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pulsar
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{{short description|Rapidly rotating neutron star}}{{About|a type of neutron star|other uses}}File:PIA18848-PSRB1509-58-ChandraXRay-WiseIR-20141023.jpg|thumb|right|223x223px|PSR B1509â58 â X-rays from Chandra are gold; Infrared from WISE in red, green and blue/max.]](File:Pulsar anim.ogv|thumb|right|Animation of a rotating pulsar. The sphere in the middle represents the neutron star, the curves indicate the magnetic field lines and the protruding cones represent the emission zones.)File:Lightsmall-optimised.gif|thumb|Illustration of the “lighthouselighthouseA pulsar (from pulsating radio source)BOOK, Handbook of Pulsar Astronomy, Nora Roberts, D. R. Lorimer, M. Kramer, illustrated, herdruk, Cambridge University Press, 2005, 9780521828239, 249,books.google.com/books?id=OZ8tdN6qJcsC, Extract of page 249 {{Webarchive|url=https://web.archive.org/web/20221116004442books.google.com/books?id=OZ8tdN6qJcsC&pg=PA249 |date=2022-11-16 }}WEB,www.merriam-webster.com/dictionary/pulsar, Definition of PULSAR, www.merriam-webster.com, 31 May 2023, is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles.WEB,www.nasa.gov/feature/goddard/2019/nasa-s-nicer-delivers-best-ever-pulsar-measurements-1st-surface-map, NASA’s NICER Delivers Best-ever Pulsar Measurements, 1st Surface Map, 11 December 2019, This radiation can be observed only when a beam of emission is pointing toward Earth (similar to the way a lighthouse can be seen only when the light is pointed in the direction of an observer), and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays. (See also centrifugal mechanism of acceleration.)The periods of pulsars make them very useful tools for astronomers. Observations of a pulsar in a binary neutron star system were used to indirectly confirm the existence of gravitational radiation. The first extrasolar planets were discovered in 1992 around a pulsar, specifically PSR B1257+12. In 1983, certain types of pulsars were detected that, at that time, exceeded the accuracy of atomic clocks in keeping time.WEB,www.nytimes.com/1983/02/09/us/pulsar-termed-most-accurate-clock-in-sky.html, PULSAR TERMED MOST ACCURATE ‘CLOCK’ IN SKY, Sullivan, Walter, The New York Times, NY Times, February 9, 1983, January 15, 2018, - the content below is remote from Wikipedia
- it has been imported raw for GetWiki
History of observation
Discovery
Signals from the first discovered pulsar were initially observed by Jocelyn Bell while analyzing data recorded on August 6, 1967, from a newly commissioned radio telescope that she helped build. Initially dismissed as radio interference by her supervisor and developer of the telescope, Antony Hewish,NEWS, Proudfoot, Ben, She Changed Astronomy Forever. He Won the Nobel Prize For It - In 1967, Jocelyn Bell Burnell made an astounding discovery. But as a young woman in science, her role was overlooked.,www.nytimes.com/2021/07/27/opinion/pulsars-jocelyn-bell-burnell-astronomy.html, July 27, 2021, The New York Times, July 27, 2021, WEB,www.youtube.com/watch?v=NDW9zKqvPJI, I Changed Astronomy Forever. He Won the Nobel Prize for It. | ‘Almost Famous’ by Op-Docs, YouTube, the fact that the signals always appeared at the same declination and right ascension soon ruled out a terrestrial source. On November 28, 1967, Bell and Hewish using a fast strip chart recorder resolved the signals as a series of pulses, evenly spaced every 1.337 seconds.JOURNAL, Hewish, A., Bell, S. J., Pilkington, J. D. H., Scott, P. F., Collins, R. A., Observation of a Rapidly Pulsating Radio Source, Nature, February 1968, 217, 5130, 709â713, 10.1038/217709a0, 1968Natur.217..709H, 4277613,www.nature.com/articles/217709a0, en, 1476-4687, No astronomical object of this nature had ever been observed before. On December 21, Bell discovered a second pulsar, quashing speculation that these might be signals beamed at earth from an extraterrestrial intelligence.JOURNAL,phys.org/news/2017-11-fifty-years-jocelyn-bell-pulsars.html, November 28, 2017, Fifty years ago, Jocelyn Bell discovered pulsars and changed our view of the universe, George Hobbs, Simon Johnston, phys.org, August 4, 2021, Pranab Ghosh, Rotation and accretion powered pulsars. World Scientific, 2007, p. 2.M. S. Longair, Our evolving universe. CUP Archive, 1996, p. 72.M. S. Longair, High energy astrophysics, Volume 2. Cambridge University Press, 1994, p. 99.When observations with another telescope confirmed the emission, it eliminated any sort of instrumental effects. At this point, Bell said of herself and Hewish that “we did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problemâif one thinks one may have detected life elsewhere in the universe, how does one announce the results responsibly?“WEB,www.bigear.org/vol1no1/burnell.htm
, Little Green Men, White Dwarfs or Pulsars?
