Neutron starA neutron star is the gravitationally collapsed core of a massive supergiant star. It results from the supernova explosion of a massive star—combined with gravitational collapse—that compresses the core past white dwarf star density to that of atomic nuclei. Surpassed only by black holes, neutron stars are the second-smallest and second-densest known class of stellar objects.
White dwarfA white dwarf is a very dense type of star: in an Earth-sized volume, it packs a mass that is comparable to the Sun. A white dwarf radiates light from residual heat and eventual crystallization, not from nuclear fusion. Stars like the Sun, whose mass is not high enough to collapse into a neutron star or black hole, are expected to become white dwarf stars later in their evolution.
Black holeCompact astronomical bodyAn image of the core region of Messier 87, a supermassive black hole, processed from an array of eight radio telescopes known as the EHT with colours indicating brightness temperatureSimulated view of a nonspinning, uncharged black hole in front of the Large Magellanic Cloud. The gravitational lensing effect produces two enlarged but distorted views of the Cloud. Across the top, the Milky Way disk appears distorted into an arc.
Stellar evolutionStellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the current age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds.
Exotic starAn exotic star is a hypothetical compact star composed of exotic matter (something not made of electrons, protons, neutrons, or muons), and balanced against gravitational collapse by degeneracy pressure or other quantum properties.
MatterSomething that has mass and volumeHydrogen in its plasma state is the most abundant ordinary matter in the universe.In physical science, matter is anything that has mass and occupies space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles.
DensityDensity (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D (or d) can also be used: ρ=mV,{\displaystyle ho ={\frac {m}{V}},} where ρ is the density, m is the mass, and V is the volume.
RadiusIn classical geometry, a radius (pl.: radii or radiuses) of a circle or sphere is any of the line segments from its center to its perimeter (circle) or surface (sphere), and, in more modern usage, it is also their length. The radius of a regular polygon is the line segment or distance from its center to any of its vertices. The name comes from the Latinradius, meaning ray but also the spoke of a chariot wheel.
AtomSmallest unit of a chemical elementAtoms are the basic particles of the chemical elements and the fundamental building blocks of matter. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper.
AstronomyAstronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry to explain their origin and their overall evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation.
Fast radio burstIn radio astronomy, a fast radio burst (FRB) is a transient radio wave of duration ranging from a fraction of a millisecond, for an ultra-fast radio burst, to 3 seconds, caused by a high-energy astrophysical process that is not yet understood. Astronomers estimate the average FRB releases as much energy in a millisecond as the Sun puts out in three days.
MassAmount of matter present in an objectMass is an intrinsic physical quantity of a body which in modern physics is generally defined as the strength of an object's gravitational attraction to other bodies. The unit of mass in the International System of Units (SI) is the kilogram (kg). Mass can also be understood as a measure of the energy content of a body (see E=mc²).*As an Amazon Associate I earn from qualifying purchases.