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Binary star

Index Binary star

A binary star is a star system consisting of two stars orbiting around their common barycenter. [1]

197 relations: A-type main-sequence star, Absolute magnitude, Accretion (astrophysics), Accretion disk, Albireo, Algol, Algol paradox, Alpha Centauri, Alpha Crucis, Alvan Graham Clark, AM Canum Venaticorum star, Andromeda Galaxy, Angular momentum, Angular resolution, Antares, Apparent magnitude, Astrometry, Astronomy & Astrophysics, Astrophysics, Atmosphere of Earth, Auriga (constellation), B-type main-sequence star, Barycenter, Bayer designation, Benedetto Castelli, Beta Centauri, Beta Lyrae, BG Geminorum, Big Dipper, Binary mass function, Binary star, Binary stars in fiction, Binary system, Binoculars, Biosphere, Black hole, Canis Major, Canis Minor, Castor (star), Cataclysmic variable star, Centaurus, Center of mass, Chandrasekhar limit, Circle, Circumbinary planet, CNO cycle, Comes, Compact star, Conservation law, Conservation of energy, ..., Constellation, Contact binary, Cosmic distance ladder, Crux, Cygnus (constellation), Cygnus X-1, D. Reidel, Degenerate matter, Density, Doppler effect, Double star, Earth's orbit, Eclipse, Electromagnetic radiation, Ellipse, Epsilon Aurigae, Eta Carinae, Exoplanet, Félix Savary, Friedrich Bessel, Galileo Galilei, Gamma Cephei, Gemini (constellation), Geminiano Montanari, Ghoul, Giant star, Giovanni Battista Riccioli, Gravitational energy, Gravitational lens, Gravity, HD 30453, Hubble Space Telescope, Interferometry, Johannes Kepler, John Michell, Kepler (spacecraft), Kepler's laws of planetary motion, KOI-74, KOI-81, Lagrangian point, Large Magellanic Cloud, Light curve, List of brightest stars, Log-normal distribution, Luminosity, Luminous blue variable, Lunar theory, Lyra, Main sequence, Mass, Mass transfer, Microsoft PowerPoint, Milky Way, Mizar and Alcor, Molecular cloud, Monotonic function, Monthly Notices of the Royal Astronomical Society, Mount Wilson Observatory, NASA, Neutron star, Nightfall (Asimov novelette and novel), NN Serpentis, Nova, Nuclear fusion, Optical resolution, Orbit, Orbital eccentricity, Orbital elements, Orbital period, Parallax, Parsec, Perpendicular, Perseus (constellation), Photometry (astronomy), Planet, Planetary nebula, Polar coordinate system, Position angle, Procyon, Proper motion, Protoplanet, Protostar, Proxima Centauri, PSR B1620-26, Pulsar, R Aquarii, Radial velocity, Red dwarf, Redshift, Relativistic beaming, Robert Grant Aitken, Roche lobe, Rotational Brownian motion (astronomy), Science fiction, Semi-major and semi-minor axes, Sirius, Small Magellanic Cloud, SN 1572, Solar eclipse, Spectral line, Spectrometer, Spectroscopy, Star, Star formation, Star system, Star Wars, Stellar atmosphere, Stellar black hole, Stellar classification, Stellar collision, Stellar evolution, Stellar kinematics, Stellar mass, Stellar population, Stellar wind, Subgiant, Sun, Supernova, Symbiotic binary, Tatooine, Telescope, Three-body problem, Tolman–Oppenheimer–Volkoff limit, Transit (astronomy), Triangulum Galaxy, Trigonometric functions, Two-body problem in general relativity, Tycho Brahe, Type Ia supernova, United States Naval Observatory, Ursa Major, Variable star, Visual binary, W Ursae Majoris, Washington Double Star Catalog, White dwarf, William Herschel, Wolf–Rayet star, Wolfram Demonstrations Project, X-ray, X-ray binary, Xi Ursae Majoris, Zeta Reticuli, Zeta Ursae Majoris, 104 Aquarii, 107 Aquarii, 61 Cygni. Expand index (147 more) »

A-type main-sequence star

An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V. These stars have spectra which are defined by strong hydrogen Balmer absorption lines.

