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LS 5039
LS 5039 is a binary system in the constellation of Scutum. It has an apparent magnitude of 11.27, and it is about 8,200 light-years away. LS 5039 consists of a massive O-type main-sequence star, and a compact object (likely a black hole) that emits HE (high energy) and VHE ( very high energy) gamma rays. It is one of the only three known star systems of this kind, together with LS I +61 303 and PSR B1259-63. The two objects orbit each other every 3.9 days, along a moderately eccentric orbit. Additionally, it is one of the few massive X-ray binaries known to be associated with radio emission. References External linksDiscovery of Very High Energy Gamma Rays Associated with an X-ray Binary(Science Express) July 7, 2005(ScienceDaily) May 19, 2006 See also *LS I +61 303 LS I +61 303 is a microquasar, a binary system containing a massive star and a compact object. The compact object is a pulsar and the system is around 7,000 light-years away. Discovery LS I + ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Systems
A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a ''star cluster'' or ''galaxy'', although, broadly speaking, they are also star systems. Star systems are not to be confused with planetary systems, which include planets and similar bodies (such as comets). A star system of two stars is known as a ''binary star'', ''binary star system'' or ''physical double star''. If there are no tidal effects, no perturbation from other forces, and no transfer of mass from one star to the other, such a system is stable, and both stars will trace out an elliptical orbit around the barycenter of the system indefinitely. ''(See Two-body problem)''. Examples of binary systems are Sirius, Procyon and Cygnus X-1, the last of which probably consists of a star and a black hole. Multiple star systems A multiple star system consists of three or more stars that appear fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TIC Objects
A tic is a sudden, repetitive, nonrhythmic motor movement or vocalization involving discrete muscle groups.American Psychiatric Association (2000)DSM-IV-TR: Tourette's Disorder.''Diagnostic and Statistical Manual of Mental Disorders'', 4th ed., text revision (DSM-IV-TR), . Available at BehaveNet.com Retrieved on August 10, 2009. Tics can be invisible to the observer, such as abdominal tensing or toe crunching. Common motor and phonic tics are, respectively, eye blinking and throat clearing. Tics must be distinguished from movements of disorders such as chorea, dystonia and myoclonus; the compulsions of obsessive–compulsive disorder (OCD) and seizure activity; and movements exhibited in stereotypic movement disorder or among autistic people (also known as stimming). Classification Tics are classified as either motor or phonic, and simple or complex. Motor or phonic Motor tics are movement-based tics affecting discrete muscle groups. Phonic tics are involuntary sounds prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Objects With Variable Star Designations
Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an aim, target, or objective * Object (grammar), a sentence element, such as a direct object or an indirect object Science, technology, and mathematics Computing * 3D model, a representation of a physical object * Object (computer science), a language mechanism for binding data with methods that operate on that data ** Object-orientation, in which concepts are represented as objects *** Object-oriented programming (OOP), in which an object is an instance of a class or array ** Object (IBM i), the fundamental unit of data storage in the IBM i operating system * Object (image processing), a portion of an image interpreted as a unit * Object file, the output of a compiler or other translator program (also known as "object code") * Object, an in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microquasars
A microquasar, the smaller version of a quasar, is a compact region surrounding a stellar black hole with a mass several times that of its companion star. The matter being pulled from the companion star forms an accretion disk around the black hole. This accretion disk may become so hot, due to friction, that it begins to emit X-rays. The disk also projects narrow streams or " jets" of subatomic particles at near-light speed, generating a strong radio wave emission. Overview In 1979, SS 433 became the first microquasar to be discovered. It was thought to be the most exotic case until similar objects such as GRS 1915+105 were discovered in 1994. In some cases, blobs or "knots" of brighter plasma within the jets appear to be traveling faster than the speed of light, an optical illusion called superluminal motion which is caused by sub-light-speed particles being projected at a small angle relative to the observer. The 1996 Bruno Rossi Prize of the American Astronomical Society was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Emission
