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NGC 7424
NGC 7424 is a barred spiral galaxy located 37.5 million light-years away in the southern constellation Grus (the Crane). Its size (about 100,000 light-years) makes it similar to our own galaxy, the Milky Way. It is called a " grand design" galaxy because of its well defined spiral arms. One supernova and two ultraluminous X-ray sources have been discovered in NGC 7424. Characteristics NGC 7424 is intermediate between normal spirals (SA) and strongly barred galaxies (SB). Other features include the presence of a central ring-like structure and a relatively low core brightness relative to the arms. The redder color of the prominent bar indicates an older population of stars while the bright blue color of the loose arms indicates the presence of ionised hydrogen and clusters of massive young stars. NGC 7424 is listed as a member of the IC 1459 Grus Group of galaxies, but is suspected of being a "field galaxy"; that is, not gravitationally bound to any group. Supernova 2001ig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New General Catalogue'' (RNGC) by Jack W. Sulent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Cluster
Star clusters are large groups of stars. Two main types of star clusters can be distinguished: globular clusters are tight groups of ten thousand to millions of old stars which are gravitationally bound, while open clusters are more loosely clustered groups of stars, generally containing fewer than a few hundred members, and are often very young. Open clusters become disrupted over time by the gravitational influence of giant molecular clouds as they move through the galaxy, but cluster members will continue to move in broadly the same direction through space even though they are no longer gravitationally bound; they are then known as a stellar association, sometimes also referred to as a ''moving group''. Star clusters visible to the naked eye include the Pleiades, Hyades, and 47 Tucanae. Open cluster Open clusters are very different from globular clusters. Unlike the spherically distributed globulars, they are confined to the galactic plane, and are almost always found wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Eccentricity
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values between 0 and 1 form an elliptic orbit, 1 is a parabolic escape orbit (or capture orbit), and greater than 1 is a hyperbola. The term derives its name from the parameters of conic sections, as every Kepler orbit is a conic section. It is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the Galaxy. Definition In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit. The eccentricity of this Kepler orbit is a non-negative number that defines its shape. The eccentricity may take the following values: * circular orbit: ''e'' = 0 * elliptic orbit: 0 < ''e'' < 1 * [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Classification
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grating into a spectrum exhibiting the Continuum (spectrum), rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The ''spectral class'' of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters ''O'', ''B'', ''A'', ''F'', ''G'', ''K'', and ''M'', a sequence from the hottest (''O'' type) to the coo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemini Observatory
The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes provide almost complete coverage of both the northern and southern skies. They are currently among the largest and most advanced optical/infrared telescopes available to astronomers. ''(See List of largest optical reflecting telescopes)''. The National Science Foundation (NSF) of the United States, the National Research Council of Canada, CONICYT of Chile, MCTI of Brazil, and MCTIP of Argentina own and operate the Gemini Observatory. The NSF is currently (2017) the majority partner, contributing approximately 70% of the funding needed to operate and maintain both telescopes. The operations and maintenance of the observatory is managed by the Association of Universities for Research in Astronomy (AURA), through a cooperative agreement with NSF. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Latin Phrases (C-E)
__NOTOC__ This is a list of Wikipedia articles of Latin phrases and their translation into English. ''To view all phrases on a single, lengthy document, see: List of Latin phrases (full)'' The list also is divided alphabetically into twenty pages: * List of Latin phrases (A) * List of Latin phrases (B) * List of Latin phrases (C) * List of Latin phrases (D) * List of Latin phrases (E) * List of Latin phrases (F) * List of Latin phrases (G) * List of Latin phrases (H) * List of Latin phrases (I) * List of Latin phrases (L) * List of Latin phrases (M) * List of Latin phrases (N) * List of Latin phrases (O) * List of Latin phrases (P) * List of Latin phrases (Q) * List of Latin phrases (R) * List of Latin phrases (S) * List of Latin phrases (T) * List of Latin phrases (U) * List of Latin phrases (V) See also * Latin influence in English * Latinism Lists * List of abbreviations used in medical prescriptions * List of ecclesiastical abbreviations * List of German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anglo-Australian Observatory
The Australian Astronomical Observatory (AAO), formerly the Anglo-Australian Observatory, was an optical and near-infrared astronomy observatory