|
Quintuplet Cluster
The Quintuplet cluster is a dense cluster of massive young stars about 100 light years from the Galactic Center (GC). Its name comes from the fact it has five prominent infrared sources residing in it. Along with the Arches Cluster it is one of two in the immediate GC region. Due to heavy extinction by dust in the vicinity, it is invisible to optical observation and must be studied in the X-ray, radio, and infrared bands. The Quintuplet is less compact than the nearby Arches Cluster, with fewer of the most massive and luminous stars, but it does have the distinction of hosting two of the extremely rare luminous blue variables, the Pistol Star and the less well-known qF 362 (aka V4650 Sgr), and a third just a few parsecs away. It also contains a number of red supergiants, all suggesting a slightly more evolved cluster around 4 million years old. Discovery and naming The Quintuplet was originally identified in 1983 as a pair of infra-red sources in a 2.5 micron survey of the ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quintuplet Cluster Region (1002
A multiple birth is the culmination of one multiple pregnancy, wherein the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such births are often named according to the number of offspring, as in ''twins'' and ''triplets''. In non-humans, the whole group may also be referred to as a '' litter'', and multiple births may be more common than single births. Multiple births in humans are the exception and can be exceptionally rare in the largest mammals. A multiple pregnancy may be the result of the fertilization of a single egg that then splits to create identical fetuses, or it may be the result of the fertilization of multiple eggs that create fraternal ("non-identical") fetuses, or it may be a combination of these factors. A multiple pregnancy from a single zygote is called ''monozygotic'', from two zygotes is called '' dizygotic'', or from three or more zygotes is cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WR 102dd
WR may refer to: Arts and media * '' W.R.: Mysteries of the Organism'', a Serbian film, * Wikipedia Review, an Internet forum for the discussion of Wikimedia projects, particularly the English Wikipedia. *Willie Revillame, a Philippine TV host * Wiltshire Radio, original name of Heart Wiltshire, an English radio station Businesses and organizations * WR, IATA airline designator for WestJet Encore * Welter Racing, a French sports car maker * Western Railway zone, India Places * WR postcode area, England * WR Draw, a bridge over the Passaic River, in New Jersey, US Science and technology * Band 3, a protein (HGNC code WR) * Wasserman reaction is an antibody test for syphilis, based on complement-fixation * Wolf-Rayet galaxy, a galaxy which contains large numbers of Wolf-Rayet stars * Wreath product, a concept from group theory Sport * Wide receiver, a position in American football * World record, the best result ever in for example a sport using measurement * World Rugby, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Supergiant
Red supergiants (RSGs) 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. Betelgeuse and Antares are the brightest and best known red supergiants (RSGs), indeed the only first magnitude red supergiant stars. Classification Stars are classified as supergiants on the basis of their spectral luminosity class. This system uses certain diagnostic spectral lines to estimate the surface gravity of a star, hence determining its size relative to its mass. Larger stars are more luminous at a given temperature and can now be grouped into bands of differing luminosity. The luminosity differences between stars are most apparent at low temperatures, where giant stars are much brighter than main-sequence stars. Supergiants have the lowest surface gravities and hence are the largest and brightest at a particular temperature. The ''Yerkes'' o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V4998 Sagittarii
V4998 Sagittarii is a luminous blue variable star (LBV) in the constellation of Sagittarius. Located some 25,000 light years away, the star is positioned about 7 pc (23 ly) away from a starburst cluster known as the Quintuplet cluster. It has an ejection nebula measuring over 0.8 pc in diameter, formed 5000-10,000 years ago through large eruptions. The star has a large mass comparable to the Pistol star and a luminosity of around 4,000,000 times the Sun (). This places the star as one of the most massive and luminous stars known. Observational history The star was first discovered in a 1993 survey that searched for bright near-infrared sources within 0.55°2 of the Galactic Center. The survey used 1–20 micron photometry and used a two channel InSb detector on the 1 meter ANU telescope in Australia. 50 objects were targeted and most of them had bolometric magnitudes below -5. The star itself was observed in May 1987. Its position, ''JHKLNMQ'' magnitudes, right ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Initial Mass Function
In astronomy, the initial mass function (IMF) is an empirical function that describes the initial distribution of masses for a population of stars. The IMF is an output of the process of star formation. The IMF is often given as a probability distribution function (PDF) for the mass at which a star enters the main sequence (begins hydrogen fusion). The distribution function can then be used to construct the mass distribution (the histogram of stellar masses) of a population of stars. It differs from the ''present day mass function'' (PDMF), the current distribution of masses of stars, due to the evolution and death of stars which occurs at different rates for different masses as well as dynamical mixing in some populations. The properties and evolution of a star are closely related to its mass, so the IMF is an important diagnostic tool for astronomers studying large quantities of stars. For example, the initial mass of a star is the primary factor determining its colour, lumi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral
In mathematics, an integral assigns numbers to functions in a way that describes displacement, area, volume, and other concepts that arise by combining infinitesimal data. The process of finding integrals is called integration. Along with differentiation, integration is a fundamental, essential operation of calculus,Integral calculus is a very well established mathematical discipline for which there are many sources. See and , for example. and serves as a tool to solve problems in mathematics and physics involving the area of an arbitrary shape, the length of a curve, and the volume of a solid, among others. The integrals enumerated here are those termed definite integrals, which can be interpreted as the signed area of the region in the plane that is bounded by the graph of a given function between two points in the real line. Conventionally, areas above the horizontal axis of the plane are positive while areas below are negative. Integrals also refer to the concept of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernova
A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the ''progenitor'', either collapses to a neutron star or black hole, or is completely destroyed. The peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months. Supernovae are more energetic than novae. In Latin, ''nova'' means "new", referring astronomically to what appears to be a temporary new bright star. Adding the prefix "super-" distinguishes supernovae from ordinary novae, which are far less luminous. The word ''supernova'' was coined by Walter Baade and Fritz Zwicky in 1929. The last supernova to be directly observed in the Milky Way was Kepler's Supernova in 1604, appea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Isochrone
In stellar evolution, an isochrone is a curve on the Hertzsprung-Russell diagram, representing a population of stars of the same age but with different mass. The Hertzsprung-Russell diagram plots a star's luminosity against its temperature, or equivalently, its color. Stars change their positions on the HR diagram throughout their life. Newborn stars of low or intermediate mass are born cold but extremely luminous. They contract and dim along the Hayashi track, decreasing in luminosity but staying at roughly the same temperature, until reaching the main sequence directly or by passing through the Henyey track. Stars evolve relatively slowly along the main sequence as they fuse hydrogen, and after the vast majority of their lifespan, all but the least massive stars become giants. They then evolve quickly towards their stellar endpoints: white dwarfs, neutron stars, or black holes. Isochrones can be used to date open clusters because their members all have roughly the same age. O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Red Supergiant")
