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List Of Nearest Galaxies
This is a list of known Galaxy, galaxies within 3.8 Parsec, megaparsecs (12.4 million light-years) of the Solar System, in ascending order of heliocentric distance, or the distance to the Sun. This encompasses about 50 major Local Group galaxies, and some that are members of neighboring galaxy groups, the M81 Group and the Centaurus A/M83 Group, and some that are currently not in any defined galaxy group. The list aims to reflect current knowledge: not all galaxies within the 3.8 Mpc radius have been discovered. Nearby Dwarf galaxy, dwarf galaxies are still being discovered, and galaxies located behind the central plane of the Milky Way are extremely difficult to discern. It is possible for any galaxy to mask another located beyond it. Intergalactic distance measurements are subject to large uncertainties. Figures listed are composites of Cosmic distance ladder, many measurements, some of which may have had their individual error bars tightened to the point of no longer overlappin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies. Galaxies are categorized according to their visual morphology as elliptical, spiral, or irregular. Many are thought to have supermassive black holes at their centers. The Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than the Sun. As o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canis Major Dwarf Galaxy
The Canis Major Overdensity (''CMa Overdensity'') or Canis Major Dwarf Galaxy (''CMa Dwarf'') is a disputed dwarf irregular galaxy in the Local Group, located in the same part of the sky as the constellation Canis Major. The supposed small galaxy contains a relatively high percentage of red giants and is thought to contain an estimated one billion stars in all. At the time of its announcment, the Canis Major Dwarf Galaxy is classified as an irregular galaxy and is thought to be the closest neighboring galaxy to the Earth's location in the Milky Way, being located about away from the Solar System and from the Galactic Center. It has a roughly elliptical shape and is thought to contain as many stars as the Sagittarius Dwarf Elliptical Galaxy, the previous contender for closest galaxy to the Earth's location in the Milky Way, though later studies disputed this conclusion. Discovery The existence of a strong elliptical-shaped stellar overdensity was reported in November 2003 by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangulum II
Triangulum II (Tri II or Laevens 2) is a dwarf galaxy close to the Milky Way Galaxy. Like other dwarf spheroidal galaxies, its stellar population is very old: the galaxy was quenched before 11.5 billion years ago. It contains only 1000 stars, yet is quite massive, having a solar mass to light ratio of 3600. This is an unusually high mass for such a small galaxy. ; The distance from the centre of the Milky Way is . The luminosity is 450 times that of the Sun. This makes it one of the dimmest known galaxies. The 2D half light radius is . The galaxy was discovered in images taken by Pan-STARRS by Benjamin P. M. Laevens in 2015. Triangulum II is a candidate for detecting WIMPs as a source of dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab .... References {{ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursa Major II Dwarf
Ursa Major II Dwarf (UMa II dSph) is a dwarf spheroidal galaxy situated in the Ursa Major constellation and discovered in 2006 in the data obtained by the Sloan Digital Sky Survey. The galaxy is located approximately 30 kpc from the Sun and moves towards the Sun with the velocity of about 116 km/s. It has an elliptical (ratio of axes ~ 2:1) shape with the Effective radius, half-light radius of about 140 pc. Ursa Major II is one of the smallest and faintest satellites of the Milky Way—its integrated luminosity is about 4000 times that of the Sun (absolute visible magnitude of about −4.2), which is much lower than the luminosity of the majority of globular clusters. UMa II is even less luminous than some stars, like Canopus in the Milky Way. It is comparable in luminosity to Bellatrix in Orion (constellation), Orion. However, its mass is about 5 million solar masses, which means that galaxy's mass to light ratio is around 2000. This may be an overestimate as the ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carina III
Carina may refer to: Places Australia * Carina, Queensland, a suburb in Brisbane * Carina Heights, Queensland, a suburb in Brisbane * Carina, Victoria, a locality in Mildura Serbia * Carina, Osečina, a village in the Kolubara District People * Carina (name), a given name (including a list of people with the name) * Carina, a pet form of the given name Cara * Carina, a Latinization of Cairenn, said to be the mother of Niall of the Nine Hostages Anatomy * ''Carina'', the scientific name for an anatomical structure resembling a keel, such as the large keel on the breastbone in birds * Carina of trachea, the point at which the trachea branches to form the two mainstem bronchi Astronomy * Carina (Chinese astronomy) * Carina (constellation), a constellation * Carina Dwarf, a dwarf galaxy orbiting the Milky Way * Carina Nebula (NGC 3372) Arts, entertainment, and media * "Carina" (Corrado Lojacono song), a 1958 song covered by Sophia Loren, Dean Martin and Cliff Richard * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrus I
Hydrus is a small constellation in the deep southern sky. It was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm (14 in) diameter celestial globe published in late 1597 (or early 1598) in Amsterdam by Plancius and Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603. The French explorer and astronomer Nicolas Louis de Lacaille charted the brighter stars and gave their Bayer designations in 1756. Its name means "male water snake", as opposed to Hydra, a much larger constellation that represents a female water snake. It remains below the horizon for most Northern Hemisphere observers. The brightest star is the 2.8-magnitude Beta Hydri, also the closest reasonably bright star to the south celestial pole. Pulsating between magnitude 3.26 and 3.33, Gamma Hydri is a variable red giant 60 times the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittarius Dwarf Elliptical Galaxy
The Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), also known as the Sagittarius Dwarf Elliptical Galaxy (Sgr dE or Sag DEG), is an elliptical loop-shaped satellite galaxy of the Milky Way. It contains four globular clusters in its main body, with the brightest of them – NGC 6715 (M54) – being known well before the discovery of the galaxy itself in 1994. Sgr dSph is roughly 10,000 light-years in diameter, and is currently about 70,000 light-years from Earth, travelling in a polar orbit (an orbit passing over the Milky Way's galactic poles) at a distance of about 50,000 light-years from the core of the Milky Way (about one third of the distance of the Large Magellanic Cloud). In its looping, spiraling path, it has passed through the plane of the Milky Way several times in the past. In 2018 the Gaia project of the European Space Agency showed that Sgr dSph had caused perturbations in a set of stars near the Milky Way's core, causing unexp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S Sgrdw1
S, or s, is the nineteenth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''ess'' (pronounced ), plural ''esses''. History Origin Northwest Semitic šîn represented a voiceless postalveolar fricative (as in 'ip'). It originated most likely as a pictogram of a tooth () and represented the phoneme via the acrophonic principle. Ancient Greek did not have a phoneme, so the derived Greek letter sigma () came to represent the voiceless alveolar sibilant . While the letter shape Σ continues Phoenician ''šîn'', its name ''sigma'' is taken from the letter ''samekh'', while the shape and position of ''samekh'' but name of ''šîn'' is continued in the '' xi''. Within Greek, the name of ''sigma'' was influenced by its association with the Greek word (earlier ) "to hiss". The original name of the letter "sigma" may have been ''san'', but due to the complica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segue 1
Segue 1 is a dwarf spheroidal galaxy or globular cluster situated in the Leo constellation and discovered in 2006 by Sloan Digital Sky Survey. It is located at a distance of about 23 kpc (about 75,000 light years) from the Sun and moves away from the Sun with the velocity of about 206 km/s. Segue 1 has a noticeably elongated (ratio of axes ~ 2:1) shape with the half-light radius of about 30 pc. This elongation may be caused by the tidal forces acting from the Milky Way galaxy if Segue 1 is being tidally disrupted now. The name is due to the fact that it was found by the SEGUE program, the Sloan Extension for Galactic Understanding and Exploration. Properties Segue 1 is one of the smallest and faintest satellites of the Milky Way—its integrated luminosity is about 300 times that of the Sun (absolute visible magnitude of about −1.5), which is much smaller than the luminosity of a typical globular cluster. Observations indicate its mass is about 600,000 solar ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly , without Extinction (astronomy), extinction (or dimming) of its light due to absorption by Interstellar medium, interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. As with all astronomical magnitude (astronomy), magnitudes, the absolute magnitude can be specified for different wavelength ranges corresponding to specified Filter (optics), filter bands or passbands; for stars a commonly quoted absolute magnitude is the absolute visual magnitude, which uses the visual (V) band of the spectrum (in the UBV phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distance Modulus
The distance modulus is a way of expressing distances that is often used in astronomy. It describes distances on a logarithmic scale based on the astronomical magnitude system. Definition The distance modulus \mu=m-M is the difference between the apparent magnitude m (ideally, corrected from the effects of interstellar absorption) and the absolute magnitude M of an astronomical object. It is related to the distance d in parsecs by: :\log_(d) = 1 + \frac :\mu=5\log_(d)-5 This definition is convenient because the observed brightness of a light source is related to its distance by the inverse square law (a source twice as far away appears one quarter as bright) and because brightnesses are usually expressed not directly, but in magnitudes. Absolute magnitude M is defined as the apparent magnitude of an object when seen at a distance of 10 parsecs. Suppose a light source has luminosity L(d) when observed from a distance of d parsecs, and luminosity L(10) when observed from a dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tucana III
Tucana (The Toucan) is a constellation of stars in the southern sky, named after the toucan, a South American bird. It is one of twelve constellations conceived in the late sixteenth century by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Tucana first appeared on a celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas ''Uranometria'' of 1603. French explorer and astronomer Nicolas Louis de Lacaille gave its stars Bayer designations in 1756. The constellations Tucana, Grus (constellation), Grus, Phoenix (constellation), Phoenix and Pavo (constellation), Pavo are collectively known as the "Southern Birds". Tucana is not a prominent constellation as all of List of stars in Tucana, its stars are third magnitude or fainter; the brightest is Alpha Tucanae with an apparent magnitude, apparent visual magnitude of 2.87. Beta Tucanae is a star system with six member stars, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
