138 relations: Accretion (astrophysics), Age of the universe, Aldebaran, Alpha process, Angular momentum, Arcturus, Astrophysical maser, Astrophysics, Asymptotic giant branch, Binary system, Black dwarf, Black hole, Blue supergiant star, Boötes, Brown dwarf, Carbon, Carbon star, Carbon-burning process, Centrifugal force, Chandrasekhar limit, Circumstellar dust, Circumstellar envelope, CNO cycle, Computer simulation, Convection, Degenerate matter, Deuterium, Deuterium fusion, Dredge-up, Electron, Electron capture, Electron degeneracy pressure, Energy, Escape velocity, G-type main-sequence star, Galaxy formation and evolution, General relativity, Giant star, Gravitational binding energy, Gravitational collapse, Gravitational energy, Gravitational potential, Gravity, Helium, Helium flash, Hertzsprung–Russell diagram, Horizontal branch, Hydrogen, Hydrogen atom, Hydrostatic equilibrium, ..., Infrared, Instability strip, International Astronomical Union, Iron, Iron-56, Isotope, Jupiter mass, Kelvin, Kinetic energy, Luminosity, Luminous blue variable, Magnesium, Main sequence, Maser, Mathematical model, Metallicity, Milky Way, Mira variable, Molecular cloud, Nebula, Neon, Neon-burning process, Neutrino, Neutron, Neutron star, Nova, Nuclear fusion, Nuclear reaction, Nucleon, Nucleosynthesis, O-type main-sequence star, OH/IR star, Ohio State University, Oxygen, Oxygen-burning process, Pair-instability supernova, Pauli exclusion principle, Photodisintegration, Planet, Planetary nebula, Pre-main-sequence star, Pressure, Proton–proton chain reaction, Protostar, Pulsar, Quantum mechanics, R Coronae Borealis variable, Red clump, Red dwarf, Red giant, Red supergiant star, Red-giant branch, RR Lyrae variable, Schönberg–Chandrasekhar limit, Schwarzschild radius, Shock wave, Silicon, SN 1987A, Solar System, Spectroscopy, Standard solar model, Star, Star cluster, Stellar classification, Stellar nucleosynthesis, Stellar population, Stellar structure, Subdwarf B star, Subgiant, Sulfur, Sun, Supergiant star, Supernova, Taurus (constellation), Temperature, Timeline of stellar astronomy, Tip of the red-giant branch, Tolman–Oppenheimer–Volkoff limit, Triple-alpha process, Type Ia supernova, Type II supernova, Universe, University of Maryland, College Park, Uranium, White dwarf, Wide-field Infrared Survey Explorer, Wolf–Rayet star, Yellow hypergiant. Expand index (88 more) » « Shrink index
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk.
In physical cosmology, the age of the universe is the time elapsed since the Big Bang.
Aldebaran, designated Alpha Tauri (α Tauri, abbreviated Alpha Tau, α Tau), is an orange giant star located about 65 light-years from the Sun in the zodiac constellation of Taurus.
The alpha process, also known as the alpha ladder, is one of two classes of nuclear fusion reactions by which stars convert helium into heavier elements, the other being the triple-alpha process.
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum.
An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum.
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".
The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars.
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).
A black dwarf is a theoretical stellar remnant, specifically a white dwarf that has cooled sufficiently that it no longer emits significant heat or light.
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.
Blue supergiant stars are hot luminous stars, referred to scientifically as OB supergiants.
Boötes is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere.
Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, having masses between approximately 13 to 75–80 times that of Jupiter, or approximately to about.
Carbon (from carbo "coal") is a chemical element with symbol C and atomic number 6.
A carbon star is typically an asymptotic giant branch star, a luminous red giant, whose atmosphere contains more carbon than oxygen; the two elements combine in the upper layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere, leaving carbon atoms free to form other carbon compounds, giving the star a "sooty" atmosphere and a strikingly ruby red appearance.
The carbon-burning process or carbon fusion is a set of nuclear fusion reactions that take place in the cores of massive stars (at least 8 \beginsmallmatrixM_\odot\endsmallmatrix at birth) that combines carbon into other elements.
In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) directed away from the axis of rotation that appears to act on all objects when viewed in a rotating frame of reference.
The Chandrasekhar limit is the maximum mass of a stable white dwarf star.
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
Circumstellar dust is cosmic dust around a star.
A circumstellar envelope (CSE) is a part of a star that has a roughly spherical shape and is not gravitationally bound to the star core.
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.
Computer simulation is the reproduction of the behavior of a system using a computer to simulate the outcomes of a mathematical model associated with said system.
Convection is the heat transfer due to bulk movement of molecules within fluids such as gases and liquids, including molten rock (rheid).
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.
Deuterium (or hydrogen-2, symbol or, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1).
