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Variable Stars
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: * ''Intrinsic variables'', whose luminosity actually changes periodically; for example, because the star swells and shrinks. * ''Extrinsic variables'', whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star Eclipsing binaries, has an orbiting companion that sometimes eclipses it. Many, possibly most, stars exhibit at least some oscillation in luminosity: the energy output of the Sun, for example, varies by about 0.1% over an 11-year solar cycle. Discovery An ancient Egyptian calendar of lucky and unlucky days composed some 3,200 years ago may be the oldest preserved historical document of the discovery of a variable star, the eclipsin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eso2003c
The European Southern Observatory is an astronomical research organisation. ESO may also refer to: *Employee stock option (also: executive stock option) *''Ether Saga Odyssey'', a fantasy massively multiplayer online role-playing game *''The Elder Scrolls Online'', a fantasy massively multiplayer online role-playing game *Existential second-order logic *ESO (motorcycles) *Eso (town), Orhionmwon, Edo State, Nigeria Organisations * European Standardisation Organisations: European_Committee_for_Standardization, CEN (European Committee for Standardization), CENELEC (European Committee for Electrotechnical Standardisation) and ETSI (European Telecommunications Standards Institute) *Ensemble Studios Online *Edmonton Symphony Orchestra *Energijos skirstymo operatorius (ESO), Lithuanian electricity transmission network operator *Evergreen Symphony Orchestra, an orchestra in Taiwan *Eteläsuomalainen osakunta, a student nation at the University of Helsinki *Libyan External Security Organi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Goodricke
John Goodricke FRS (17 September 1764 – 20 April 1786) was an English amateur astronomer. He is best known for his observations of the variable star Algol (Beta Persei) in 1782. Life and work John Goodricke, named after his great-grandfather Sir John Goodricke 1617–1670 (see Goodricke baronets of Ribston Hall), was born in Groningen in the Netherlands, but lived most of his life in England. He became deaf in early childhood due to a severe illness. His parents sent him to Thomas Braidwood's Academy, a school for deaf pupils in Edinburgh, and in 1778 to the Warrington Academy. After leaving Warrington, Goodricke returned to live with his parents in York. There, he became friends with his neighbour Edward Pigott, whose father Nathaniel Pigott had built a sophisticated private observatory. Edward was already interested in variable stars, and he gave Goodricke a list of those that he thought were worthy of observation. Goodricke is credited with discovering the peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photometry (astronomy)
In astronomy, photometry, from Greek '' photo-'' ("light") and '' -metry'' ("measure"), is a technique used in astronomy that is concerned with measuring the flux or intensity of light radiated by astronomical objects. This light is measured through a telescope using a photometer, often made using electronic devices such as a CCD photometer or a photoelectric photometer that converts light into an electric current by the photoelectric effect. When calibrated against standard stars (or other light sources) of known intensity and colour, photometers can measure the brightness or apparent magnitude of celestial objects. The methods used to perform photometry depend on the wavelength region under study. At its most basic, photometry is conducted by gathering light and passing it through specialized photometric optical bandpass filters, and then capturing and recording the light energy with a photosensitive instrument. Standard sets of passbands (called a photometric system) are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New View Of The Great Nebula In Carina
New or NEW may refer to: Music * New, singer of K-pop group The Boyz * ''New'' (album), by Paul McCartney, 2013 ** "New" (Paul McCartney song), 2013 * ''New'' (EP), by Regurgitator, 1995 * "New" (Daya song), 2017 * "New" (No Doubt song), 1999 * "new", a song by Loona from the 2017 single album '' Yves'' * "The New", a song by Interpol from the 2002 album ''Turn On the Bright Lights'' Transportation * Lakefront Airport, New Orleans, U.S., IATA airport code NEW * Newcraighall railway station, Scotland, station code NEW Other uses * ''New'' (film), a 2004 Tamil movie * New (surname), an English family name * NEW (TV station), in Australia * new and delete (C++), in the computer programming language * Net economic welfare, a proposed macroeconomic indicator * Net explosive weight, also known as net explosive quantity * Network of enlightened Women, an American organization * Newar language, ISO 639-2/3 language code new * Next Entertainment World, a South Korean media co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Curve
In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis and with time on the ''x''-axis. The light is usually in a particular frequency interval or frequency band, band. Light curves can be periodic, as in the case of eclipsing binary, eclipsing binaries, Cepheid variables, other periodic variables, and Methods of detecting extrasolar planets#Transit photometry, transiting extrasolar planets; or aperiodic, like the light curve of a nova, cataclysmic variable star, supernova, gravitational microlensing, microlensing event, or binary as observed during occultation events. The study of a light curve and other observations can yield considerable information about the physical process that produces such a light curve, or constrain the physical theories about it. Variable stars Graphs of the ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Spectrum