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Absolute magnitude

Absolute magnitude is a measure of the luminosity of a celestial object, on a logarithmic astronomical magnitude scale.

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Accretion (astrophysics)

In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk.

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Accretion disk

An accretion disk is a structure (often a circumstellar disk) formed by diffused material in orbital motion around a massive central body.

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Albireo is the traditional name for the double star also designated Beta Cygni (β Cygni, abbreviated Beta Cyg, β Cyg), although the International Astronomical Union now regards the name as only applying to the brightest component.

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Algol, designated Beta Persei (β Persei, abbreviated Beta Per, β Per), known colloquially as the Demon Star, is a bright multiple star in the constellation of Perseus and one of the first non-nova variable stars to be discovered.

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Algol paradox

In stellar astronomy, the Algol paradox is a paradoxical situation when elements of a binary star seem to evolve in discord with the established theories of stellar evolution.

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Alpha Centauri

Alpha Centauri (α Centauri, abbreviated Alf Cen or α Cen) is the star system closest to the Solar System, being from the Sun.

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Alpha Crucis

Alpha Crucis (α Crucis, abbreviated Alpha Cru, α Cru) is a multiple star system located 321 light-years from the Sun in the constellation of Crux and part of the asterism known as the Southern Cross.

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Alvan Graham Clark

Alvan Graham Clark (July 10, 1832 – June 9, 1897) was an American astronomer and telescope-maker.

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AM Canum Venaticorum star

An AM CVn star, or AM Canum Venaticorum star, is a rare type of cataclysmic variable star named after their type star, AM Canum Venaticorum.

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Andromeda Galaxy

The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth, and the nearest major galaxy to the Milky Way.

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Angular momentum

In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum.

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Angular resolution

Angular resolution or spatial resolution describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution.

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Antares, also designated Alpha Scorpii (α Scorpii, abbreviated Alpha Sco, α Sco), is on average the fifteenth-brightest star in the night sky, and the brightest star in the constellation of Scorpius.

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Apparent magnitude

The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.

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Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies.

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Astronomy & Astrophysics

Astronomy & Astrophysics is a peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics.

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Astrophysics is the branch of astronomy that employs the principles of physics and chemistry "to ascertain the nature of the astronomical objects, rather than their positions or motions in space".

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Atmosphere of Earth

The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity.

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Auriga (constellation)

Auriga is one of the 88 modern constellations; it was among the 48 constellations listed by the 2nd-century astronomer Ptolemy.

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B-type main-sequence star

A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars are extremely luminous and blue.

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The barycenter (or barycentre; from the Ancient Greek βαρύς heavy + κέντρον centre) is the center of mass of two or more bodies that are orbiting each other, which is the point around which they both orbit.

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Bayer designation

A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name.

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Benedetto Castelli

Benedetto Castelli (1578 – 9 April 1643), born Antonio Castelli, was an Italian mathematician.

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Beta Centauri

Beta Centauri (β Centauri, abbreviated Beta Cen, β Cen), also named Agena and Hadar, is a triple star system in the southern constellation of Centaurus.

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Beta Lyrae

Beta Lyrae (Latinized from β Lyrae, abbreviated Beta Lyr, β Lyr), also named Sheliak, is a binary star system approximately from the Sun in the constellation of Lyra.

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BG Geminorum

BG Geminorum is an eclipsing binary star system in the constellation Gemini.

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Big Dipper

The Big Dipper (US) or the Plough (UK) is an asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude.

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Binary mass function

In astronomy, the binary mass function or simply mass function is a function that constrains the mass of the unseen component (typically a star or exoplanet) in a single-lined spectroscopic binary star or in a planetary system.

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Binary star

A binary star is a star system consisting of two stars orbiting around their common barycenter.

