131 relations: Absolute magnitude, Accuracy and precision, Alex Filippenko, Andromeda Galaxy, Apparent magnitude, Asteroid, Astrometry, Astronomical spectroscopy, Astronomical unit, Astronomy, Astronomy & Astrophysics, Baryon acoustic oscillations, Binary star, Black hole, Bolometer, Calibration, Centre for Astrophysics and Supercomputing, Cepheid variable, Chandrasekhar limit, Charge-coupled device, Chirp mass, Dark energy, Distance, Distance measures (cosmology), Distance modulus, Doppler effect, Dynamical parallax, Earth, Eddington luminosity, Edwin Hubble, Elliptical galaxy, Error, Extinction (astronomy), Faber–Jackson relation, Fraunhofer lines, Friedmann equations, Gaia (spacecraft), Galaxy cluster, Globular cluster, Gravitational lens, Gravitational wave, Hertzsprung–Russell diagram, Hipparcos, Hubble's law, Hyades (star cluster), Interferometry, Inverse-square law, Jay Pasachoff, Kepler's laws of planetary motion, Kilonova, ..., Large Magellanic Cloud, Light curve, Light echo, Light-year, LIGO Scientific Collaboration, Luminosity, Main sequence, Metallicity, Milky Way, Minute and second of arc, Monthly Notices of the Royal Astronomical Society, NASA, Nature (journal), Nebula, Neutron star, Nova, Olin Chaddock Wilson, Open cluster, Orbital decay, Parallax, Parsec, Photosphere, Physical cosmology, Planetary nebula, Planetary nebula luminosity function, Propagation of uncertainty, Proper motion, Proportionality (mathematics), Publications of the Astronomical Society of the Pacific, Quasar, Radar, Radial velocity, Ratio, Redshift, René Racine, RR Lyrae variable, Sigma-D relation, Small Magellanic Cloud, SN 2003fg, Solar System, Spacecraft, Spectroscopic parallax, Spiral galaxy, Square root, Standard ruler, Star, Star cluster, Star formation, Statistics, Stellar classification, Stellar evolution, Stellar parallax, Stellar population, Sun, Supernova, Supernova remnant, Surface brightness, Surface brightness fluctuation, The Astronomical Journal, The Astrophysical Journal, Tip of the red-giant branch, Triangle, Triangulum Galaxy, Tully–Fisher relation, Type Ia supernova, Universe, Vainu Bappu, Variable star, Velocity, Velocity dispersion, Venus, Virgo Cluster, Virgo interferometer, Visual binary, Void (astronomy), Walter Baade, Wide Field Camera 3, WiggleZ Dark Energy Survey, Wilson–Bappu effect, X-ray binary, X-ray burster. Expand index (81 more) » « Shrink index
Absolute magnitude is a measure of the luminosity of a celestial object, on a logarithmic astronomical magnitude scale.
Precision is a description of random errors, a measure of statistical variability.
Alexei Vladimir "Alex" Filippenko (born July 25, 1958) is an American astrophysicist and professor of astronomy at the University of California, Berkeley.
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.
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
Asteroids are minor planets, especially those of the inner Solar System.
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies.
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light and radio, which radiates from stars and other celestial objects.
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
Astronomy & Astrophysics is a peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics.
In cosmology, baryon acoustic oscillations (BAO) are regular, periodic fluctuations in the density of the visible baryonic matter (normal matter) of the universe.
A binary star is a star system consisting of two stars orbiting around their common barycenter.
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.
A bolometer is a device for measuring the power of incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance.
Calibration in measurement technology and metrology is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy.
The Centre for Astrophysics and Supercomputing (CAS) is a research centre located at the Swinburne University in Melbourne, Australia.
A Cepheid variable is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude.
The Chandrasekhar limit is the maximum mass of a stable white dwarf star.
A charge-coupled device (CCD) is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value.
The chirp mass of a compact binary star system with component masses m_1 and m_2 is given by \mathcal.
In physical cosmology and astronomy, dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe.
Distance is a numerical measurement of how far apart objects are.
Distance measures are used in physical cosmology to give a natural notion of the distance between two objects or events in the universe.
