AF Andromedae
   HOME
*





AF Andromedae
AF Andromedae (AF And) is a luminous blue variable (LBV), a type of variable star. The star is one of the most luminous variables in M31, the Andromeda Galaxy. Discovery The star was discovered to be variable in 1927, with a photographic magnitude range of 15.3 to 16.5, at the Harvard College Observatory and designated HV 4013. It was considered to be the brightest variable star in M31 Two years later it was given the variable star designation AF Andromedae. Between 1917 and 1953, five or six major eruptions were detected and two or three minor ones. More eruptions were observed in 1970-74, 1987-92, 1998-2001, and 2017. AF And was often referred to as var 19, after its number in a Hubble list of variable stars in M31 and M33. It was identified as one of the five Hubble–Sandage variables: Var A, Var B, Var C, and Var 2 in M33, and Var 19 in M31. On the basis of color–color comparisons, it was assigned as spectral type B and described as related to the P Cygni var ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

P Cygni
P Cygni (34 Cygni) is a variable star in the constellation Cygnus. The designation "P" was originally assigned by Johann Bayer in ''Uranometria'' as a nova. Located about 5,300 light-years (1,560 parsecs) from Earth, it is a hypergiant luminous blue variable (LBV) star of spectral type B1-2 Ia-0ep that is one of the most luminous stars in the Milky Way. Visibility The star is located about 5,000 to 6,000 light-years (1,500–1,800 parsecs) from Earth. Despite this vast distance, it is visible to the naked eye in suitable dark sky locations. It was unknown until the end of the 16th century, when it suddenly brightened to 3rd magnitude. It was first observed on 18 August (Gregorian) 1600 by Willem Janszoon Blaeu, a Dutch astronomer, mathematician and globe-maker. Bayer's atlas of 1603 assigned it the miscellaneous label P and the name has stuck ever since. After six years the star faded slowly, dropping below naked-eye visibility in 1626. It brightened again in 1655, bu ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Objects With Variable Star Designations
Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an aim, target, or objective * Object (grammar), a sentence element, such as a direct object or an indirect object Science, technology, and mathematics Computing * 3D model, a representation of a physical object * Object (computer science), a language mechanism for binding data with methods that operate on that data ** Object-orientation, in which concepts are represented as objects *** Object-oriented programming (OOP), in which an object is an instance of a class or array ** Object (IBM i), the fundamental unit of data storage in the IBM i operating system * Object (image processing), a portion of an image interpreted as a unit * Object file, the output of a compiler or other translator program (also known as "object code") * Object, an in ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Luminous Blue Variables
Luminous may refer to: * Luminous flame, a flame emitting visible light Music * Luminous (group), a South Korean boy band * Luminous (EP), ''Luminous'' (EP), an EP by Cesium 137 * Luminous (John Hicks and Elise Wood album), ''Luminous'' (John Hicks and Elise Wood album), 1985–88 * Luminous (The Horrors album) * Luminous, an album by Chris Murphy (violinist), Chris Murphy * Luminous, an album by Bill Nelson (musician), Bill Nelson * Luminous (ClariS song), "Luminous" (ClariS song), 2012 * Luminous (Jedward song), 2012 Other uses * Luminous (book), ''Luminous'' (book), a 1998 short story collection by Greg Egan * Luminous (typeface), a foundry type made by Ludwig & Mayer * Luminous Studio, a video game engine developed by Square Enix * Project Luminous, a project by the Walt Disney Corporation that became the sub franchise ''Star Wars: High Republic'' See also

* * * Luminance * Luminescence * Luminosity * ''Lumines'', a video game {{disambiguation ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




Extragalactic Stars
Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy. The closest objects in extragalactic astronomy include the galaxies of the Local Group, which are close enough to allow very detailed analyses of their contents (e.g. supernova remnants, stellar associations). As instrumentation has improved, distant objects can now be examined in more detail and so extragalactic astronomy includes objects at nearly the edge of the observable universe. Research into distant galaxies (outside of our local group) is valuable for studying aspects of the universe such as galaxy evolution and Active Galactic Nuclei (AGN) which give insight into physical phenomena (e.g. super massive black hole accretion and the presence of dark matter). It is through extragalactic astronomy that astronomers and physicists are able to study the effects of General ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


M31-RV
M31-RV is a possible red cataclysmic variable star located in the Andromeda Galaxy (M31) that experienced an outburst in 1988, which is similar to the outburst V838 Monocerotis experienced in 2002. Such objects have been called luminous red novae or intermediate-luminosity red transients. During the outburst, both V838 Mon and M31-RV reached a maximum absolute visual magnitude of -9.8. In 2006, the area around M31-RV was observed using the Hubble Space Telescope, but only red giants were seen. It is thought that the star either became too dim for Hubble to see, or the star is a companion of one of the red giants, or the star is one of the red giants themselves. M31-RV reached a peak visual magnitude of 17 before fading rapidly and showing dust formation. The most likely explanation states that these outbursts occur during stellar merger events. See also * AE Andromedae AE Andromedae (AE And) is a luminous blue variable (LBV), a type of variable star. The star ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


List Of Andromeda's Satellite Galaxies
The Andromeda Galaxy (M31) has satellite galaxies just like the Milky Way. Orbiting M31 are at least 13 dwarf galaxies: the brightest and largest is M110, which can be seen with a basic telescope. The second-brightest and closest one to M31 is M32. The other galaxies are fainter, and were mostly discovered only starting from the 1970s. On January 11, 2006, it was announced that Andromeda Galaxy's faint companion galaxies lie on or close to a single plane running through the Andromeda Galaxy's center. This unexpected distribution is not obviously understood in the context of current models for galaxy formation. The plane of satellite galaxies points toward a nearby group of galaxies (M81 Group), possibly tracing the large-scale distribution of dark matter. It is unknown whether the Triangulum Galaxy is a satellite of Andromeda. Table of known satellites Andromeda Galaxy's satellites are listed here by discovery (orbital distance is not known). Andromeda IV is not included in th ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Solar Luminosity
The solar luminosity (), is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal solar luminosity is defined by the International Astronomical Union to be . This does not include the solar neutrino luminosity, which would add , or , i.e. a total of (the mean energy of the solar photons is 26 MeV and that of the solar neutrinos 0.59 MeV, i.e. 2.27%; the Sun emits photons and as many neutrinos each second, of which per m2 reach the Earth each second). The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this. Determination Solar luminosity is related to solar irradiance (the solar c ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Emission Spectrum
The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an electron making a atomic electron transition, transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Therefore, spectroscopy can be used to identify elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances. Emission In physics, emission is the process by which a higher energy quantum mechanical state of a particle becomes converted to a lower one through the emission of a photon, resulting in ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Stellar Classification
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grating into a spectrum exhibiting the Continuum (spectrum), rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The ''spectral class'' of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters ''O'', ''B'', ''A'', ''F'', ''G'', ''K'', and ''M'', a sequence from the hottest (''O'' type) to the coo ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]