator.com/topics/overview/SizeStarsPlanets.html
The Large Hadron Collider at CERN, a machine that accelerates protons to very high energies and then bangs them together, began operating on September 10, 2008. Some believe this machine threaten...
https://www.astrophysicsspectator.com/commentary/2008/Commentary20080917.html
The structure of a brown dwarf is set by degeneracy pressure. Unlike a star, where the mass sets both the radius and the photospheric temperature, a brown dwarf has a radius and temperature tha...
https://www.astrophysicsspectator.com/topics/degeneracy/BrownDwarfStructure.html
Recently some people have claimed that the Sun is entering a new Maunder Minimum—a decades-long period of few sunspots—and that this will cause the Earth's atmosphere to cool. The Sun is ce...
https://www.astrophysicsspectator.com/commentary/2008/Commentary20080903.html
A class of object, long predicted by astrophysicists, sits in the mass range between the giant gaseous planets and the M dwarf stars. These objects are called brown dwarfs. They are massive e...
https://www.astrophysicsspectator.com/topics/degeneracy/BrownDwarf.html
In the nineteenth century, astronomers recognized that stars could be classified by their spectra into a handful of types. Over time, this system was refined to characterize a star in terms of ...
https://www.astrophysicsspectator.com/topics/observation/StellarTypes.html
The magnitude system used by astronomers ranks stars by brightness, with the brightest stars having the lowest values of magnitude. A star's magnitude is generally measured after the starlight ...
https://www.astrophysicsspectator.com/topics/observation/MagnitudesAndColors.html
The HR diagram of the stars within 10 parsecs is presented on this page. The diagram reveals that we are surrounded largely by two types of star: dark main-sequence stars and degenerate dwarfs....
https://www.astrophysicsspectator.com/topics/stars/HertzsprungRussellLocalStars.html
Little more than 350 stars are known to be within 10 parsecs of the Sun. Most of these are too dim to see with the unaided eye. Several, however, are among the brightest stars in the night sky...
https://www.astrophysicsspectator.com/tables/ClosestBrightStars.html
The nearby stars are of all ages, which gives them a broad variety of luminosities and colors. To see stars of the same age, to see the effects of mass and composition alone on a star's color a...
https://www.astrophysicsspectator.com/topics/stars/HertzsprungRussellClusters.html