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e. In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light ). The opposite change, a decrease in wavelength and increase in frequency and energy, is known as a blueshift, or negative redshift. The terms derive from the colours red and ...
Ap and Bp stars. Ap and Bp stars are chemically peculiar stars (hence the "p") of spectral types A and B which show overabundances of some metals, such as strontium, chromium, or europium. In addition, larger overabundances are often seen in praseodymium and neodymium. These stars have a much slower rotation than normal for A- and B-type stars ...
Markov (telescopic asterisms) (for example: Markov 1 in Hercules) MAXI — Monitor of All-sky X-ray Image. Mayall — Nicholas Mayall (for example: globular star cluster Mayall II orbiting Messier 31, the Andromeda galaxy) Mayer (open star clusters) McC — McCormick Observatory Catalog. MCG — Morphological Catalogue of Galaxies.
Stellar population. Artist's conception of the spiral structure of the Milky Way showing Baade's general population categories. The blue regions in the spiral arms are composed of the younger population I stars, while the yellow stars in the central bulge are the older population II stars. In reality, many population I stars are also found ...
Proxima Centauri, the closest star to the Sun, at a distance of 4.2 ly(1.3 pc), is a red dwarf. A red dwarfis the smallest kind of staron the main sequence. Red dwarfs are by far the most common type of fusingstar in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs cannot be ...
This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outside the atmosphere of Earth. The field of astronomy features an extensive vocabulary and a ...
Photometric system. In astronomy, a photometric system is a set of well-defined passbands (or optical filters ), with a known sensitivity to incident radiation. The sensitivity usually depends on the optical system, detectors and filters used. For each photometric system a set of primary standard stars is provided.
The unqualified term instability strip usually refers to a region of the Hertzsprung–Russell diagram largely occupied by several related classes of pulsating variable stars: Delta Scuti variables, SX Phoenicis variables, and rapidly oscillating Ap stars (roAps) near the main sequence; RR Lyrae variables where it intersects the horizontal branch; and the Cepheid variables where it crosses the ...