#astrophysics definition
- Annihilation — A fundamental physical process of interaction and complete conversion of the mass of an elementary particle and its corresponding antiparticle into radiant energy (high-frequency photons) upon their collision. This phenomenon represents a specialized terminological variant for annihilation, being utilized primarily in astrophysics and quantum physics to describe early structural universe reactions or gamma radiation emissions from active galactic nuclei.
- Astrophysics — A branch of astronomy and modern physics that studies the physical properties, chemical composition, structure, dynamics, and evolution of celestial bodies (stars, planets, galaxies, nebulae) as well as the interstellar or intergalactic medium. This discipline applies the laws of thermodynamics, quantum mechanics, relativity, and electromagnetism to explain complex cosmic phenomena, from stellar nuclear fusion processes to cosmic microwave background radiation.
- Astrophotometry — A fundamental branch of practical astrophysics that deals with measuring the intensity, flux, and brightness of radiant energy (light) emitted by celestial bodies across different bands of the electromagnetic spectrum. Data obtained through astrophotometry (using photometers or CCD sensors) allow astronomers to determine cosmic distances, surface temperatures, rotational periods of variable stars, and to detect exoplanets via the transit method.
- Astrosphere — A bubble-like region of space surrounding a star, continuously generated and maintained by the stream of plasma ejected by that star (the stellar wind) and its magnetic field. This dynamic structure acts as a protective shield against interstellar dust and high-energy cosmic rays, extending up to the astropause, where the stellar wind pressure balances that of the surrounding interstellar medium; the heliosphere is the specific astrosphere of our Sun.
- Astrospectroscopy — An elite branch of practical astrophysics dealing with the photography, digital recording, and structural analysis of the electromagnetic radiation spectra emitted or absorbed by celestial bodies. By decomposing stellar light using prisms or diffraction gratings attached to telescopes, astrospectroscopy enables the determination of chemical composition, temperature, pressure, radial velocity, and magnetic field strength of objects in the universe.
- Astrospectroscopy — A fundamental field of astrophysics dealing with the qualitative and quantitative study of the electromagnetic radiation spectra emitted or absorbed by celestial bodies. This discipline analyzes spectral lines decomposed via diffraction gratings or prisms to deduce the chemical composition, effective temperature, surface gravity, radial velocity, and rotational motions of cosmic objects in the universe.