Stars Stars Astronomers measure the amount of light a star gives off in different colors. Hot stars give off more blue light than red and cool stars give off more red light than blue. Colored filters are used to measure different wavelengths of light from stars. The magnitude of the star is measured first through a blue or "B" filter. Then the star's magnitude is measured through a violet or "V" filter. The value of V is subtracted from B to get the B-V color index. ...more on Wikipedia about "B-V Colour"
Many of the brighter stars are given names which are known as Bayer designations. These designations, which were introduced by Johann Bayer in his star atlas Uranometria (named after Urania) in 1603, consist of a Greek letter followed by the genitive (in Latin) of the name of the constellation in which the star lies. See List of constellations for a list of constellations and the genitive forms of their names. ...more on Wikipedia about "Bayer designation"
Brown dwarfs are sub- stellar objects (~5 to 90 Jupiter masses) that do not fuse hydrogen-1 into helium and heavier elements in their cores, as do stars on the main sequence, but have fully convective surfaces and interiors, with no chemical differentiation by depth. There is some question as to whether brown dwarfs are required to have experienced fusion at some point in their history; in any event, brown dwarfs heavier than 13 Jupiter masses () do fuse deuterium. ...more on Wikipedia about "Brown dwarf"
Circumpolar stars are those stars which are located near the celestial poles of the celestial sphere, i.e. the poles in the equatorial coordinate system. As the Earth rotates, the sky appears to rotate; and most stars will be hidden below the horizon at some point in their circular paths. If, from a certain location, a star is near enough to the celestial pole that it never appears to go "under the horizon"; it will therefore be visible (from said location) for the entire night, on every day of the year. Some of the most circumpolar stars do not seem to engage in diurnal motion, at all. ...more on Wikipedia about "Circumpolar star"
In the convective overturn model, the core collapses faster and faster, exceding the speed of sound in the inside the star, and producing a supersonic shock wave. This shock wave explodes outward until it stalls when it reaches the neutrinosphere, where the pressure of the star collapsing inward exceeds the pressure of the neutrinos radiating outwards. This point produces heavier elements as the neutrinos are absorbed. ...more on Wikipedia about "Convective overturn"
Diurnal motion is an astronomical term referring to the apparent daily motion of stars in " orbit" around the Earth, caused by the Earth's rotation around its axis. It is a rotation around the axis between the two celestial poles. ...more on Wikipedia about "Diurnal motion"
A fusor is a term proposed to the IAU by Gibor Basri, Head of Astronomy at the University of Berkeley, to help clarify the nomenclature of celestial bodies. Under his definition a fusor would be "an object that achieves core fusion during its lifetime." ** ] ...more on Wikipedia about "Fusor (astronomy)"
The improper motion of a star refers to the change of its coordinates on the sky not originating from the motion of the star itself, as opposed to proper motion. ...more on Wikipedia about "Improper motion"
In astronomy, the interstellar medium (or ISM) is the matter and energy content that exists between the stars within a galaxy. The ISM plays a crucial role in astrophysics precisely because of its intermediate role between stellar and galactic scales. Stars form within the densest regions of the ISM, molecular clouds, and replenish the ISM with matter and energy through planetary nebulae, stellar winds, and supernovae. In turn, this interplay between stars and the ISM helps determine the rate at which a galaxy depletes its gaseous content, and therefore its lifespan of active star formation. ...more on Wikipedia about "Interstellar medium"
In astronomy, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium. All heavier elements are described in astronomy as " metals". ...more on Wikipedia about "Metallicity"
OB stars are the hotter, more massive stars within a star cluster. ...more on Wikipedia about "OB star"
Photometric standard stars are a series of stars that have had their light output in various passbands measured very carefully. Other objects can be observed using CCD cameras or photoelectric photometers connected to a telescope, and the flux, or amount of light received, can be compared to a photometric standard star to determine the exact brightness, or stellar magnitude, of the object. ...more on Wikipedia about "Photometric standard stars"
A pole star is a visible star that is approximately aligned with the Earth's axis of rotation; that is, a star that lies in the direction pointed to by one of Earth's poles. There are potentially both north and south pole stars, but whether there is either depends on the current stellar configuration. The term the pole star usually refers to the star Polaris (colloquially referred-to as the "north star") which is the current northern pole star. ...more on Wikipedia about "Pole star"
