“pulsar”的概念、定义、翻译、参考文献-科学参考

pulsar

Physics

A celestial source of radiation emitted in brief (0.03 to 4 seconds) regular pulses. First discovered in 1968, pulsars are believed to be rotating neutron stars. The strong magnetic field of the neutron star concentrates charged particles in two regions and the radiation is emitted in two directional beams. The pulsing effect occurs as the beams rotate. Most pulsars are radio sources (emit electromagnetic radiation of radio frequencies) but a few that emit light or X-rays have been detected. Over 300 pulsars are now known in our Galaxy and about 2500 have been detected overall. The term originated as a contraction of ‘pulsating star’.

Astronomy

A radio source from which is received a highly regular train of pulses. As of 2017, over 2500 pulsars had been catalogued since the first was discovered in 1967. Pulsars are rapidly spinning neutron stars, 20–30 km in diameter. The stars are highly magnetized (about 10⁸ tesla), with the magnetic axis inclined to the spin axis. The radio emission arises from the acceleration of charged particles spiralling in the magnetic field lines above the magnetic poles. As the star rotates, a beam of radio waves sweeps across the Earth and a pulse is seen, much like the beam from a lighthouse. Pulse periods are typically 1 s, but range from 1.4 ms (millisecond pulsars) to over 20 s. The pulse periods are lengthening gradually as the neutron stars lose rotational energy, but a few young pulsars are prone to abrupt disturbances known as glitches. Precise timing of pulses has revealed the existence of binary pulsars, and two pulsars, PSR 1257+12 and PSR B1620-26, have been shown to be accompanied by objects of planetary mass. Optical flashes have been detected from a few pulsars, notably the Crab and Vela Pulsars.
Most pulsars are believed to have been created in supernova explosions by the collapse of the core of a supergiant star some 10 times or more the mass of our Sun, but there is now considerable evidence that at least some of them originate from white dwarfs that have collapsed into neutron stars following accretion of mass from a companion star (see recycled pulsar). The great majority of known pulsars are members of the Milky Way and are concentrated in the galactic plane. There are estimated to be about 200 000 pulsars in the Galaxy, but allowing for those whose beam does not pass across us, there could be a million. Observations of interstellar dispersion (2) and the Faraday effect in pulsars provides information about the distribution of free electrons and magnetic fields in the Milky Way.
Pulsars are denoted by the prefix PSR followed by the approximate position in right ascension (4 digits) and declination (2 or 3 digits), usually for equinox 1950.0. The figures may be preceded by B if the coordinates are for epoch 1950.0, or J for epoch 2000.0.
http://www.atnf.csiro.au/research/pulsar/psrcat/ Searchable database of all known pulsars, regularly updated.

Space Exploration

A celestial source that emits pulses of energy at regular intervals, ranging from a few seconds to a few thousandths of a second. Pulsars are thought to be rapidly rotating neutron stars, which flash at radio and other wavelengths as they spin. They were discovered in 1967 by Jocelyn Bell Burnell and Antony Hewish Burnell at the Hewish Burnell, Cambridge, England. The term originated as a contraction of ‘pulsating star’. Over 1 800 pulsars are now known.
Pulsars slow down as they get older, and eventually the flashes fade. Of the 500 known radio pulsars, 20 are millisecond pulsars (flashing 1 000 times a second). Such pulsars are thought to be more than a billion years old. Two pulsars, one (estimated to be 1 000 years old) in the Crab nebula and one (estimated to be 11 000 years old) in the constellation Vela, give out flashes of visible light.
Pulsars were first identified as compact radio sources regularly emitting very rapid, intense pulses of radiation. The discovery of the first, which had a period of 1.33728 seconds, was regarded with incredulity by Bell's colleagues. It was only in 1968, after three more had been located, that the Cambridge team of which she was a member announced their existence. Within a year of their discovery pulsars were identified with rapidly rotating neutron stars formed by the gravitational collapse of stars in supernova explosions.