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Binary stars in fiction

A significant number of science fiction works have explored the imaginative possibilities of binary or multiple star systems.

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Binary system

A binary system is a system of two astronomical bodies which are close enough that their gravitational attraction causes them to orbit each other around a barycenter (also see animated examples).

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Binoculars or field glasses are two telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects.

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The biosphere (from Greek βίος bíos "life" and σφαῖρα sphaira "sphere") also known as the ecosphere (from Greek οἶκος oîkos "environment" and σφαῖρα), is the worldwide sum of all ecosystems.

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Black hole

A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light—can escape from inside it.

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Canis Major

Canis Major is a constellation in the southern celestial hemisphere.

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Canis Minor

Canis Minor is a small constellation in the northern celestial hemisphere.

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Castor (star)

Castor, also designated Alpha Geminorum (α Geminorum, abbreviated Alpha Gem, α Gem) is the second-brightest star in the constellation of Gemini and one of the brightest stars in the night sky.

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Cataclysmic variable star

Cataclysmic variable stars (CV) are stars which irregularly increase in brightness by a large factor, then drop back down to a quiescent state.

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Centaurus is a bright constellation in the southern sky.

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Center of mass

In physics, the center of mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero, or the point where if a force is applied it moves in the direction of the force without rotating.

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Chandrasekhar limit

The Chandrasekhar limit is the maximum mass of a stable white dwarf star.

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A circle is a simple closed shape.

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Circumbinary planet

A circumbinary planet is a planet that orbits two stars instead of one.

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CNO cycle

The CNO cycle (for carbon–nitrogen–oxygen) is one of the two known sets of fusion reactions by which stars convert hydrogen to helium, the other being the proton–proton chain reaction.

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"Comes", plural "comites", is the Latin word for "companion", either individually or as a member of a collective denominated a "comitatus", especially the suite of a magnate, being in some instances sufficiently large and/or formal to justify specific denomination, e. g. a "cohors amicorum".

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Compact star

In astronomy, the term "compact star" (or "compact object") refers collectively to white dwarfs, neutron stars, and black holes.

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Conservation law

In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves over time.

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Conservation of energy

In physics, the law of conservation of energy states that the total energy of an isolated system remains constant, it is said to be ''conserved'' over time.

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A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere, typically representing animals, mythological people or gods, mythological creatures, or manufactured devices.

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Contact binary

In astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes.

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Cosmic distance ladder

The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects.

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Crux is a constellation located in the southern sky in a bright portion of the Milky Way.

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Cygnus (constellation)

Cygnus is a northern constellation lying on the plane of the Milky Way, deriving its name from the Latinized Greek word for swan.

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Cygnus X-1

Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus, and the first such source widely accepted to be a black hole.

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D. Reidel


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Degenerate matter

Degenerate matter is a highly dense state of matter in which particles must occupy high states of kinetic energy in order to satisfy the Pauli exclusion principle.

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The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume.

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Doppler effect

The Doppler effect (or the Doppler shift) is the change in frequency or wavelength of a wave in relation to observer who is moving relative to the wave source.

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Double star

In observational astronomy, a double star or visual double is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope.

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Earth's orbit

Earth's orbit is the trajectory along which Earth travels around the Sun.

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An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer.

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Electromagnetic radiation

In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space-time, carrying electromagnetic radiant energy.

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In mathematics, an ellipse is a curve in a plane surrounding two focal points such that the sum of the distances to the two focal points is constant for every point on the curve.

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Epsilon Aurigae

Epsilon Aurigae (ε Aurigae, abbreviated Eps Aur, ε Aur) is a multiple star system in the northern constellation of Auriga.

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Eta Carinae

Eta Carinae (η Carinae, abbreviated to η Car), formerly known as Eta Argus, is a stellar system containing at least two stars with a combined luminosity greater than five million times that of the Sun, located around 7,500 light-years (2,300 parsecs) distant in the constellation Carina.