, S. Jocelyn Bell Burnell
, Jocelyn Bell Burnell
, 1977
, Cosmic Search Magazine
, 2008-01-30
, (after-dinner speech with the title of Petit Four given at the Eighth Texas Symposium on Relativistic Astrophysics; first published in Annals of the New York Academy of Science, vol. 302, pp. 685â689, Dec. 1977).
, Little Green Men, White Dwarfs or Pulsars?
, S. Jocelyn Bell Burnell
, Jocelyn Bell Burnell
, 1977
, Cosmic Search Magazine
, 2008-01-30
Even so, they nicknamed the signal LGM-1, for “little green men” (a playful name for intelligent beings of extraterrestrial origin).
File:Chart Showing Radio Signal of First Identified Pulsar.jpg|thumb|Chart on which Jocelyn Bell first recognised evidence of a pulsar, exhibited at Cambridge University LibraryCambridge University LibraryIt was not until a second pulsating source was discovered in a different part of the sky that the “LGM hypothesis” was entirely abandoned.JOURNAL, Science, 23 April 2004, 304, 5670, 489, Bell Burnell, S. Jocelyn, So Few Pulsars, So Few Females, 10.1126/science.304.5670.489, 15105461, free, Their pulsar was later dubbed CP 1919, and is now known by a number of designators including PSR B1919+21 and PSR J1921+2153. Although CP 1919 emits in radio wavelengths, pulsars have subsequently been found to emit in visible light, X-ray, and gamma ray wavelengths.Courtland, Rachel. “Pulsar Detected by Gamma Waves Only {{Webarchive|url=https://web.archive.org/web/20150702151221www.newscientist.com/article/dn14968-first-pulsar-identified-by-its-gamma-rays-alone.html |date=2015-07-02 }}”. New Scientist, 17 October 2008.The word “pulsar” first appeared in print in 1968: {{cquote|An entirely novel kind of star came to light on Aug. 6 last year and was referred to, by astronomers, as LGM (Little Green Men). Now it is thought to be a novel type between a white dwarf and a neutron [star]. The name Pulsar is likely to be given to it. Dr. A. Hewish told me yesterday: ‘... I am sure that today every radio telescope is looking at the Pulsars.’Daily Telegraph, 21/3, 5 March 1968.}}File:Chandra-crab.jpg|thumb|Composite optical/X-ray image of the Crab Nebula, showing synchrotron emission in the surrounding pulsar wind nebulapulsar wind nebulaThe existence of neutron stars was first proposed by Walter Baade and Fritz Zwicky in 1934, when they argued that a small, dense star consisting primarily of neutrons would result from a supernova.JOURNAL, 10.1103/PhysRev.46.76.2, Remarks on Super-Novae and Cosmic Rays, 1934, Baade, W., Zwicky, F., Physical Review, 46, 1, 76, 1934PhRv...46...76B,authors.library.caltech.edu/5999/1/BAApr34.pdf, Based on the idea of magnetic flux conservation from magnetic main sequence stars, Lodewijk Woltjer proposed in 1964 that such neutron stars might contain magnetic fields as large as 1014 to 1016 gauss (=1010 to 1012 tesla).JOURNAL, Woltjer, L., X-rays and Type I Supernova Remnants, 10.1086/148028, Astrophysical Journal, 140, 1309, 1964, 1964ApJ...140.1309W,articles.adsabs.harvard.edu/pdf/1964ApJ...140.1309W, free, In 1967, shortly before the discovery