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Fornax Dwarf Galaxy
The Fornax Dwarf Spheroidal (formerly known as the Fornax System) is a dwarf elliptical galaxy in the constellation Fornax that was discovered in 1938 by Harlow Shapley. He discovered it while he was in South Africa on photographic plates taken by the 24 inch (61 cm) Bruce refractor at Boyden Observatory, shortly after he discovered the Sculptor Dwarf Galaxy. The galaxy is a satellite of the Milky Way and contains six globular clusters, an unusually high number for its size; the largest, NGC 1049, was discovered before the galaxy itself. The galaxy is also receding from the Milky Way at 53 km/s. It mostly contains population II stars, but also has populations of young and intermediate age. Globular clusters Using the Hubble Space Telescope, scientists derived a color-magnitude diagram for Fornax 4, a globular cluster within this galaxy. Unlike the globular clusters Fornax 1, 2, 3, and 5, which have horizontal branches across a wide range of colors and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (astronomy)
In astronomy, an epoch or reference epoch is a instant, 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 Astronomical object, celestial body, as they are subject to Perturbation (astronomy), 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 Perihelion and aphelion, 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 bodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 1049
NGC 1049 is a globular cluster located in the Local Group galaxy of the Fornax Dwarf, visible in the constellation of Fornax. At a distance of 460,000 light years, it is visible in moderate sized telescopes, while the parent galaxy is nearly invisible. This globular cluster was discovered by John Herschel on October 19, 1835, while the parent galaxy was discovered in 1938 by Harlow Shapley. References External links * * Globular clusters 1049 Year 1049 ( MXLIX) was a common year starting on Sunday of the Julian calendar. Events By place Byzantine Empire * Spring – Pecheneg Revolt: Emperor Constantine IX decides to transfer 15,000 Pecheneg warriors from their positi ... Fornax Milky Way Subgroup {{star-cluster-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Group
The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a " dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about and are moving toward one another with a velocity of . The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies. The two largest members, the Andromeda and the Milky Way galaxies, are both spiral galaxies with masses of about solar masses each. Each has its own system of satellite galaxies: * The Andromeda Galaxy's satellite system consists of Messier 32 (M32), Messier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Elliptical Galaxies
Dwarf elliptical galaxies (dEs) are elliptical galaxy, elliptical galaxies that are smaller than ordinary elliptical galaxy, galaxies. They are quite common in galaxy groups and galaxy cluster, clusters, and are usually companions to other galaxies. Examples "Dwarf elliptical" galaxies should not be confused with the rare "compact elliptical" galaxy class, of which Messier 32, M32, a satellite of the Andromeda Galaxy, is the prototype. In 1944 Walter Baade confirmed dwarf ellipticals NGC 147 and NGC 185 as members of the Local Group by resolving them into individual stars, thanks to their relatively little distance. In the 1950s, dEs were also discovered in the nearby Fornax Cluster, Fornax and Virgo Cluster, Virgo clusters. Relation to other elliptical galaxy types Dwarf elliptical galaxies have blue absolute magnitudes within the range fainter than ordinary elliptical galaxies. The surface brightness profiles of ordinary elliptical galaxy, elliptical galaxies was formerly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 be ... [...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) — 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 unexpected rippling movements of the stars trig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terzan 7
Terzan 7 is a sparse and young globular cluster that is believed to have originated in the Sagittarius Dwarf Spheroidal Galaxy (Sag DEG) and is physically associated with it. It is relatively metal rich with and an estimated age of 7.5 Gyr. Terzan 7 has low levels of nickel ( i/Fe= -0.2) which supports its membership in the Sag DEG system since it has a similar chemical signature. It has a rich population of blue stragglers that are strongly concentrated toward the center of Terzan 7. It has an average luminosity distribution of Mv = -5.05. It has a half-light radius (Rh) of 6.5pc. History Terzan 7 was the brightest of six globulars discovered by Turkish-Armenian astronomer Agop Terzan in 1968. Young globular Nearly all globular clusters of the Milky Way's galactic halo formed at the same time (12-15 Gyr). Even the far situated NGC 2419 (~100 kpc from Galactic Center) has a similar age. This trend also applies to the age of globulars found in the Large Mage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