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An exoplanet or extrasolar planet is a planet outside our solar system.

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Félix Savary

Félix Savary, who was born on 4 October 1797 in Paris and died on 15 July 1841 in Estagel, was a French astronomer.

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Friedrich Bessel

Friedrich Wilhelm Bessel (22 July 1784 – 17 March 1846) was a German astronomer, mathematician, physicist and geodesist.

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Galileo Galilei

Galileo Galilei (15 February 1564Drake (1978, p. 1). The date of Galileo's birth is given according to the Julian calendar, which was then in force throughout Christendom. In 1582 it was replaced in Italy and several other Catholic countries with the Gregorian calendar. Unless otherwise indicated, dates in this article are given according to the Gregorian calendar. – 8 January 1642) was an Italian polymath.

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Gamma Cephei

Gamma Cephei (γ Cephei, abbreviated Gamma Cep, γ Cep) is a binary star system approximately 45 light-years away in the constellation of Cepheus.

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Gemini (constellation)

Gemini is one of the constellations of the zodiac.

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Geminiano Montanari

Geminiano Montanari. Geminiano Montanari (June 1, 1633 – October 13, 1687) was an Italian astronomer, lens-maker, and proponent of the experimental approach to science.

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A ghoul is a demon or monster in Arabian mythology, associated with graveyards and consuming human flesh.

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Giant star

A giant star is a star with substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature.

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Giovanni Battista Riccioli

Giovanni Battista Riccioli (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order.

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Gravitational energy

Gravitational energy is the potential energy a body with mass has in relation to another massive object due to gravity.

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Gravitational lens

A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer.

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Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or gravitate toward) one another.

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HD 30453

HD 30453 (HR 1528) is a double-lined spectroscopic binary in the northern constellation of Auriga.

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Hubble Space Telescope

The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.

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Interferometry is a family of techniques in which waves, usually electromagnetic waves, are superimposed causing the phenomenon of interference in order to extract information.

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Johannes Kepler

Johannes Kepler (December 27, 1571 – November 15, 1630) was a German mathematician, astronomer, and astrologer.

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John Michell

John Michell (25 December 1724 – 29 April 1793) was an English natural philosopher and clergyman who provided pioneering insights in a wide range of scientific fields, including astronomy, geology, optics, and gravitation.

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Kepler (spacecraft)

Kepler is a space observatory launched by NASA to discover Earth-size planets orbiting other stars.

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Kepler's laws of planetary motion

In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.

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KOI-74 is an eclipsing binary star in the constellation of Cygnus.

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KOI-81 is an eclipsing binary star in the constellation of Cygnus.

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Lagrangian point

In celestial mechanics, the Lagrangian points (also Lagrange points, L-points, or libration points) are positions in an orbital configuration of two large bodies, wherein a small object, affected only by the gravitational forces from the two larger objects, will maintain its position relative to them.

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Large Magellanic Cloud

The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way.

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Light curve

In astronomy, a light curve is a graph of light intensity of a celestial object or region, as a function of time.

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List of brightest stars

This is a list of the brightest naked eye stars to +2.50 magnitude, as determined by their maximum, total, or combined apparent visual magnitudes as seen from Earth.

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Log-normal distribution

In probability theory, a log-normal (or lognormal) distribution is a continuous probability distribution of a random variable whose logarithm is normally distributed.

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In astronomy, luminosity is the total amount of energy emitted per unit of time by a star, galaxy, or other astronomical object.

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Luminous blue variable

Luminous blue variables (LBVs) are massive evolved stars that show unpredictable and sometimes dramatic variations in both their spectra and brightness.

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Lunar theory

Lunar theory attempts to account for the motions of the Moon.

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Lyra (Latin for lyre, from Greek λύρα) is a small constellation.

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Main sequence

In astronomy, the main sequence is a continuous and distinctive band of stars that appear on plots of stellar color versus brightness.

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Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.

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Mass transfer

Mass transfer is the net movement of mass from one location, usually meaning stream, phase, fraction or component, to another.