of pulsars, Franco Pacini suggested that a rotating neutron star with a magnetic field would emit radiation, and even noted that such energy could be pumped into a supernova remnant around a neutron star, such as the Crab Nebula.JOURNAL, Pacini, F., Energy Emission from a Neutron Star, 10.1038/216567a0, Nature, 216, 5115, 567â568, 1967, 1967Natur.216..567P, 4282721, After the discovery of the first pulsar, Thomas Gold independently suggested a rotating neutron star model similar to that of Pacini, and explicitly argued that this model could explain the pulsed radiation observed by Bell Burnell and Hewish.JOURNAL, Gold, T., Rotating Neutron Stars as the Origin of the Pulsating Radio Sources, Nature, 218, 731â732, 1968, 10.1038/218731a0, 1968Natur.218..731G, 5143, 4217682, In 1968, Richard V. E. Lovelace with collaborators discovered period P approx 33 ms of the Crab Nebula pulsar using Arecibo Observatory.Crab nebula pulsar NP 0532 {{Webarchive|url=https://web.archive.org/web/20201119213323ui.adsabs.harvard.edu/abs/1969Natur.221..453C/abstract |date=2020-11-19 }} 1969, J. M. Comella, H. D. Craft, R. V. E. Lovelace, J. M. Sutton, G. L. Tyler Nature 221 (5179), 453â454.Digital Search Methods for Pulsars {{Webarchive|url=https://web.archive.org/web/20210420104139ui.adsabs.harvard.edu/abs/1969Natur.222..231L/abstract |date=2021-04-20 }} 1969, R. V. E. Lovelace, J. M. Sutton, E. E. Salpeter Nature 222 (5190), 231â233.The discovery of the Crab pulsar provided confirmation of the rotating neutron star model of pulsars.On the discovery of the period of the Crab Nebula pulsar {{Webarchive|url=https://web.archive.org/web/20210602075540articles.adsabs.harvard.edu/pdf/2012Obs...132..186L |date=2021-06-02 }} R. V. E. Lovelace and G. L. Tyler 2012, The Observatory, 132, 186. The Crab pulsar 33-millisecond pulse period was too short to be consistent with other proposed models for pulsar emission. Moreover, the Crab pulsar is so named because it is located at the center of the Crab Nebula, consistent with the 1933 prediction of Baade and Zwicky.Lyne & Graham-Smith, pp. 1â7 (1998).In 1974, Antony Hewish and Martin Ryle, who had developed revolutionary radio telescopes, became the first astronomers to be awarded the Nobel Prize in Physics, with the Royal Swedish Academy of Sciences noting that Hewish played a “decisive role in the discovery of pulsars”.WEB,www.nobelprize.org/nobel_prizes/physics/laureates/1974/press.html, Press Release: The Nobel Prize in Physics 1974, 2014-01-19, 15 October 1974, Considerable controversy is associated with the fact that Hewish was awarded the prize while Bell, who made the initial discovery while she was his PhD student, was not. Bell claims no bitterness upon this point, supporting the decision of the Nobel prize committee.Bell Burnell, S. Jocelyn. “Little Green Men, White Dwarfs, or Pulsars?” {{Webarchive|url=https://web.archive.org/web/20190607075821www.bigear.org/vol1no1/burnell.htm |date=2019-06-07 }}. Annals of the New York Academy of Science, vol. 302, pp. 685â689, Dec. 1977.Milestones
missing image!