with its headquarters in North Ryde in suburban Sydney, Australia. Originally funded jointly by the United Kingdom and Australian governments, it was managed wholly by Australia's Department of Industry, Innovation, Science, Research and Tertiary Education. The AAO operated the 3.9-metre Anglo-Australian Telescope (AAT) and 1.2-metre UK Schmidt Telescope (UKST) at Siding Spring Observatory, located near the town of Coonabarabran, Australia. In addition to operating the two telescopes, AAO staff carried out astronomical research, and designed and built astronomical instrumentation for the AAT, UKST, and other telescopes including the European Southern Observatory (ESO)'s Very Large Telescope in Chile, and the Japanese Subaru Telescope on Mauna Kea in Hawaii. UK involvement in the AAO ceased in June 2010, with the change of name and manage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HST Image Of Surviving Companion To Supernova SN 2001ig
HST may refer to: Science and technology * The Hubble Space Telescope * Harvard–MIT Program of Health Sciences and Technology * The history of science and technology * High-speed telegraphy, a radiosport * High-Speed Transfer, a USRobotics modem protocol * Highstand systems tract, in the sequence stratigraphy branch of geology Transportation * Helsinki City Transport (Swedish: ') * Heritage Shunters Trust, an English rail preservation society * InterCity 125 or High Speed Train, UK * High Street (Glasgow) railway station, Scotland, station code Other uses * Half-Square or Half Square Triangle a block in quilting * Harmonized sales tax, in Canada * Hawaii-Aleutian Standard Time (UTC−10) * Hegemonic stability theory, in international relations * Helicopter support team, in the United States Marine Corps * High Sierra Trail, in California, United States * Holden Street Theatres, Adelaide, Australia * Homestead Air Reserve Base, Florida, US, IATA code * Hospital San ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Ib And Ic Supernovae
Type Ib and Type Ic supernovae are categories of supernovae that are caused by the stellar core collapse of massive stars. These stars have shed or been stripped of their outer envelope of hydrogen, and, when compared to the spectrum of Type Ia supernovae, they lack the absorption line of silicon. Compared to Type Ib, Type Ic supernovae are hypothesized to have lost more of their initial envelope, including most of their helium. The two types are usually referred to as stripped core-collapse supernovae. Spectra When a supernova is observed, it can be categorized in the Minkowski– Zwicky supernova classification scheme based upon the absorption lines that appear in its spectrum. A supernova is first categorized as either a Type I or Type II, then subcategorized based on more specific traits. Supernovae belonging to the general category Type I lack hydrogen lines in their spectra; in contrast to Type II supernovae which do dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type II Supernova
A Type II supernova (plural: ''supernovae'' or ''supernovas'') results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, but no more than 40 to 50 times, the mass of the Sun () to undergo this type of explosion. Type II supernovae are distinguished from other types of supernovae by the presence of hydrogen in their spectra. They are usually observed in the spiral arms of galaxies and in H II regions, but not in elliptical galaxies; those are generally composed of older, low-mass stars, with few of the young, very massive stars necessary to cause a supernova. Stars generate energy by the nuclear fusion of elements. Unlike the Sun, massive stars possess the mass needed to fuse elements that have an atomic mass greater than hydrogen and helium, albeit at increasingly higher temperatures and pressures, causing correspondingly shorter stellar life spans. The degeneracy pressure of electrons and the energy generated by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Lines
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible. Types of line spectra Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy (which is connected to its frequency) to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals), the photon is absorbed. Then the energy will be spontaneously re-emitted, either as one photon at the same frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Evans (astronomer)
Robert Owen Evans, Order of Australia, OAM (20 February 1937 - 8 November 2022) was a minister (Christianity), minister of the Uniting Church in Hazelbrook, New South Wales and an amateur astronomer who holds the record for visual discoveries of supernovae (42). Ministry Evans was born on 20 February 1937 in Sydney, Australia. He graduated from the University of Sydney, majoring in philosophy and modern history. Coming from a religious family, Evans trained to become a Methodism, Methodist minister and was ordained by the New South Wales Conference in 1967. He served as a circuit preacher, circuit minister until his retirement in 1998. He is the author of a number of books on the history of evangelism. Supernova search Evans took up supernova hunting around 1955, but his first adequate instrument, a 10-inch (25 cm) Newtonian telescope was assembled only about 1968. He made his first official supernova discovery in 1981 and found nine more before using larger telescopes. Whil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