The distance modulus is a way of expressing distances that is often used in astronomy.
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.
In astronomy, the distance to a visual binary star may be estimated from the masses of its two components, the size of their orbit, and the period of their orbit about one another.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
The Eddington luminosity, also referred to as the Eddington limit, is the maximum luminosity a body (such as a star) can achieve when there is balance between the force of radiation acting outward and the gravitational force acting inward.
Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer.
An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless image.
An error (from the Latin error, meaning "wandering") is an action which is inaccurate or incorrect.
In astronomy, extinction is the absorption and scattering of electromagnetic radiation by dust and gas between an emitting astronomical object and the observer.
The Faber–Jackson relation provided the first empirical power-law relation between the luminosity L and the central stellar velocity dispersion \sigma of early-type galaxies, and was presented by the astronomers Sandra M. Faber and Robert Earl Jackson in 1976.
In physics and optics, the Fraunhofer lines are a set of spectral lines named after the German physicist Joseph von Fraunhofer (1787–1826).
The Friedmann equations are a set of equations in physical cosmology that govern the expansion of space in homogeneous and isotropic models of the universe within the context of general relativity.
Gaia is a space observatory of the European Space Agency (ESA) designed for astrometry: measuring the positions and distances of stars with unprecedented precision.
A galaxy cluster, or cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity with typical masses ranging from 1014–1015 solar masses.
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite.
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.
Gravitational waves are the disturbance in the fabric ("curvature") of spacetime generated by accelerated masses and propagate as waves outward from their source at the speed of light.
The Hertzsprung–Russell diagram, abbreviated H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
Hipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993.
Hubble's law is the name for the observation in physical cosmology that.
The Hyades (Greek Ὑάδες, also known as Melotte 25 or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.
Interferometry is a family of techniques in which waves, usually electromagnetic waves, are superimposed causing the phenomenon of interference in order to extract information.
The inverse-square law, in physics, is any physical law stating that a specified physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity.
Jay Myron Pasachoff (born 1943) is an American astronomer.
In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.
A kilonova (macronova or r-process supernova) is a transient astronomical event that occurs in a compact binary system when two neutron stars or a neutron star and a black hole merge into each other.
The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way.
In astronomy, a light curve is a graph of light intensity of a celestial object or region, as a function of time.
Reflected light following path B arrives shortly after the direct flash following path A but before light following path C. B and C have the same apparent distance from the star as seen from Earth. A light echo is a physical phenomenon caused by light reflected off surfaces distant from the source, and arriving at the observer with a delay relative to this distance.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
The LIGO Scientific Collaboration (LSC) is a scientific collaboration of international physics institutes and research groups dedicated to the search for gravitational waves.
In astronomy, luminosity is the total amount of energy emitted per unit of time by a star, galaxy, or other astronomical object.
In astronomy, the main sequence is a continuous and distinctive band of stars that appear on plots of stellar color versus brightness.
In astronomy, metallicity is used to describe the abundance of elements present in an object that are heavier than hydrogen or helium.
The Milky Way is the galaxy that contains our Solar System.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
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.
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.
A nebula (Latin for "cloud" or "fog"; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases.
A neutron star is the collapsed core of a large star which before collapse had a total of between 10 and 29 solar masses.
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.
Olin Chaddock Wilson (January 13, 1909 – July 13, 1994) was an American astronomer best known for his work as a stellar spectroscopist.
An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age.
In orbital mechanics, decay is a process that leads to gradual decrease of the distance between two orbiting bodies at their closest approach (the periapsis) over many orbital periods.
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.
The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
The photosphere is a star's outer shell from which light is radiated.
Physical cosmology is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its origin, structure, evolution, and ultimate fate.
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.
Planetary nebula luminosity function (PNLF) is a secondary distance indicator used in astronomy.
In statistics, propagation of uncertainty (or propagation of error) is the effect of variables' uncertainties (or errors, more specifically random errors) on the uncertainty of a function based on them.
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.
In mathematics, two variables are proportional if there is always a constant ratio between them.
Publications of the Astronomical Society of the Pacific (often abbreviated as PASP in references and literature) is a monthly peer-reviewed scientific journal managed by the Astronomical Society of the Pacific.
