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HD 74438
HD 74438 is a spectroscopic quadruple stellar system composed of a pair of double star systems approximately 425 light years from Earth, located in open cluster IC 2391. With an estimated age of million years, HD 74438 is the youngest quadruple star system known. The outer orbital period of the system, estimated at around 5.7 years, is also among the shortest of quadruple systems. The HD 74438 system was confirmed to be a gravitationally bound The gravitational binding energy of a system is the minimum energy which must be added to it in order for the system to cease being in a gravitationally bound state. A gravitationally bound system has a lower (''i.e.'', more negative) gravitation ... quadruple system in 2017 from data collected in the Gaia-ESO Survey. In a paper published in 2022, HD 74438 was identified as a possible progenitor of a sub-Chandrasekhar Type Ia supernova. References {{Stars of Vela A-type main-sequence stars 074438 Vela (constellat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Binary-stars Orbiting Each Other
2 (two) is a number, numeral and digit. It is the natural number following 1 and preceding 3. It is the smallest and only even prime number. Because it forms the basis of a duality, it has religious and spiritual significance in many cultures. Evolution Arabic digit The digit used in the modern Western world to represent the number 2 traces its roots back to the Indic Brahmic script, where "2" was written as two horizontal lines. The modern Chinese and Japanese languages (and Korean Hanja) still use this method. The Gupta script rotated the two lines 45 degrees, making them diagonal. The top line was sometimes also shortened and had its bottom end curve towards the center of the bottom line. In the Nagari script, the top line was written more like a curve connecting to the bottom line. In the Arabic Ghubar writing, the bottom line was completely vertical, and the digit looked like a dotless closing question mark. Restoring the bottom line to its original horizontal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vela (constellation)
Vela is a constellation in the southern sky, which contains the Vela Supercluster. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship ''Argo Navis'', which was later divided into three parts, the others being Carina (constellation), Carina and Puppis. With an apparent magnitude of 1.8, its brightest star is the hot blue multiple star Gamma Velorum, one component of which is the brightest Wolf–Rayet star, Wolf-Rayet star in the sky. Delta Velorum, Delta and Kappa Velorum, together with Epsilon Carinae, Epsilon and Iota Carinae, form the asterism (astronomy), asterism known as the False Cross. 1.95-magnitude Delta is actually a triple or quintuple star system. History Argo Navis was one of the 48 classical constellations listed by the 2nd-century astronomer Ptolemy, and represented the ship ''Argo'', used by Jason and the Argonauts on their quest for the Golden Fleece in Greek mythology. German cartographer Johann Bayer depic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Astrophysical Journal Supplement Series
''The Astrophysical Journal'', often abbreviated ''ApJ'' (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler. The journal discontinued its print edition and became an electronic-only journal in 2015. Since 1953 ''The Astrophysical Journal Supplement Series'' (''ApJS'') has been published in conjunction with ''The Astrophysical Journal'', with generally longer articles to supplement the material in the journal. It publishes six volumes per year, with two 280-page issues per volume. ''The Astrophysical Journal Letters'' (''ApJL''), established in 1967 by Subrahmanyan Chandrasekhar as Part 2 of ''The Astrophysical Journal'', is now a separate journal focusing on the rapid publication of high-impact astronomical research. The three journals were published by the University of Chicago Press for the American Astronomical Society unt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordoba Durchmusterung
In astronomy, Durchmusterung or Bonner Durchmusterung (BD) is an astrometric star catalogue of the whole sky, compiled by the Bonn Observatory in Germany from 1859 to 1903. The name comes from ('run-through examination'), a German word used for a systematic survey of objects or data. The term has sometimes been used for other astronomical surveys, including not only stars, but also the search for other celestial objects. Special tasks include celestial scanning in electromagnetic wavelengths shorter or longer than visible light waves. Original catalog The 44 years of work on the Bonner Durchmusterung (abbreviated BD), initiated by Friedrich Argelander and largely carried out by his assistants, resulted in a catalogue of the positions and apparent magnitudes of approximately 325,000 stars to apparent magnitude 9–10. The catalogue was accompanied by charts plotting the positions of the stars, and was the basis for the '' Astronomische Gesellschaft Katalog'' (AGK) and ''Smithsoni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smithsonian Astrophysical Observatory Star Catalog
The Smithsonian Astrophysical Observatory Star Catalog is an astrometric star catalogue, created by Smithsonian Institution, a research institute. It was published by the Smithsonian Astrophysical Observatory in 1966 and contains 258,997 stars. The catalogue was compiled from various previous astrometric catalogues, and contains only stars to about ninth magnitude for which accurate proper motions were known. Names in the SAO catalogue start with the letters SAO, followed by a number. The numbers are assigned following 18 ten-degree bands of declination, with stars sorted by right ascension within each band. Online version of the SAO Catalog was created by the HEASARC in March 2001 based on ADC/CDS Catalog I/131A, which itself is originally derived from a character-coded machine-readable version of the Smithsonian Astrophysical Observatory Star Catalog (SAO, SAO Staff 1966) prepared by T.A. Nagy in 1979, and subsequently modified over the next decade or so. Examples of SA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Star Systems
A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough they can gravitationally distort their mutual outer stellar atmospheres. In some cases, these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 (one million million, or billion in long scale). As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year (365.25 days). Because it includes the time-measurement word "year", the term ''light-year'' is sometimes misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years) which derives from astrometry; it is the distance at which one astronomical unit subtends an angle of one second of arc. Defini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitationally Bound
The gravitational binding energy of a system is the minimum energy which must be added to it in order for the system to cease being in a gravitationally bound state. A gravitationally bound system has a lower (''i.e.'', more negative) gravitational potential energy than the sum of the energies of its parts when these are completely separated—this is what keeps the system aggregated in accordance with the minimum total potential energy principle. For a spherical body of uniform density, the gravitational binding energy ''U'' is given by the formula Chandrasekhar, S. 1939, ''An Introduction to the Study of Stellar Structure'' (Chicago: U. of Chicago; reprinted in New York: Dover), section 9, eqs. 90–92, p. 51 (Dover edition)Lang, K. R. 1980, ''Astrophysical Formulae'' (Berlin: Springer Verlag), p. 272 U = -\frac where ''G'' is the gravitational constant, ''M'' is the mass of the sphere, and ''R'' is its radius. Assuming that the Earth is a sphere of uniform density (which it i ... [...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 language, 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 160 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-type Main-sequence Stars
A type or type A may refer to: * A-type asteroid, a type of relatively uncommon inner-belt asteroids * A type blood, a type in the ABO blood group system * A-type inclusion, a type of cell inclusion * A-type potassium channel, a type of voltage-gated potassium channel * A type proanthocyanidin, a specific type of flavonoids * A-type star, a class of stars * Type A Dolby Noise Reduction, a type of Dolby noise-reduction system * Type A climate, a type in the Köppen climate classification * Type A flu, a type of influenza virus * Type A evaluation of uncertainty, an uncertainty in measurement that can be inferred, for example, from repeated measurement * Type A (label), a music label that for example produced the 2004 album '' What Doesn't Kill You...'' by Candiria * Type A personality, a personality type in the Type A and Type B personality theory * Type A submarine, a class of submarines in the Imperial Japanese Navy which served during the Second World War * Hemophilia type A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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