HOME





Mu Muscae
Mu Muscae, Latinized from μ Muscae, is a solitary star in the southern constellation of Musca. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of around 4.75. Based upon an annual parallax shift of 7.21  mas as seen from Earth, it is located about 450 light years from the Sun. The star is drifting further away with a radial velocity of +37 km/s. This is an evolved K-type giant star with a stellar classification of K4 III, having exhausted the supply of hydrogen at its core then cooled and expanded to 53 times the Sun's radius. It most likely on the red giant branch, rather than the asymptotic giant branch, and shows no signs of mass loss. Mu Muscae is a type Lb, oxygen-rich irregular variable with a small amplitude that ranges in visual magnitude between 4.71 and 4.76. It is radiating 602 times the luminosity of the Sun from its photosphere at an effective temperature The effective temperature of a body ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Stellar Core
A stellar core is the extremely hot, dense region at the center of a star. For an ordinary main sequence star, the core region is the volume where the temperature and pressure conditions allow for energy production through thermonuclear fusion of hydrogen into helium. This energy in turn counterbalances the mass of the star pressing inward; a process that self-maintains the conditions in Thermal equilibrium, thermal and hydrostatic equilibrium. The minimum temperature required for stellar hydrogen fusion exceeds 107 Kelvin, K (), while the density at the core of the Sun is over . The core is surrounded by the stellar envelope, which transports energy from the core to the stellar atmosphere where it is radiated away into space. Main sequence Main sequence stars are distinguished by the primary energy-generating mechanism in their central region, which joins four hydrogen nuclei to form a single helium atom through thermonuclear fusion. The Sun is an example of this class of star ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Slow Irregular Variables
Slow may refer to various basic dictionary-related meanings: * Slow velocity, the rate of change of position of a moving body ** Slow speed, in kinematics, the magnitude of the velocity of an object * Slow tempo, the speed or pace of a piece of music * Slow motion, an effect in film-making * Slow reaction rate, the speed at which a chemical reaction takes place Slow, SLOW, Slowing or Slowness may also refer to: Music * Slow (band), a 1980s Canadian band Albums * ''Slow'' (Richie Kotzen album), 2001 * ''Slow'' (Starflyer 59 album), 2016 * ''Slow'' (Luna Sea album), 2005 * ''Slow'' (Ann Hampton Callaway album), 2004 * ''Slowness'' (album), an album by cantopop singer Kay Tse Songs * "Slow" (Kylie Minogue song), 2003 * "Slow" (Rumer song), 2010 * "Slow" (Matoma song), 2017 * "Slow" (Jackson Wang & Ciara song), 2023 * "Slow" (Black Midi song), 2021 * "Slow", song by The Fratellis from the album ''Eyes Wide, Tongue Tied'' (2015) * "Slow", song by Lisa Mitchell from the ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


K-type Giants
K-type may refer to: *AEC K-type The AEC K-type was a type of bus chassis built by Associated Equipment Company (AEC) from 1919 until 1926, mainly for use in London by the London General Omnibus Company (LGOC). Description The K-type was an important design that ended the ..., a bus chassis * K-type star, a stellar spectral classification * K-type filter, a type of electronic filter * K-type asteroid, an unusual kind of asteroid {{disambig ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




