42,772 articles
Gamma decay
Gamma decay is the emission of high-energy photons by an excited atomic nucleus dropping to a lower-energy state, leaving its proton and neutron numbers unchanged.
Gamma distribution
The gamma distribution is a continuous probability distribution for positive random variables defined by shape and scale parameters; it is used as a lifetime model and Bayesian prior.
Gamma Doradus variable
A Gamma Doradus variable is a main-sequence star of late-A to early-F type that pulsates in gravity modes, varying by up to 0.1 magnitude over 0.4 to 3 days.
Gamma Draconis
Gamma Draconis, also known as Eltanin, is an orange giant about 154.3 light-years away and the brightest star in Draco, the star Bradley used to discover the aberration of light in 1728.
Gamma Equulei
Gamma Equulei is a strongly magnetic Ap star in the constellation Equuleus, rotating once in about 97 years and pulsating as a roAp star every 12 minutes.
Gamma function
The gamma function, or Γ function, is a mathematical function extending the factorial to complex numbers, so Γ(z) = (z − 1)! for positive integers; Euler introduced it in 1729.
Gamma Geminorum
Gamma Geminorum, or Alhena, is a spectroscopic binary star in Gemini about 109 light-years from Earth, the third brightest point of light in the constellation after Pollux and Castor.
Gamma Leporis
Gamma Leporis is an F-type main-sequence star about 29 light-years from the Sun in the constellation Lepus, the brighter component of a wide double star with an orange dwarf companion.
Gamma matrices
The gamma matrices, or Dirac matrices, are square matrices satisfying the Clifford anticommutation relation {γ, γ} = 2η, appearing as coefficients of the Dirac equation in relativistic quantum mechanics.
Gamma Ophiuchi
Gamma Ophiuchi, cataloged as HD 161868, is a rapidly rotating A0V main-sequence star in Ophiuchus about 103 light-years away, known for one of the largest resolved debris disks around a nearby star.
Gamma Orionis
Gamma Orionis, officially named Bellatrix, Latin for "the Female Warrior", is a hot blue giant star in Orion, its third brightest, about 250 light years from Earth.
Gamma Pavonis
Gamma Pavonis is an F-type main-sequence star in the southern constellation Pavo, about 30 light-years away, notable for its low metallicity, old age, and asteroseismic studies.
Gamma Pegasi
Gamma Pegasi, or Algenib, is a blue subgiant star of spectral type B2 IV in the constellation Pegasus, about 391.5 light-years from Earth, and a hybrid pulsating variable.
Gamma process
The gamma process, or gamma subordinator, is a Lévy process with independent, nonnegative gamma-distributed increments, applied in reliability and as the time change behind the Variance Gamma option-pricing model.
Gamma ray
A gamma ray, also called gamma radiation, is the most energetic, shortest-wavelength electromagnetic radiation, emitted by excited atomic nuclei during radioactive decay and used in cancer therapy.
Gamma rays
Gamma rays are the highest-energy photons of the electromagnetic spectrum, a penetrating ionizing radiation described by Paul Villard in 1900 and emitted by nuclear processes, gamma-ray bursts, and pulsars.
Gamma regression
Gamma regression is a generalized linear model for strictly positive, right-skewed continuous outcomes such as costs and insurance claims, with variance proportional to the squared mean.
Gamma Serpentis
Gamma Serpentis, or Ainalhai, is a yellow-white F-type main-sequence star in the Serpens Caput half of the constellation Serpens, about 36.7 light-years away, with roughly 1.2 solar masses.
Gamma spectroscopy
Gamma spectroscopy, also called gamma ray spectrometry, is an analytical technique that identifies radionuclides by their characteristic gamma ray energies and quantifies their activity, using high-resolution detectors like HPGe.
Gamma Tauri
Gamma Tauri is a K-type giant star in the Hyades, the nearest open cluster to Earth, one of four prominent K giants that dominate its bright end.
Gamma Ursae Majoris
Gamma Ursae Majoris, formally named Phecda, is a white A-type star about 83 light-years from Earth, marking the lower-left corner of the Big Dipper's bowl.
Gamma Velorum
Gamma Velorum is a bright multiple star system in the constellation Vela whose brightest component, γ² Velorum, is a 78.5-day binary containing the closest Wolf–Rayet star to the Sun.
Gamma Virginis
Gamma Virginis, also known as Porrima, is a naked-eye binary star in Virgo made of two nearly identical F0 stars about 38 light-years away, orbiting each other every 169 years.
Gamma-alumina
Gamma-alumina (γ-Al2O3) is a metastable transition alumina with a defect spinel structure, formed by calcining boehmite at about 450–750 °C and the dominant industrial catalyst support for hydrotreating and automotive converters.
Gamma-Butyrolactone
Gamma-butyrolactone, also known as GBL or 1,4-butyrolactone, is a cyclic ester and widely used industrial solvent, notably in semiconductor manufacturing, that the body rapidly converts to the depressant GHB, placing it under controlled-substance regulation.
Gamma-ray burst
A gamma-ray burst is a brief, intense flash of gamma rays from explosions in distant galaxies; lasting milliseconds to minutes, they occur roughly once a day.
Gamma-ray imaging
Gamma-ray imaging is a set of techniques for mapping the direction, energy, and intensity of gamma rays, using coded masks, Compton telescopes, and pair-conversion telescopes.
Gamma-ray logging
Gamma-ray logging is a borehole geophysical method measuring gamma radiation in and around a drill hole, developed in the 1930s for uranium exploration and now among the most widely used well logs.
Gamma-terpinene
Gamma-terpinene (γ-terpinene), also known as p-mentha-1,4-diene, is a colorless monocyclic monoterpene hydrocarbon, C10H16, occurring widely in thyme, tea tree, citrus, and oregano oils, and serving as the biosynthetic precursor of thymol and carvacrol.
Gamma-valerolactone
Gamma-valerolactone (GVL, γ-valerolactone) is a water-miscible cyclic ester made from biomass-derived levulinic acid and used as a green solvent, fuel additive, and platform chemical for renewable fuels and polymers.