Deuterium fusion, also called deuterium burning, is a nuclear fusion reaction that occurs in stars and some substellar objects, in which a deuterium nucleus and a proton combine to form a helium-3 nucleus.
A dredge-up is a period in the evolution of a star where a surface convection zone extends down to the layers where material has undergone nuclear fusion.
The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.
Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shell.
Electron degeneracy pressure is a particular manifestation of the more general phenomenon of quantum degeneracy pressure.
In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object.
In physics, escape velocity is the minimum speed needed for an object to escape from the gravitational influence of a massive body.
A G-type main-sequence star (Spectral type: G-V), often (and imprecisely) called a yellow dwarf, or G dwarf star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.84 to 1.15 solar masses and surface temperature of between 5,300 and 6,000 K., G. M. H. J. Habets and J. R. W. Heintze, Astronomy and Astrophysics Supplement 46 (November 1981), pp.
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies.
General relativity (GR, also known as the general theory of relativity or GTR) is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics.
A giant star is a star with substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature.
A gravitational binding energy is the minimum energy that must be added to a system for the system to cease being in a gravitationally bound state.
Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the center of gravity.
Gravitational energy is the potential energy a body with mass has in relation to another massive object due to gravity.
In classical mechanics, the gravitational potential at a location is equal to the work (energy transferred) per unit mass that would be needed to move the object from a fixed reference location to the location of the object.
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.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
A helium flash is a very brief thermal runaway nuclear fusion of large quantities of helium into carbon through the triple-alpha process in the core of low mass stars (between 0.8 solar masses and 2.0) during their red giant phase (the Sun is predicted to experience a flash 1.2 billion years after it leaves the main sequence).
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.
The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red giant branch in stars whose masses are similar to the Sun's.
Hydrogen is a chemical element with symbol H and atomic number 1.
A hydrogen atom is an atom of the chemical element hydrogen.
In fluid mechanics, a fluid is said to be in hydrostatic equilibrium or hydrostatic balance when it is at rest, or when the flow velocity at each point is constant over time.
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions). It is sometimes called infrared light.
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 supergiants.
The International Astronomical Union (IAU; Union astronomique internationale, UAI) is an international association of professional astronomers, at the PhD level and beyond, active in professional research and education in astronomy.
Iron is a chemical element with symbol Fe (from ferrum) and atomic number 26.
Iron-56 (56Fe) is the most common isotope of iron.
Isotopes are variants of a particular chemical element which differ in neutron number.
Jupiter mass, also called Jovian mass is the unit of mass equal to the total mass of the planet Jupiter.
The Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
In astronomy, luminosity is the total amount of energy emitted per unit of time by a star, galaxy, or other astronomical object.
Luminous blue variables (LBVs) are massive evolved stars that show unpredictable and sometimes dramatic variations in both their spectra and brightness.
Magnesium is a chemical element with symbol Mg and atomic number 12.
In astronomy, the main sequence is a continuous and distinctive band of stars that appear on plots of stellar color versus brightness.
A maser (an acronym for "microwave amplification by stimulated emission of radiation") is a device that produces coherent electromagnetic waves through amplification by stimulated emission.
A mathematical model is a description of a system using mathematical concepts and language.
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.
Mira variables ("Mira", Latin, adj. - feminine form of adjective "wonderful"), named for the prototype star Mira, are a class of pulsating variable stars characterized by very red colours, pulsation periods longer than 100 days, and amplitudes greater than one magnitude in infrared and 2.5 magnitude at visual wavelengths.
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).
A nebula (Latin for "cloud" or "fog"; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases.
Neon is a chemical element with symbol Ne and atomic number 10.
The neon-burning process (nuclear decay) is a set of nuclear fusion reactions that take place in massive stars (at least 8 Solar masses).
A neutrino (denoted by the Greek letter ν) is a fermion (an elementary particle with half-integer spin) that interacts only via the weak subatomic force and gravity.
A neutron star is the collapsed core of a large star which before collapse had a total of between 10 and 29 solar masses.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
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.
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).
In nuclear physics and nuclear chemistry, a nuclear reaction is semantically considered to be the process in which two nuclei, or else a nucleus of an atom and a subatomic particle (such as a proton, neutron, or high energy electron) from outside the atom, collide to produce one or more nuclides that are different from the nuclide(s) that began the process.
In chemistry and physics, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus.
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons.
An O-type main-sequence star (O V) is a main-sequence (core hydrogen-burning) star of spectral type O and luminosity class V. These stars have between 15 and 90 times the mass of the Sun and surface temperatures between 30,000 and 50,000 K. They are between 40,000 and 1,000,000 times as luminous as the Sun.
An OH/IR star is an asymptotic giant branch (AGB) star that shows strong OH maser emission and is unusually bright at near-infrared wavelengths.