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and other celestial objects. A stellar spectrum can reveal many properties of stars, such as their chemical composition, temperature, density, mass, distance and luminosity. Spectroscopy can show the velocity of motion towards or away from the observer by measuring the Doppler shift. Spectroscopy is also used to study the physical properties of many other types of celestial objects such as planets, nebulae, galaxies, and active galactic nuclei. Background Astronomical spectroscopy is used to measure three major bands of radiation in the electromagnetic spectrum: visible light, radio waves, and X-rays. While all spectroscopy looks at specific bands of the spectrum, different methods are required to acquire the signal depending on the freque ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Catalogue Of Variable Stars
The General Catalogue of Variable Stars (GCVS) is a list of variable stars in the Milky Way Galaxy. Its first edition, containing 10,820 stars, was published in 1948 by the Academy of Sciences of the USSR, edited by and Pavel Parenago. Second and third editions were published in 1958 and 1968. The fourth edition, containing 28,435 stars, was published in three volumes in 1985–1987. Later, two more volumes were published: the fourth volume containing reference tables and the fifth volume containing extragalactic variable stars. The first release of the fifth edition (GCVS 5.1), which is periodically updated, currently contains 58,035 variable stars; it is available at the GCVS website and at the VizieR A vizier (; ; ) is a high-ranking political advisor or Minister (government), minister in the Near East. The Abbasids, Abbasid caliphs gave the title ''wazir'' to a minister formerly called ''katib'' (secretary), who was at first merely a help ... astronomical catalogue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cepheid Variable
A Cepheid variable () is a type of variable star that pulsates radially, varying in both diameter and temperature. It changes in brightness, with a well-defined stable period (typically 1–100 days) and amplitude. Cepheids are important cosmic benchmarks for scaling galactic and extragalactic distances; a strong direct relationship exists between a Cepheid variable's luminosity and its pulsation period. This characteristic of classical Cepheids was discovered in 1908 by Henrietta Swan Leavitt after studying thousands of variable stars in the Magellanic Clouds. The discovery establishes the ''true luminosity'' of a Cepheid by observing its pulsation period. This in turn gives the distance to the star by comparing its known luminosity to its observed brightness, calibrated by directly observing the parallax distance to the closest Cepheids such as RS Puppis and Polaris. Cepheids change brightness due to the κ–mechanism, which occurs when opacity in a star increases wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cecilia Payne-Gaposchkin
Cecilia Payne-Gaposchkin (born Cecilia Helena Payne; – ) was a British-born American astronomer and astrophysicist. Her work on the cosmic makeup of the universe and the nature of variable stars was foundational to modern astrophysics. She determined that stars were composed primarily of hydrogen and helium in her 1925 doctoral thesis. Her groundbreaking conclusion was initially rejected by leading astrophysicists, including Henry Norris Russell, because it contradicted the science of the time, which held that no significant elemental differences distinguished the Sun and Earth. Independent observations eventually proved that she was correct. Despite completing her studies, because she was a woman Payne was not eligible to receive a degree from the University of Cambridge. Similarly in America, she was not eligible to receive a doctoral degree (PhD) for her studies at Harvard University, as they did not grant doctoral degrees to women at the time, instead, she received he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Lyrae
Beta Lyrae (β Lyrae, abbreviated Beta Lyr, β Lyr) officially named Sheliak (Arabic: الشلياق, Romanization: ash-Shiliyāq) ( IPA: ), the traditional name of the system, is a multiple star system in the constellation of Lyra. Based on stellar parallax, parallax measurements obtained during the Hipparcos mission, it is approximately distant from the Sun. Although it appears as a single point of light to the naked eye, it actually consists of six components of apparent magnitude 14.3 or brighter. The brightest component, designated Beta Lyrae A, is itself a triple star system, consisting of an binary star#Eclipsing binaries, eclipsing binary pair (Aa) and a single star (Ab). The binary pair's two components are designated Beta Lyrae Aa1 and Aa2. The additional five components, designated Beta Lyrae B, C, D, E, and F, are currently considered to be single stars. Nomenclature ''β Lyrae'' (Latinisation of names, Latinised to ''Beta Lyrae'') is the system's Bayer des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