- Vela Pulsar jet.jpg -
The Vela Pulsar and its surrounding pulsar wind nebula.
In 1974, Joseph Hooton Taylor, Jr. and Russell Hulse discovered for the first time a pulsar in a binary system, PSR B1913+16. This pulsar orbits another neutron star with an orbital period of just eight hours. Einstein’s theory of general relativity predicts that this system should emit strong gravitational radiation, causing the orbit to continually contract as it loses orbital energy. Observations of the pulsar soon confirmed this prediction, providing the first ever evidence of the existence of gravitational waves. As of 2010, observations of this pulsar continues to agree with general relativity.JOURNAL, Timing measurements of the relativistic binary pulsar PSR B1913+ 16
- Vela Pulsar jet.jpg -
The Vela Pulsar and its surrounding pulsar wind nebula.
, Weisberg, J.M.
, Nice, D.J.
, Taylor, J.H.
, amp
, The Astrophysical Journal
, 722
, 2
, 1030â1034
, 2010
, 1011.0718, 2010ApJ...722.1030W, 10.1088/0004-637X/722/2/1030, 118573183
, In 1993, the Nobel Prize in Physics was awarded to Taylor and Hulse for the discovery of this pulsar.WEB, Nobel Prize in Physics 1993,nobelprize.org/nobel_prizes/physics/laureates/1993/, 2010-01-07,
In 1982, Don Backer led a group that discovered PSR B1937+21, a pulsar with a rotation period of just 1.6 milliseconds (38,500 rpm).JOURNAL, D. Backer, A millisecond pulsar, Nature, 300, 5893, 315â318, 1982, 10.1038/300615a0, 1982Natur.300..615B, Kulkarni, Shrinivas R., Heiles, Carl, Davis, M. M., Goss, W. M., 4247734, Observations soon revealed that its magnetic field was much weaker than ordinary pulsars, while further discoveries cemented the idea that a new class of object, the “millisecond pulsars” (MSPs) had been found. MSPs are believed to be the end product of X-ray binaries. Owing to their extraordinarily rapid and stable rotation, MSPs can be used by astronomers as clocks rivaling the stability of the best atomic clocks on Earth. Factors affecting the arrival time of pulses at Earth by more than a few hundred nanoseconds can be easily detected and used to make precise measurements. Physical parameters accessible through pulsar timing include the 3D position of the pulsar, its proper motion, the electron content of the interstellar medium along the propagation path, the orbital parameters of any binary companion, the pulsar rotation period and its evolution with time. (These are computed from the raw timing data by Tempo, a computer program specialized for this task.) After these factors have been taken into account, deviations between the observed arrival times and predictions made using these parameters can be found and attributed to one of three possibilities: intrinsic variations in the spin period of the pulsar, errors in the realization of Terrestrial Time against which arrival times were measured, or the presence of background gravitational waves. Scientists are currently attempting to resolve these possibilities by comparing the deviations seen between several different pulsars, forming what is known as a pulsar timing array. The goal of these efforts is to develop a pulsar-based time standard precise enough to make the first ever direct detection of gravitational waves. In 2006, a team of astronomers at LANL proposed a model to predict the likely date of pulsar glitches with observational data from the Rossi X-ray Timing Explorer. They used observations of the pulsar PSR J0537â6910, that is known to be a quasi-periodic glitching pulsar. However, no general scheme for glitch forecast is known to date., Nice, D.J.
, Taylor, J.H.
, amp
, The Astrophysical Journal
, 722
, 2
, 1030â1034
, 2010
, 1011.0718, 2010ApJ...722.1030W, 10.1088/0004-637X/722/2/1030, 118573183
, In 1993, the Nobel Prize in Physics was awarded to Taylor and Hulse for the discovery of this pulsar.WEB, Nobel Prize in Physics 1993,nobelprize.org/nobel_prizes/physics/laureates/1993/, 2010-01-07,
missing image!