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Microsoft PowerPoint

Microsoft PowerPoint (or simply PowerPoint) is a presentation program, created by Robert Gaskins and Dennis Austin at a software company named Forethought, Inc.

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Milky Way

The Milky Way is the galaxy that contains our Solar System.

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Mizar and Alcor

Mizar and Alcor are two stars forming a naked eye double in the handle of the Big Dipper (or Plough) asterism in the constellation of Ursa Major.

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Molecular cloud

A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H2).

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Monotonic function

In mathematics, a monotonic function (or monotone function) is a function between ordered sets that preserves or reverses the given order.

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Monthly Notices of the Royal Astronomical Society

Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.

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Mount Wilson Observatory

The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States.

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The National Aeronautics and Space Administration (NASA) is an independent agency of the executive branch of the United States federal government responsible for the civilian space program, as well as aeronautics and aerospace research.

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Neutron star

A neutron star is the collapsed core of a large star which before collapse had a total of between 10 and 29 solar masses.

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Nightfall (Asimov novelette and novel)

"Nightfall" is a 1941 science fiction novelette by American writer Isaac Asimov about the coming of darkness to the people of a planet ordinarily illuminated by sunlight at all times.

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NN Serpentis

NN Serpentis (abbreviated NN Ser) is an eclipsing post-common envelope binary system approximately 1670 light-years away.

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A nova (plural novae or novas) or classical nova (CN, plural CNe) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star, that slowly fades over several weeks or many months.

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Nuclear fusion

In nuclear physics, nuclear fusion is a reaction in which two or more atomic nuclei come close enough to form one or more different atomic nuclei and subatomic particles (neutrons or protons).

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Optical resolution

Optical resolution describes the ability of an imaging system to resolve detail in the object that is being imaged.

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In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.

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Orbital eccentricity

The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle.

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Orbital elements

Orbital elements are the parameters required to uniquely identify a specific orbit.

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Orbital period

The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.

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Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.

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The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.

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In elementary geometry, the property of being perpendicular (perpendicularity) is the relationship between two lines which meet at a right angle (90 degrees).

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Perseus (constellation)

Perseus is a constellation in the northern sky, being named after the Greek mythological hero Perseus.

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Photometry (astronomy)

Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation.

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A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.

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Planetary nebula

A planetary nebula, abbreviated as PN or plural PNe, is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.

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Polar coordinate system

In mathematics, the polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a reference point and an angle from a reference direction.

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Position angle

Position angle, usually abbreviated PA, is the convention for measuring angles on the sky in astronomy.

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Procyon, also designated Alpha Canis Minoris (α Canis Minoris, abbreviated Alpha CMi, α CMi), is the brightest star in the constellation of Canis Minor.

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Proper motion

Proper motion is the astronomical measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars.

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A protoplanet is a large planetary embryo that originated within a protoplanetary disc and has undergone internal melting to produce a differentiated interior.

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A protostar is a very young star that is still gathering mass from its parent molecular cloud.

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Proxima Centauri

Proxima Centauri, or Alpha Centauri C, is a red dwarf, a small low-mass star, about from the Sun in the constellation of Centaurus.

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PSR B1620-26

PSR B1620-26 is a binary star system located at a distance of 3,800 parsecs (12,400 light-years) in the globular cluster of Messier 4 (M4, NGC 6121) in the constellation of Scorpius.

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A pulsar (from pulse and -ar as in quasar) is a highly magnetized rotating neutron star or white dwarf that emits a beam of electromagnetic radiation.

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R Aquarii

R Aquarii (R Aqr) is a variable star in the constellation Aquarius.

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Radial velocity

The radial velocity of an object with respect to a given point is the rate of change of the distance between the object and the point.

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Red dwarf

A red dwarf (or M dwarf) is a small and relatively cool star on the main sequence, of M spectral type.

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In physics, redshift happens when light or other electromagnetic radiation from an object is increased in wavelength, or shifted to the red end of the spectrum.