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (shorter than a grain of rice); at 30 Hz the corresponding wavelength is (longer than the radius of the Earth). Like all electromagnetic waves, radio waves in a vacuum travel at the speed of light, and in the Earth's atmosphere at a close, but slightly lower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical objects, and are part of the blackbody radiation emitted by all warm objects. Radio waves are generated artificially by an electronic device called a transmitter, which is connected to an antenna which radiates the waves. They are received by another antenna connected to a radio receiver, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PSR B1259-63
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 (Portugal) (''Partido Socialista Revolucionário'') * Romanian Socialist Party (present-day) Places * Abruzzo Airport (IATA airport code), near Pescara, Italy * Pasir Ris MRT station (MRT station abbreviation), Singapore * Pioneer Scout Reservation, a Boy Scout camp in Ohio, US Science and technology * Pulsar, a kind of star * Primary radar * Perimeter surveillance radar * Posthumous sperm retrieval from dead men Computing * PHP Standard Recommendation * Predictive state representation of a system * Problem Steps Recorder, psr.exe, a Microsoft utility * Panel Self-Refresh in Embedded DisplayPort Law enforcement and military * US Precision Sniper Rifle * PSR-90, a Pakistani Precision Sniper Rifle Other uses * Portuguese Sign Language (IS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LS I +61 303
LS I +61 303 is a microquasar, a binary system containing a massive star and a compact object. The compact object is a pulsar and the system is around 7,000 light-years away. Discovery LS I +61 303 is an 11th-magnitude star that was recognised as a luminous object and catalogued as an OB star in 1959. It was included in the Hipparcos survey as HIP 12469 and had its parallax measured at milliarcseconds (mas), revised to − mas in the new reduction. The first ''Gaia'' data release gave a parallax of mas. The galactic radio source GT 0236+610 was found at the same position as LS I +61 303. A gamma-ray source 2CG 135+01 was found within a degree of its position, and the MAGIC telescope confirmed that LS I +61 303 was the source of the gamma rays. Periodic X-ray outbursts also occur. Binary system LS I +61 303 shows the spectrum of a Be star, a B0 main sequence star with disk that produces emission lines in its spectrum. Variations in its radial velocity show that it is i ... [...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] |
Light Curve
In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequency interval or band. Light curves can be periodic, as in the case of eclipsing binaries, Cepheid variables, other periodic variables, and transiting extrasolar planets, or aperiodic, like the light curve of a nova, a cataclysmic variable star, a supernova or a microlensing event or binary as observed during occultation events. The study of the light curve, together with other observations, can yield considerable information about the physical process that produces it or constrain the physical theories about it. Variable stars Graphs of the apparent magnitude of a variable star over time are commonly used to visualise and analyse their behaviour. Although the categorisation of variable star types is increasingly done from their s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very-high-energy Gamma Ray
Very-high-energy gamma ray (VHEGR) denotes gamma radiation with photon energies of 100 GeV (gigaelectronvolt) to 100 TeV (teraelectronvolt), i.e., 1011 to 1014 electronvolts. This is approximately equal to wavelengths between 10−17 and 10−20 meters, or frequencies of 2 × 1025 to 2 × 1028 Hz. Such energy levels have been detected from emissions from astronomical sources such as some binary star systems containing a compact object. For example, radiation emitted from Cygnus X-3 has been measured at ranges from GeV to exaelectronvolt-levels. Other astronomical sources include BL Lacertae, 3C 66A Markarian 421 and Markarian 501. Various other sources exist that are not associated with known bodies. For example, the H.E.S.S. catalog contained 64 sources in November 2011. Detection Instruments to detect this radiation commonly measure the Cherenkov radiation produced by secondary particles generated from an energetic photon entering the Earth's atmosphere. This method is calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
O-type Main-sequence Star
An O-type main-sequence star (O V) is a main-sequence (core hydrogen-burning) star of spectral type O and luminosity class V. These stars have between 15 and 90 times the mass of the Sun and surface temperatures between 30,000 and 50,000 K. They are between 40,000 and 1,000,000 times as luminous as the Sun. Spectral standard stars The "anchor" standards which define the MK classification grid for O-type main-sequence stars, i.e. those standards which have not changed since the early 20th century, are (O7 V) and (O9 V). The Morgan–Keenan–Kellerman (MKK) "Yerkes" atlas from 1943 listed O-type standards between O5 and O9, but only split luminosity classes for the O9s. The two MKK O9 V standards were Iota Orionis and . The revised Yerkes standards ("MK") presented listed in Johnson & Morgan (1953) presented no changes to the O5 to O8 types, and listed 5 O9 V standards (, , , , 10 Lacertae) and 3 O9.5 V standards (, Sigma Orionis, Zeta Op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