A quasar (also known as a QSO or quasi-stellar object) is an extremely luminous active galactic nucleus (AGN).
Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects.
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.
In mathematics, a ratio is a relationship between two numbers indicating how many times the first number contains the second.
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.
René Racine (born 1939) is a Québécois Canadian professor and astronomer who specializes in the study of globular clusters.
RR Lyrae variables are periodic variable stars, commonly found in globular clusters.
The Sigma-D relation, or Σ-D Relation, is the radio surface brightness to diameter relation of a supernova remnant.
The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way.
SN 2003fg, sometimes called the "Champagne Supernova", was an unusual Type Ia supernova.
The Solar SystemCapitalization of the name varies.
A spacecraft is a vehicle or machine designed to fly in outer space.
Spectroscopic parallax is an astronomical method for measuring the distances to stars.
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae(pp. 124–151) and, as such, form part of the Hubble sequence.
In mathematics, a square root of a number a is a number y such that; in other words, a number y whose square (the result of multiplying the number by itself, or) is a. For example, 4 and −4 are square roots of 16 because.
A standard ruler is an astronomical object for which the actual physical size is known.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
Star clusters are groups of stars.
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.
Statistics is a branch of mathematics dealing with the collection, analysis, interpretation, presentation, and organization of data.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
Stellar evolution is the process by which a star changes over the course of time.
Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects.
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.
The Sun is the star at the center of the Solar System.
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.
A supernova remnant (SNR) is the structure resulting from the explosion of a star in a supernova.
In astronomy, surface brightness quantifies the apparent brightness or flux density per unit angular area of a spatially extended object such as a galaxy or nebula, or of the night sky background.
Surface brightness fluctuation (SBF) is a secondary distance indicator used to estimate distances to galaxies.
The Astronomical Journal (often abbreviated AJ in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society and currently published by IOP Publishing.
The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.
Tip of the red-giant branch (TRGB) is a primary distance indicator used in astronomy.
A triangle is a polygon with three edges and three vertices.
The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years (ly) from Earth in the constellation Triangulum.
lenticular galaxies In astronomy, the Tully–Fisher relation (TFR) is an empirical relationship between the mass or intrinsic luminosity of a spiral galaxy and its angular velocity or emission line width.
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.
The Universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy.
Manali Kallat Vainu Bappu (August 10, 1927 – August 19, 1982) was an Indian astronomer and president of the International Astronomical Union.
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.
The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time.
In astronomy, the velocity dispersion (σ) is the statistical dispersion of velocities about the mean velocity for a group of objects, such as an open cluster, globular cluster, galaxy, galaxy cluster, or supercluster.
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days.
The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo.
The Virgo interferometer is a large interferometer designed to detect gravitational waves predicted by the general theory of relativity.
A visual binary is a gravitationally bound system that can be resolved into two stars.
Cosmic voids are vast spaces between filaments (the largest-scale structures in the universe), which contain very few or no galaxies.
Wilhelm Heinrich Walter Baade (March 24, 1893 – June 25, 1960) was a German astronomer who worked in the United States from 1931 to 1959.
The Wide Field Camera 3 (WFC3) is the Hubble Space Telescope's last and most technologically advanced instrument to take images in the visible spectrum.
The WiggleZ Dark Energy Survey was a large-scale astronomical redshift survey carried out on the 3.9 metre Anglo-Australian Telescope (AAT) at the Siding Spring Observatory, New South Wales between August 2006 and January 2011.
The Ca II K line in cool stars is among the strongest emission lines which originates in the star's chromosphere.
X-ray binaries are a class of binary stars that are luminous in X-rays.
X-ray bursters are one class of X-ray binary stars exhibiting periodic and rapid increases in luminosity (typically a factor of 10 or greater) that peak in the X-ray regime of the electromagnetic spectrum.
Astronomical scale, Astronomical scales, Cosmic Distance Ladder, Cosmological distance scale, Cosmological ladder, Distance (astronomy), Distance ladder, Extragalactic Distance Scale, Extragalactic distance scale, Main sequence fitting, Standard Candle, Standard candle, Standard candles, Standard siren, Stellar distance.