单词	pulsar
释义	pulsar Physics A celestial source of radiation emitted in brief (0.03 to 4 seconds) regular pulses. First discovered in 1968, pulsars are believed to be rotating neutron stars. The strong magnetic field of the neutron star concentrates charged particles in two regions and the radiation is emitted in two directional beams. The pulsing effect occurs as the beams rotate. Most pulsars are radio sources (emit electromagnetic radiation of radio frequencies) but a few that emit light or X-rays have been detected. Over 300 pulsars are now known in our Galaxy and about 2500 have been detected overall. The term originated as a contraction of ‘pulsating star’. Astronomy A radio source from which is received a highly regular train of pulses. As of 2017, over 2500 pulsars had been catalogued since the first was discovered in 1967. Pulsars are rapidly spinning neutron stars, 20–30 km in diameter. The stars are highly magnetized (about 10⁸ tesla), with the magnetic axis inclined to the spin axis. The radio emission arises from the acceleration of charged particles spiralling in the magnetic field lines above the magnetic poles. As the star rotates, a beam of radio waves sweeps across the Earth and a pulse is seen, much like the beam from a lighthouse. Pulse periods are typically 1 s, but range from 1.4 ms (millisecond pulsars) to over 20 s. The pulse periods are lengthening gradually as the neutron stars lose rotational energy, but a few young pulsars are prone to abrupt disturbances known as glitches. Precise timing of pulses has revealed the existence of binary pulsars, and two pulsars, PSR 1257+12 and PSR B1620-26, have been shown to be accompanied by objects of planetary mass. Optical flashes have been detected from a few pulsars, notably the Crab and Vela Pulsars. Most pulsars are believed to have been created in supernova explosions by the collapse of the core of a supergiant star some 10 times or more the mass of our Sun, but there is now considerable evidence that at least some of them originate from white dwarfs that have collapsed into neutron stars following accretion of mass from a companion star (see recycled pulsar). The great majority of known pulsars are members of the Milky Way and are concentrated in the galactic plane. There are estimated to be about 200 000 pulsars in the Galaxy, but allowing for those whose beam does not pass across us, there could be a million. Observations of interstellar dispersion (2) and the Faraday effect in pulsars provides information about the distribution of free electrons and magnetic fields in the Milky Way. Pulsars are denoted by the prefix PSR followed by the approximate position in right ascension (4 digits) and declination (2 or 3 digits), usually for equinox 1950.0. The figures may be preceded by B if the coordinates are for epoch 1950.0, or J for epoch 2000.0. http://www.atnf.csiro.au/research/pulsar/psrcat/ Searchable database of all known pulsars, regularly updated. Space Exploration A celestial source that emits pulses of energy at regular intervals, ranging from a few seconds to a few thousandths of a second. Pulsars are thought to be rapidly rotating neutron stars, which flash at radio and other wavelengths as they spin. They were discovered in 1967 by Jocelyn Bell Burnell and Antony Hewish Burnell at the Hewish Burnell, Cambridge, England. The term originated as a contraction of ‘pulsating star’. Over 1 800 pulsars are now known. Pulsars slow down as they get older, and eventually the flashes fade. Of the 500 known radio pulsars, 20 are millisecond pulsars (flashing 1 000 times a second). Such pulsars are thought to be more than a billion years old. Two pulsars, one (estimated to be 1 000 years old) in the Crab nebula and one (estimated to be 11 000 years old) in the constellation Vela, give out flashes of visible light. Pulsars were first identified as compact radio sources regularly emitting very rapid, intense pulses of radiation. The discovery of the first, which had a period of 1.33728 seconds, was regarded with incredulity by Bell's colleagues. It was only in 1968, after three more had been located, that the Cambridge team of which she was a member announced their existence. Within a year of their discovery pulsars were identified with rapidly rotating neutron stars formed by the gravitational collapse of stars in supernova explosions.
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