- Artist’s concept of PSR B1257+12 system.jpg -
Artist’s impression of the planets orbiting PSR B1257+12. The one in the foreground is planet “C”.
In 1992, Aleksander Wolszczan discovered the first extrasolar planets around PSR B1257+12. This discovery presented important evidence concerning the widespread existence of planets outside the Solar System, although it is very unlikely that any life form could survive in the environment of intense radiation near a pulsar.In 2016, AR Scorpii was identified as the first pulsar in which the compact object is a white dwarf instead of a neutron star.JOURNAL, Buckley, D. A. H., Meintjes, P. J., Potter, S. B., Marsh, T. R., Gänsicke, B. T., 2017-01-23, Polarimetric evidence of a white dwarf pulsar in the binary system AR Scorpii, Nature Astronomy, en, 1, 2, 10.1038/s41550-016-0029, 2397-3366, 0029, 1612.03185, 2017NatAs...1E..29B, 15683792, Because its moment of inertia is much higher than that of a neutron star, the white dwarf in this system rotates once every 1.97 minutes, far slower than neutron-star pulsars.JOURNAL, Marsh, T. R., Gänsicke, B. T., Hümmerich, S., Hambsch, F.-J., Bernhard, K., Lloyd, C., Breedt, E., Stanway, E. R., Steeghs, D. T., A radio-pulsing white dwarf binary star, Nature, 537, 7620, 374â377, 10.1038/nature18620, 27462808, 1607.08265, 2016Natur.537..374M, September 2016, 4451512, The system displays strong pulsations from ultraviolet to radio wavelengths, powered by the spin-down of the strongly magnetized white dwarf.- Artist’s concept of PSR B1257+12 system.jpg -
Artist’s impression of the planets orbiting PSR B1257+12. The one in the foreground is planet “C”.
Nomenclature
Initially pulsars were named with letters of the discovering observatory followed by their right ascension (e.g. CP 1919). As more pulsars were discovered, the letter code became unwieldy, and so the convention then arose of using the letters PSR (Pulsating Source of Radio) followed by the pulsar’s right ascension and degrees of declination (e.g. PSR 0531+21) and sometimes declination to a tenth of a degree (e.g. PSR 1913+16.7). Pulsars appearing very close together sometimes have letters appended (e.g. PSR 0021â72C and PSR 0021â72D).The modern convention prefixes the older numbers with a B (e.g. PSR B1919+21), with the B meaning the coordinates are for the 1950.0 epoch. All new pulsars have a J indicating 2000.0 coordinates and also have declination including minutes (e.g. PSR J1921+2153). Pulsars that were discovered before 1993 tend to retain their B names rather than use their J names (e.g. PSR J1921+2153 is more commonly known as PSR B1919+21). Recently discovered pulsars only have a J name (e.g. missing image!- Pulsar schematic.svg">thumb|Schematic view of a pulsar. The sphere in the middle represents the neutron star, the curves indicate the magnetic field lines, the protruding cones represent the emission beams and the green line represents the axis on which the star rotates.The events leading to the formation of a pulsar begin when the core of a massive star is compressed during a supernova, which collapses into a neutron star. The neutron star retains most of its angular momentum, and since it has only a tiny fraction of its progenitor’s radius (and therefore its moment of inertia is sharply reduced), it is formed with very high rotation speed. A beam of radiation is emitted along the magnetic axis of the pulsar, which spins along with the rotation of the neutron star. The magnetic axis of the pulsar determines the direction of the electromagnetic beam, with the magnetic axis not necessarily being the same as its rotational axis. This misalignment causes the beam to be seen once for every rotation of the neutron star, which leads to the “pulsed” nature of its appearance.File:Pulsar formation spinup animation.gif -
Categories
Three distinct classes of pulsars are currently known to astronomers, according to the source of the power of the electromagnetic radiation:- rotation-powered pulsars, where the loss of rotational energy of the star provides the power,
- accretion-powered pulsars (accounting for most but not all X-ray pulsars), where the gravitational potential energy of accreted matter is the power source (producing X-rays that are observable from the Earth),
- magnetars, where the decay of an extremely strong magnetic field provides the electromagnetic power.