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Relativistic beaming

Relativistic beaming (also known as Doppler beaming, Doppler boosting, or the headlight effect) is the process by which relativistic effects modify the apparent luminosity of emitting matter that is moving at speeds close to the speed of light.

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Robert Grant Aitken

Robert Grant Aitken (December 31, 1864 – October 29, 1951) was an American astronomer.

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Roche lobe

The Roche lobe (or Roche limit) is the region around a star in a binary system within which orbiting material is gravitationally bound to that star.

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Rotational Brownian motion (astronomy)

In astronomy, rotational Brownian motion is the random walk in orientation of a binary star's orbital plane, induced by gravitational perturbations from passing stars.

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Science fiction

Science fiction (often shortened to Sci-Fi or SF) is a genre of speculative fiction, typically dealing with imaginative concepts such as advanced science and technology, spaceflight, time travel, and extraterrestrial life.

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Semi-major and semi-minor axes

In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the widest points of the perimeter.

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Sirius (a romanization of Greek Σείριος, Seirios,."glowing" or "scorching") is a star system and the brightest star in the Earth's night sky.

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Small Magellanic Cloud

The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way.

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SN 1572

SN 1572 (Tycho's Supernova, Tycho's Nova), or B Cassiopeiae (B Cas), was a supernova of Type Ia in the constellation Cassiopeia, one of about eight supernovae visible to the naked eye in historical records.

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Solar eclipse

A solar eclipse (as seen from the planet Earth) is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and when the Moon fully or partially blocks ("occults") the Sun.

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Spectral line

A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.

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A spectrometer is a scientific instrument used to separate and measure spectral components of a physical phenomenon.

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Spectroscopy is the study of the interaction between matter and electromagnetic radiation.

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A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.

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Star formation

Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars.

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Star system

A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction.

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Star Wars

Star Wars is an American epic space opera media franchise, centered on a film series created by George Lucas.

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Stellar atmosphere

The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone.

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Stellar black hole

A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a massive star.

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Stellar classification

In astronomy, stellar classification is the classification of stars based on their spectral characteristics.

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Stellar collision

A stellar collision is the coming together of two stars caused by gravity, gravitational radiation, or other mechanisms not well understood.

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Stellar evolution

Stellar evolution is the process by which a star changes over the course of time.

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Stellar kinematics

In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space.

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Stellar mass

Stellar mass is a phrase that is used by astronomers to describe the mass of a star.

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Stellar population

During 1944, Walter Baade categorized groups of stars within the Milky Way into bluer stars associated with the spiral arms and the general position of yellow stars near the central galactic bulge or within globular star clusters.

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Stellar wind

A stellar wind is a flow of gas ejected from the upper atmosphere of a star.

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A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as true giant stars.

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The Sun is the star at the center of the Solar System.

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A supernova (plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a star's life, either a massive star or a white dwarf, whose destruction is marked by one final, titanic explosion.

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Symbiotic binary

A symbiotic binary is a type of binary star system, often simply called a symbiotic star.

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Tatooine is a fictional desert planet that appears in the Star Wars space opera franchise.

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A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light).

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Three-body problem

In physics and classical mechanics, the three-body problem is the problem of taking an initial set of data that specifies the positions, masses, and velocities of three bodies for some particular point in time and then determining the motions of the three bodies, in accordance with Newton's laws of motion and of universal gravitation, which are the laws of classical mechanics.

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Tolman–Oppenheimer–Volkoff limit

The Tolman–Oppenheimer–Volkoff limit (or TOV limit) is an upper bound to the mass of cold, nonrotating neutron stars, analogous to the Chandrasekhar limit for white dwarf stars.

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Transit (astronomy)

In astronomy, a transit or astronomical transit is the phenomenon of at least one celestial body appearing to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point.

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Triangulum Galaxy

The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years (ly) from Earth in the constellation Triangulum.

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Trigonometric functions

In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are functions of an angle.