The proper motion of a star is the change in its position on the sky (the change in the direction in which we see it, as opposed to the radial velocity) after eliminating improper motions. ...more on Wikipedia about "Proper motion"
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Pulsars are rotating neutron stars that are observable as sources of electromagnetic radiation. The radiation intensity varies with a regular period, believed to correspond to the rotation period of the star. ...more on Wikipedia about "Pulsar"
A quasar (contraction of QUASi-stellAR radio sources) is an astronomical source of electromagnetic energy, including light, that dwarfs the energy output of the brightest stars. A Quasar may readily release energy in levels equal to the output of dozens of average galaxies combined. In optical telescopes, a quasar looks like a very faint star (i.e. it is a point source), and has a very high redshift. The general consensus is that this high redshift is cosmological, the result of Hubble's law, which implies that quasars must be very distant and must emit more energy than dozens of normal galaxies. ...more on Wikipedia about "Quasar"
The Red Clump is a region on the Hertzsprung-Russell diagram occupied primarily by metal-rich red giant stars. It is above/right relative to the main sequence and so consequently stars here are brighter than main sequence stars of the same surface temperature (or colder than stars of comparable luminosity). ...more on Wikipedia about "Red clump"
According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type. They comprise the vast majority of stars and have a diameter and mass of less than one-third that of the Sun (down to 0.08 solar masses, which are brown dwarfs) and a surface temperature of less than 3,500 K. They emit little light, sometimes as little as 1/10,000th that of the sun. Due to the slow rate at which they burn hydrogen, red dwarfs have an enormous estimated lifespan; estimates range from tens of billions up to trillions of years. Red dwarfs never initiate helium fusion and so cannot become red giants; the stars slowly contract and heat up until all the hydrogen is consumed. In any event, there has not been sufficient time since the Big Bang for red dwarfs to evolve off the main sequence. ...more on Wikipedia about "Red dwarf"
A solar twin is the informal name for a star with characteristics similar to our own Sun. Most scientists consider the prospect of having habitable planets is greater for solar twins than other stars. ...more on Wikipedia about "Solar twin"
A star is a massive body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. Unlike a planet, from which most light is reflected, a star emits light because of its intense heat. Scientifically, stars are defined as self-gravitating spheres of plasma in hydrostatic equilibrium, which generate their own energy through the process of nuclear fusion. Stellar astronomy is the study of stars. ...more on Wikipedia about "Star"
In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some of the more frequently quoted ones. Most of the recent catalogues are available in electronic format and can be freely downloaded from NASA's Astronomical Data Center and other places (see links at end). ...more on Wikipedia about "Star catalogue" This article is made on http://www.shortopedia.com
The International Astronomical Union (IAU) is the internationally recognised authority for assigning designations to stars (and other celestial bodies). Many of the star names in use today were inherited from the time before the IAU existed. Other names, mainly for variable stars (including novae and supernovae), are being added all the time. Most stars, however, have no name and are referred to, if at all, by means of catalogue numbers. This article briefly surveys some of the methods used to designate stars. ...more on Wikipedia about "Star designation"
In astronomy, starburst is a generic term to describe a region of space with a much higher than normal star formation. It is reserved for truly unusual objects. ...more on Wikipedia about "Starburst (astronomy)"
Over the past few centuries, a small number of stars have been named for individuals. It is common in astronomy for objects to be given names, in accordance with accepted astronomical naming conventions. However, most stars are not given proper names, relying on either long-standing traditional names (usually from the Arabic), or catalogue numbers. ...more on Wikipedia about "Stars named after people"
Stellar astronomy is the study of stars and the phenomena exhibited by the various forms/developmental stages of stars. ...more on Wikipedia about "Stellar astronomy" Please visit again shortopedia
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