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Vela Pulsar
The Vela Pulsar (PSR J0835-4510 or PSR B0833-45) is a radio, optical, X-ray- and gamma-emitting pulsar associated with the Vela Supernova Remnant in the constellation of Vela. Its parent Type II supernova exploded approximately 11,000–12,300 years ago (and was about 800 light-years away). Characteristics Vela is the brightest pulsar (at radio frequencies) in the sky and spins 11.195 times per second (i.e. a period of 89.33 milliseconds—the shortest known at the time of its discovery) and the remnant from the supernova explosion is estimated to be travelling outwards at . It has the third-brightest optical component of all known pulsars (V = 23.6 mag) which pulses twice for every single radio pulse. The Vela pulsar is the brightest persistent object in the high-energy gamma-ray sky. Glitches Glitches are sudden spin-ups in the rotation of pulsars. Vela is the best known of all the glitching pulsars, with glitches occurring on average every three years. Glitches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vela Pulsar Jet
Vela or Velas may refer to: Astronomy * Vela (constellation), a constellation in the southern sky (the Sails) ** Vela (Chinese astronomy) ** Vela Pulsar ** Vela X-1, a pulsing, eclipsing high-mass X-ray binary system Places *Vela Bluff, Antarctica *Vela, Dolj, Romania *Vela (Ilidža – Sarajevo), Bosnia and Herzegovina *Velas, Maharashtra, India Ships * ''CMA CGM Vela'', a container ship in service since 2008 * USNS Vela (T-AK-89), USNS ''Vela'' (T-AK-89), US Army port repair ship * Vela-class submarine, ''Vela''-class submarine, of the Indian Navy ** INS Vela (S40), INS ''Vela'' (S40), in service 1973–2010 Technology * Project Vela, a system developed by the United States to monitor compliance with the Partial Test Ban Treaty ** Vela (satellite), a series of satellites launched by the United States to monitor nuclear testing *** Vela Incident, an international incident, in which a Vela satellite is thought to possibly have observed a nuclear test * Versatile Laboratory Aid ... [...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] |
The Astrophysical Journal
''The Astrophysical Journal'', often abbreviated ''ApJ'' (pronounced "ap jay") in references and speech, is a peer-reviewed Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review ... 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Ray
A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequencies above 30 exahertz (), it imparts the highest photon energy. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation ''gamma rays'' based on their relatively strong penetration of matter; in 1900 he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power. Gamma rays from radioactive decay are in the energy range from a few kiloelectronvolts (keV) to approximately 8 megaelectronvolts (MeV), corresponding to the typical energy levels in nuclei with reasonably long lif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gérard Grisey
Gérard Henri Grisey (; ; 17 June 1946 – 11 November 1998) was a twentieth-century French composer of contemporary classical music. His work is often associated with the Spectralist Movement in music, of which he was a major pioneer. Biography Grisey was born in Belfort, on 17 June 1946. From a very young age, Grisey demonstrated enormous interest and talent in music composition and study, writing his first essay on music when he was 9 years old. He studied at the in Trossingen in Germany from 1963 to 1965 before entering the Conservatoire national supérieur de musique where he studied with Olivier Messiaen from 1965 to 1967 and again from 1968 to 1972, while also working with Henri Dutilleux at the École normale de musique in 1968. He won prizes for piano accompaniment, harmony, counterpoint, fugue, and composition at the Conservatoire under Messiaen's guidance. He also studied electroacoustics with Jean-Étienne Marie in 1969, composition with Karlheinz Stockhausen, Ian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PSR B0329+54
PSR B0329+54 is a pulsar approximately 3,460 light-years away in the constellation of Camelopardalis. It completes one rotation every 0.71452 seconds and is approximately 5 million years old. The emissions of this pulsar and the Vela Pulsar were converted into audible sound by the French composer Gérard Grisey, and used as such in the piece ''Le noir de l'étoile'' (1989–90). Planetary system In 1979, two extrasolar planets were announced to be orbiting the pulsar (being classified as pulsar planets). Later observations did not support this conclusion. More recently, a 2017 analysis indicates that a long-period pulsar planet remains a possibility. See also * PSR B1257+12 * PSR J1719-1438 PSR may refer to: Organizations * Pacific School of Religion, Berkeley, California, US * Palestinian Center for Policy and Survey Research * Physicians for Social Responsibility, US ;Political parties: * Revolutionary Socialist Party (Portuga ... References Pulsars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-mass X-ray Binary