The Ohio State University, commonly referred to as Ohio State or OSU, is a large, primarily residential, public university in Columbus, Ohio.
Oxygen is a chemical element with symbol O and atomic number 8.
The oxygen-burning process is a set of nuclear fusion reactions that take place in massive stars that have used up the lighter elements in their cores.
A pair-instability supernova occurs when pair production, the production of free electrons and positrons in the collision between atomic nuclei and energetic gamma rays, temporarily reduces the internal pressure supporting a supermassive star's core against gravitational collapse.
The Pauli exclusion principle is the quantum mechanical principle which states that two or more identical fermions (particles with half-integer spin) cannot occupy the same quantum state within a quantum system simultaneously.
Photodisintegration (also called phototransmutation) is a nuclear process in which an atomic nucleus absorbs a high-energy gamma ray, enters an excited state, and immediately decays by emitting a subatomic particle.
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.
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.
A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence.
Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
The proton–proton chain reaction is one of the two (known) sets of fusion reactions by which stars convert hydrogen to helium.
A protostar is a very young star that is still gathering mass from its parent molecular cloud.
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.
Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
An R Coronae Borealis variable (abbreviated RCB, R CrB) is an eruptive variable star that varies in luminosity in two modes, one low amplitude pulsation (a few tenths of a magnitude), and one irregular, unpredictably-sudden fading by 1 to 9 magnitudes.
The red clump is a clustering of red giants in the Hertzsprung–Russell diagram at around 5,000 K and absolute magnitude (MV) +0.5, slightly hotter than most red-giant-branch stars of the same luminosity.
A red dwarf (or M dwarf) is a small and relatively cool star on the main sequence, of M spectral type.
A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses) in a late phase of stellar evolution.
Red supergiants are stars with a supergiant luminosity class (Yerkes class I) of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous.
The red-giant branch (RGB), sometimes called the first giant branch, is the portion of the giant branch before helium ignition occurs in the course of stellar evolution.
RR Lyrae variables are periodic variable stars, commonly found in globular clusters.
In stellar astrophysics, the Schönberg–Chandrasekhar limit is the maximum mass of a non-fusing, isothermal core that can support an enclosing envelope.
The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is a physical parameter that shows up in the Schwarzschild solution to Einstein's field equations, corresponding to the radius defining the event horizon of a Schwarzschild black hole.
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance.
Silicon is a chemical element with symbol Si and atomic number 14.
SN 1987A was a peculiar type II supernova in the Large Magellanic Cloud, a dwarf galaxy satellite of the Milky Way.
The Solar SystemCapitalization of the name varies.
Spectroscopy is the study of the interaction between matter and electromagnetic radiation.
The standard solar model (SSM) is a mathematical treatment of the Sun as a spherical ball of gas (in varying states of ionisation, with the hydrogen in the deep interior being a completely ionised plasma).
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.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
Stellar nucleosynthesis is the theory explaining the creation (nucleosynthesis) of chemical elements by nuclear fusion reactions between atoms within the stars.
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.
Stars of different mass and age have varying internal structures.
A B-type subdwarf (sdB) is a kind of subdwarf star with spectral type B. They differ from the typical subdwarf by being much hotter and brighter.
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.
Sulfur or sulphur is a chemical element with symbol S and atomic number 16.
The Sun is the star at the center of the Solar System.
Supergiants are among the most massive and most luminous stars.
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.
Taurus (Latin for "the Bull") is one of the constellations of the zodiac, which means it is crossed by the plane of the ecliptic.
Temperature is a physical quantity expressing hot and cold.
Timeline of stellar astronomy.
Tip of the red-giant branch (TRGB) is a primary distance indicator used in astronomy.
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.
The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.
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.
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star.
The Universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy.
The University of Maryland, College Park (commonly referred to as the University of Maryland, UMD, or simply Maryland) is a public research university located in the city of College Park in Prince George's County, Maryland, approximately from the northeast border of Washington, D.C. Founded in 1856, the university is the flagship institution of the University System of Maryland.
Uranium is a chemical element with symbol U and atomic number 92.
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter.
Wide-field Infrared Survey Explorer (WISE) is a NASA infrared-wavelength astronomical space telescope launched in December 2009, and placed in hibernation in February 2011.
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.
A yellow hypergiant is a massive star with an extended atmosphere, a spectral class from A to K, and an initial mass of about 20–60 solar masses but having lost as much as half that mass.
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.
Cycle of stars, Evolution of stars, Life cycle of a star, Life cycle of stars, Life of a star, Star Death, Star cycle, Star evolution, Star life cycle, Star lifecycle, Stellar Evolution, Stellar death, Stellar evolutionary model, Stellar life, Stellar life cycle, The life of a star.