SIMBAD
SIMBAD (the Set of Identifications, Measurements and Bibliography for Astronomical Data) is an astronomy, astronomical database of objects beyond the Solar System. It is maintained by the Centre de données astronomiques de Strasbourg (CDS), France. SIMBAD was created by merging the Catalog of Stellar Identifications (CSI) and the Bibliographic Star Index as they existed at the Meudon Computer Centre until 1979, and then expanded by additional source data from other catalogues and the academic literature. The first on-line interactive version, known as Version 2, was made available in 1981. Version 3, developed in the C (programming language), C language and running on UNIX stations at the Volgograd Observatory, was released in 1990. Fall of 2006 saw the release of Version 4 of the database, now stored in PostgreSQL, and the supporting software, now written entirely in Java (programming language), Java. , SIMBAD contains information for 5,800,000 stars and about 5,500,000 nons ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal in astronomy, astrophysics and related fields. It publishes original research in two formats: papers (of any length) and letters (limited to five pages). MNRAS publishes more articles per year than any other astronomy journal. The learned society journal has been in continuous existence since 1827 and became online only in 2020. It operates as a partnership between the Royal Astronomical Society (RAS), who select and peer-review the contents, and Oxford University Press (OUP), who publish and market the journal. Despite its name, MNRAS is no longer monthly, nor does it carry the notices of the RAS. In 2024 MNRAS became a purely gold open access journal. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second vo ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

American Association Of Variable Star Observers
The American Association of Variable Star Observers (AAVSO) is an international nonprofit organization. Founded in 1911, the organization focuses on coordinating, analyzing, publishing, and archiving variable star observations made largely by amateur astronomers. The AAVSO creates records that establish light curves depicting the variation in brightness of a star over time. The AAVSO makes these records available to professional astronomers, researchers, and educators. Professional astronomers do not have the resources to monitor every variable star. Hence, astronomy is one of the few sciences where amateurs can make significant contributions to research. In 2011, the 100th year of the AAVSO's existence, the twenty-millionth variable star observation was received into their database. The AAVSO International Database (AID) has stored over thirty-five million observations as of 2019. The organization receives nearly 1,000,000 observations annually from an estimated amount of 2,00 ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Effective Temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known. When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature. The net emissivity may be low due to surface or atmospheric properties, such as the greenhouse effect. Star The effective temperature of a star is the temperature of a black body with the same luminosity per ''surface area'' () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total ( bolometric) luminosity of a star is then , where is the stellar radius. The definition of the stellar radius is obviously not ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Photosphere
The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Etymology The term ''photosphere'' is derived from Ancient Greek roots, φῶς, φωτός/''phos'', ''photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Various stars have photospheres of vari ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Solar Luminosity
The solar luminosity () is a unit of radiant flux (Power (physics), power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxy, 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 corresponds almost exactly to a bolometric magnitude, bolometric absolute magnitude of +4.74. The Sun is a weakly variable star, and its actual luminosity therefore Solar variation, 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 Irradiance, solar irradiance (the solar constant). Slow changes in the axial tilt of the planet and the shape of its orbit cause cyclical changes to the solar irradiance. The result is orb ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a periodic function is sometimes called the amplitude. Definitions Peak amplitude and semi-amplitude For symmetric periodic waves, like sine waves or triangle waves, ''peak amplitude'' and ''semi amplitude'' are the same. Peak amplitude In audio system measurements, telecommunications and others where the measurand is a signal that swings above and below a reference value but is not sinusoidal, peak amplitude is often used. If the reference is zero, this is the maximum absolute value of the signal; if the reference is a mean value ( DC component), the peak amplitude is the maximum ab ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




Irregular Variable
An irregular variable is a type of variable star in which variations in brightness show no regular periodicity. There are two main sub-types of irregular variable: eruptive and pulsating. Eruptive irregular variables are divided into three categories: * Group I variables are split into subgroups IA (spectral types O to A) and IB (spectral types F through M). * Orion variables, GCVS type IN (irregular and nebulous), indigenous to star-forming regions, may vary by several magnitudes with rapid changes of up to 1 magnitude in 1 to 10 days, are similarly divided by spectral type into subgroups INA and INB, but with the addition of another subgroup, INT, for T Tauri stars, or INT(YY) for YY Orionis stars. * The third category of eruptive irregulars are the IS stars, which show rapid variations of 0.5 to 1 magnitude in a few hours or days; again, these come in subgroups ISA and ISB. Pulsating irregular giants or supergiants, called slow irregular variable A slow irregular variable (a ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]