X-ray binaries are a class of binary stars that are luminous in X-rays. The X-rays are produced by matter falling from one component, called the ''donor'' (usually a relatively normal star), to the other component, called the ''accretor'', which is very compact: a neutron star or black hole. The infalling matter releases gravitational potential energy, up to several tenths of its rest mass, as X-rays. (Hydrogen fusion releases only about 0.7 percent of rest mass.) The lifetime and the mass-transfer rate in an X-ray binary depends on the evolutionary status of the donor star, the mass ratio between the stellar components, and their orbital separation. An estimated 1041 positrons escape per second from a typical low-mass X-ray binary. Classification X-ray binaries are further subdivided into several (sometimes overlapping) subclasses, that perhaps reflect the underlying physics better. Note that the classification by mass (high, intermediate, low) refers to the optically vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vela X-1
Vela or Velas may refer to: Astronomy * Vela (constellation), a constellation in the southern sky (the Sails) ** Vela (Chinese astronomy) ** Vela Pulsar ** Vela X-1, a pulsing, eclipsing high-mass X-ray binary system Places * Vela Bluff, Antarctica *Vela, Dolj, Romania * Vela (Ilidža – Sarajevo), Bosnia and Herzegovina * Velas, Maharashtra, India Ships * '' CMA CGM Vela'', a container ship in service since 2008 * USNS ''Vela'' (T-AK-89), US Army port repair ship * ''Vela''-class submarine, of the Indian Navy ** INS ''Vela'' (S40), in service 1973–2010 Technology * Project Vela, a system developed by the United States to monitor compliance with the Partial Test Ban Treaty ** Vela (satellite), a series of satellites launched by the United States to monitor nuclear testing *** Vela Incident, an international incident, in which a Vela satellite is thought to possibly have observed a nuclear test * Versatile Laboratory Aid (VELA), a data logging tool used in education Peo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puppis A
Puppis A (Pup A) is a supernova remnant (SNR) about 100 light-years in diameter and roughly 6500–7000 light-years distant. Its apparent angular diameter is about 1 degree. The light of the supernova explosion reached Earth approximately 3700 years ago. Although it overlaps the Vela Supernova Remnant, it is four times more distant. A hypervelocity neutron star known as the Cosmic Cannonball has been found in this SNR. Puppis X-1 Puppis X-1 (Puppis A) was discovered by a Skylark flight in October 1971, viewed for 1 min with an accuracy ≥ 2 arcsec, probably at 1M 0821-426, with Puppis A ( RA 08h 23m 08.16s Dec -42° 41′ 41.40″) as the likely visual counterpart. Puppis A is one of the brightest X-ray sources in the X-ray sky. Its X-ray designation is 2U 0821-42. Gallery Image:PIA18468-SuperNova-PuppisA-XRayIR-20140821.jpg, Puppis A: X-ray lue:0.3-8 keV+ IR ed-green:24-70 microns(21 August 2014). Image:SuperNova-PuppisA-XRay-20140910.jpg, Puppis A: X-ray lue:high ree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mills Cross Telescope
The Mills Cross Telescope was a two-dimensional radio telescope built by Bernard Mills in 1954 at the Fleurs field station of the Australian Commonwealth Scientific and Industrial Research Organisation in the area known now as Badgerys Creek, about 40 km west of Sydney, New South Wales, Australia. Each arm of the cross was 1500 feet (450 m) long, running N–S and E–W, and produced a fan beam in the sky. Mills said it "consists of two rows of 250 half-wave dipole elements backed by a plane wire mesh reflector; the individual dipoles are aligned in an E-W direction." The cross operated at a frequency of 85.5 MHz (3.5m wavelength), giving a 49 arcminute beam. When the voltages of the two arms were multiplied a pencil beam was formed, but with rather high sidelobes. The beam could be steered in the sky by adjusting the phasing of the elements in each arm. Science Between 1954 and 1957, Bernard Mills, Eric R. Hill and O. Bruce Slee, using the Mills Cross, carried out a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Star
A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white holes, quark stars, and strange stars), neutron stars are the smallest and densest currently known class of stellar objects. Neutron stars have a radius on the order of and a mass of about 1.4 solar masses. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei. Once formed, they no longer actively generate heat, and cool over time; however, they may still evolve further through collision or accretion. Most of the basic models for these objects imply that neutron stars are composed almost entirely of neutrons (subatomic particles with no net electrical charge and with slightly larger mass than protons); the electro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Sydney
The University of Sydney (USYD), also known as Sydney University, or informally Sydney Uni, is a public research university located in Sydney, Australia. Founded in 1850, it is the oldest university in Australia and is one of the country's six sandstone universities. The university comprises eight academic faculties and university schools, through which it offers bachelor, master and doctoral degrees. The university consistently ranks highly both nationally and internationally. QS World University Rankings ranked the university top 40 in the world. The university is also ranked first in Australia and fourth in the world for QS graduate employability. It is one of the first universities in the world to admit students solely on academic merit, and opened their doors to women on the same basis as men. Five Nobel and two Crafoord laureates have been affiliated with the university as graduates and faculty. The university has educated eight Australian prime ministers, including ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
