White dwarfStellar core remnantFor other uses, see White dwarf (other).A 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.
NovaA nova is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", Latin for "new"; the shortened form of "stella nova", Latin for "new star") that slowly fades over weeks or months. All observed novae involve white dwarfs in close binary systems, but causes of the dramatic appearance of a nova vary, depending on the circumstances of the two progenitor stars.
Binary starSystem of two stars orbiting each otherThe nearest binary star Alpha Centauri, as photographed by the Hubble Space TelescopeA binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars are among the most important objects in astrophysics because they allow direct measurement of stellar masses and test theories of stellar evolution.
Accretion diskAn accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward toward the central body.
Accretion (astrophysics)In astrophysics, accretion is the accumulation of matter into a massive object by gravitationally attracting more matter. If the matter is gaseous the result is an accretion disc. Accretion of solid matter such as dust will form larger solid objects. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.
Absolute magnitudeMeasure of the luminosity of celestial objectsIn astronomy, absolute magnitude (M) is a measure of the luminosity of a celestial object on an inverse logarithmicastronomical magnitude scale; the more luminous (intrinsically bright) an object, the lower its magnitude number.
HydrogenChemical element with atomic number 1 (H)–↑H↓Li(none) ← hydrogen → helium
GravityAttraction of masses and energyThe shapes of two massive galaxies in this image evolved under the effects of gravity.In physics, gravity (from Latin gravitas 'weight'), also known as gravitation or a gravitational interaction, is a fundamental interaction, which may be described as the force that draws material objects towards each other.
UltravioletUltraviolet radiation (UV; sometimes called ultraviolet light) is electromagnetic radiation of wavelengths of 100–400 nanometers, shorter than that of visible light, but longer than vacuum ultraviolet and extreme ultraviolet (radiation bands that overlap UV but share some properties with soft X-rays). UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun.
AstronomyScientific study of celestial objectsFor other uses, see Astronomy (other).Nine images relating to different branches of astronomy.Astronomy 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.
X-rayAn X-ray is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ranging from 10 nanometers to 10 picometers, corresponding to frequencies in the range of 30 petahertz to 30 exahertz (3×10 Hz to 3×10 Hz) and photon energies in the range of 100 eV to 100 keV, respectively.
Naked eyeNaked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collectingoptical instrument, such as a telescope or microscope, or eye protection. In astronomy, the naked eye may be used to observe celestial events and objects visible without equipment, such as conjunctions, passing comets, meteor showers, and the brightest asteroids, including 4 Vesta.
Mass transferMass transfer is the net movement of mass from one location (usually meaning stream, phase, fraction, or component) to another. Mass transfer occurs in many processes, such as absorption, evaporation, drying, precipitation, membrane filtration, and distillation. Mass transfer is used by different scientific disciplines for different processes and mechanisms.*As an Amazon Associate I earn from qualifying purchases.