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Two-body problem in general relativity

The two-body problem (or Kepler problem) in general relativity is the determination of the motion and gravitational field of two bodies as described by the field equations of general relativity.

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Tycho Brahe

Tycho Brahe (born Tyge Ottesen Brahe;. He adopted the Latinized form "Tycho Brahe" (sometimes written Tÿcho) at around age fifteen. The name Tycho comes from Tyche (Τύχη, meaning "luck" in Greek, Roman equivalent: Fortuna), a tutelary deity of fortune and prosperity of ancient Greek city cults. He is now generally referred to as "Tycho," as was common in Scandinavia in his time, rather than by his surname "Brahe" (a spurious appellative form of his name, Tycho de Brahe, only appears much later). 14 December 154624 October 1601) was a Danish nobleman, astronomer, and writer known for his accurate and comprehensive astronomical and planetary observations.

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Type Ia supernova

A type Ia supernova (read "type one-a") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf.

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United States Naval Observatory

The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation and Timing (PNT) for the United States Navy and the United States Department of Defense.

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Ursa Major

Ursa Major (also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory.

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Variable star

A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.

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Visual binary

A visual binary is a gravitationally bound system that can be resolved into two stars.

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W Ursae Majoris

W Ursae Majoris (W UMa) is the variable star designation for a binary star system in the northern constellation of Ursa Major.

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Washington Double Star Catalog

The Washington Double Star Catalog, or WDS, is a catalog of double stars, maintained at the United States Naval Observatory.

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White dwarf

A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter.

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William Herschel

Frederick William Herschel, (Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer, composer and brother of fellow astronomer Caroline Herschel, with whom he worked.

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Wolf–Rayet star

Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of highly ionised helium and nitrogen or carbon.

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Wolfram Demonstrations Project

The Wolfram Demonstrations Project is an organized, open-source collection of small (or medium-size) interactive programs called Demonstrations, which are meant to visually and interactively represent ideas from a range of fields.

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X-rays make up X-radiation, a form of electromagnetic radiation.

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X-ray binary

X-ray binaries are a class of binary stars that are luminous in X-rays.

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Xi Ursae Majoris

Xi Ursae Majoris (ξ Ursae Majoris, abbreviated Xi UMa, ξ UMa), also named Alula Australis, is a star system in the constellation of Ursa Major.

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Zeta Reticuli

Zeta Reticuli (Zeta Ret, ζ Reticuli, ζ Ret) is a wide binary star system in the southern constellation of Reticulum.

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Zeta Ursae Majoris

Mizar is a 2nd magnitude star in the handle of the Big Dipper asterism in the constellation of Ursa Major.

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104 Aquarii

104 Aquarii (abbreviated 104 Aqr) is a star in the equatorial constellation of Aquarius.

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107 Aquarii

107 Aquarii (abbreviated 107 Aqr) is a double star in the equatorial constellation of Aquarius.

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61 Cygni

61 Cygni Not to be confused with 16 Cygni, a more distant system containing two G-type stars harboring the gas giant planet 16 Cygni Bb.

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AR Lacertae variable, Astrometric binaries, Astrometric binary, Astrometric companion, Binary (astronomy), Binary Star, Binary Stars, Binary star formation, Binary star system, Binary star system formation, Binary stars, Binary-star system, Close binary, Companion star, Detached binaries, Detached binary, Double Stars, Double star system, Double sun, Double-lined binary, Double-lined spectroscopic binary, Eclipsing Variable Star, Eclipsing binaries, Eclipsing binary, Eclipsing binary star, Eclipsing variable, Eclipsing variable star, Eclipsing variable stars, Hot companion, Invisible companion, Photometric binary, Physical double star, Proper motion companion, S type orbit, Semidetached binaries, Semidetached binary, Spectroscopic binaries, Spectroscopic binary, Telescopic binary, Twin star system, Twin stars, Visual binaries.


[1] https://en.wikipedia.org/wiki/Binary_star

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