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M85-HCC1
M85-HCC1 is an ultracompact dwarf galaxy with a star density 1,000,000 times that of the solar neighbourhood, lying near the galaxy Messier 85. , it is the densest galaxy known. See also * List of most massive galaxies References See also * M59-UCD3 (second-densest galaxy known, as of 2015) * M60-UCD1 M60-UCD1 is an ultracompact dwarf galaxy. It is 54 million light years from Earth, close to Messier 60 (M60, NGC 4649) in the Virgo Cluster. Half of its stellar mass is in the central sphere 160 light years in diameter. Characteristics M60-U ... (another dense galaxy) {{galaxy Dwarf galaxies 20150727 Coma Berenices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M59-UCD3
M59-UCD3 is an ultra-compact dwarf galaxy located near the Messier 59 galaxy. , it is the second-densest galaxy currently observed, second to M85-HCC1. References See also * M60-UCD1 (densest galaxy known, as of 2013) * M85-HCC1 M85-HCC1 is an ultracompact dwarf galaxy with a star density 1,000,000 times that of the solar neighbourhood, lying near the galaxy Messier 85. , it is the densest galaxy known. See also * List of most massive galaxies References See also * ... (densest galaxy known, as of 2015) Virgo (constellation) Dwarf galaxies 20150727 {{galaxy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Galaxies
The following is a list of notable galaxies. There are about 51 galaxies in the Local Group (see list of nearest galaxies for a complete list), on the order of 100,000 in the Local Supercluster, and an estimated 100 billion in all of the observable universe. The discovery of the nature of galaxies as distinct from other nebulae (interstellar clouds) was made in the 1920s. The first attempts at systematic catalogues of galaxies were made in the 1960s, with the Catalogue of Galaxies and Clusters of Galaxies listing 29,418 galaxies and galaxy clusters, and with the Morphological Catalogue of Galaxies, a putatively complete list of galaxies with photographic magnitude above 15, listing 30,642. In the 1980s, the Lyons Groups of Galaxies listed 485 galaxy groups with 3,933 member galaxies. Galaxy Zoo is a project aiming at a more comprehensive list: launched in July 2007, it has classified over one million galaxy images from The Sloan Digital Sky Survey, The Hubble Space Telescope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M60-UCD1
M60-UCD1 is an ultracompact dwarf galaxy. It is 54 million light years from Earth, close to Messier 60 (M60, NGC 4649) in the Virgo Cluster. Half of its stellar mass is in the central sphere 160 light years in diameter. Characteristics M60-UCD1's mass is 140 million solar masses. Colours and lack of colour gradients indicate a uniform stellar population about 14.5±0.5 billion years old (indistinguishable from the age of the Universe). Their metallicity is similar to that of the Sun. The orbital velocity dispersion of the innermost stars exceeds 100 km/s, due to the gravity of a dense mass concentration. The galactic nucleus contains a bright and variable X-ray source, presumably a supermassive black hole with a mass of 20 million solar masses (15% of the mass of the entire galaxy). With this proportion of the mass of the black hole to that of the whole galaxy, it is one of the most black hole dominated galaxies known. M60-UCD1 is believed to be the stripped core of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (astronomy)
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 the posit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coma Berenices
Coma Berenices is an ancient asterism in the northern sky, which has been defined as one of the 88 modern constellations. It is in the direction of the fourth galactic quadrant, between Leo and Boötes, and it is visible in both hemispheres. Its name means "Berenice's Hair" in Latin and refers to Queen Berenice II of Egypt, who sacrificed her long hair as a votive offering. It was introduced to Western astronomy during the third century BC by Conon of Samos and was further corroborated as a constellation by Gerardus Mercator and Tycho Brahe. It is the only modern constellation named for a historic person. The constellation's major stars are Alpha, Beta, and Gamma Comae Berenices. They form a half square, along the diagonal of which run Berenice's imaginary tresses, formed by the Coma Star Cluster. The constellation's brightest star is Beta Comae Berenices, a 4.2-magnitude main sequence star similar to the Sun. Coma Berenices contains the North Galactic Pole and one of the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parsec
The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and is defined as the distance at which 1 au subtends an angle of one arcsecond ( of a degree). This corresponds to astronomical units, i.e. 1\, \mathrm = 1/\tan \left( \ \mathrm \right)\, \mathrm. The nearest star, Proxima Centauri, is about from the Sun. Most stars visible to the naked eye are within a few hundred parsecs of the Sun, with the most distant at a few thousand. The word ''parsec'' is a portmanteau of "parallax of one second" and was coined by the British astronomer Herbert Hall Turner in 1913 to make calculations of astronomical distances from only raw observational data easy for astronomers. Partly for this reason, it is the unit preferred in astronomy and astrophysics, though the light-year remains prominent in popular s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Galaxy
A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition. Formation One theory states that most galaxies, including dwarf galaxies, form in association with dark matter, or from gas that contains metals. However, NASA's Galaxy Evolution Explorer space probe identified new dwarf galaxies forming out of gases with low metallicity. These galaxies were located in the Leo Ring, a cloud of hydrogen and helium around two massive galaxies in the constellation Leo. Because of their small size, dwarf galaxies have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 85
Messier 85 (also known as M85 or NGC 4382 or PGC 40515 or ISD 0135852) is a lenticular galaxy, or elliptical galaxy for other authors, in the Coma Berenices constellation. It is 60 million light-years away, and it is estimated to be 125,000 light-years across. It was discovered by Pierre Méchain in 1781. It is within the outskirts of the Virgo cluster, and is relatively isolated. Properties M85 is extremely poor in neutral hydrogen and has a very complex outer structure with shells and ripples that are thought to have been caused by a merger with another galaxy that took place between 4 and 7 billion years ago, as well as a relatively young (<3 billion years old) stellar population on its centermost region, some of it in a ring, that may have been created by a late starburst. Like other massive, early-type galaxies, it has different populations of |
Dwarf Galaxies
A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition. Formation One theory states that most galaxies, including dwarf galaxies, form in association with dark matter, or from gas that contains metals. However, NASA's Galaxy Evolution Explorer space probe identified new dwarf galaxies forming out of gases with low metallicity. These galaxies were located in the Leo Ring, a cloud of hydrogen and helium around two massive galaxies in the constellation Leo. Because of their small size, dwarf galaxies have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Objects Discovered In 2015
Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. Nowadays, professi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