Disrupted recycled pulsar
When two massive stars are born close together from the same cloud of gas, they can form a binary system and orbit each other from birth. If those two stars are at least a few times as massive as the Sun, their lives will both end in supernova explosions. The more massive star explodes first, leaving behind a neutron star. If the explosion does not kick the second star away, the binary system survives. The neutron star can now be visible as a radio pulsar, and it slowly loses energy and spins down. Later, the second star can swell up, allowing the neutron star to suck up its matter. The matter falling onto the neutron star spins it up and reduces its magnetic field.This is called “recycling” because it returns the neutron star to a quickly-spinning state. Finally, the second star also explodes in a supernova, producing another neutron star. If this second explosion also fails to disrupt the binary, a double neutron star binary is formed. Otherwise, the spun-up neutron star is left with no companion and becomes a “disrupted recycled pulsar”, spinning between a few and 50 times per second.PRESS RELEASE, Einstein@Home ‘citizen scientists’ in the U.S.A. and Germany discover a new pulsar in Arecibo telescope data, 2010-08-12, Max Planck Institut für Gravitationsphysik, Albert Einstein Institut, Hannover, DE,www.aei.mpg.de/pdf/pm_news/2010/PM2010_Einstein_Home_pulsar_engl.pdf, 2010-09-23, dead,www.aei.mpg.de/pdf/pm_news/2010/PM2010_Einstein_Home_pulsar_engl.pdf," title="web.archive.org/web/20100814144713www.aei.mpg.de/pdf/pm_news/2010/PM2010_Einstein_Home_pulsar_engl.pdf,">web.archive.org/web/20100814144713www.aei.mpg.de/pdf/pm_news/2010/PM2010_Einstein_Home_pulsar_engl.pdf, 2010-08-14, â Background material on “disrupted recycled pulsar” {{nowrap|PSR J2007+2722}}.Applications
The discovery of pulsars allowed astronomers to study an object never observed before, the neutron star. This kind of object is the only place where the behavior of matter at nuclear density can be observed (though not directly). Also, millisecond pulsars have allowed a test of general relativity in conditions of an intense gravitational field.Maps
Image:Pioneer plaque sun.svg|thumb|Relative position of the Sun to the center of the Galaxy and 14 pulsars with their periods denoted, shown on a Pioneer plaque ]]Pulsar maps have been included on the two Pioneer plaques as well as the Voyager Golden Record. They show the position of the Sun, relative to 14 pulsars, which are identified by the unique timing of their electromagnetic pulses, so that Earth’s position both in space and time can be calculated by potential extraterrestrial intelligence.WEB,voyager.jpl.nasa.gov/spacecraft/goldenrec1.html, Voyager â The Spacecraft, voyager.jpl.nasa.gov, Because pulsars are emitting very regular pulses of radio waves, its radio transmissions do not require daily corrections. Moreover, pulsar positioning could create a spacecraft navigation system independently, or be used in conjunction with satellite navigation.Marissa Cevallos, Science News, “How to Use a Pulsar to Find Starbucks” {{Webarchive|url=https://web.archive.org/web/20120731105649news.discovery.com/space/pulsar-navigation-gps-space.html |date=2012-07-31 }}, Discovery News, Nov 24, 2010.JOURNAL, Angelo Tartaglia, Matteo Luca Ruggiero, Emiliano Capolongo, 10.1016/j.asr.2010.10.023, Advances in Space Research, 47, A null frame for spacetime positioning by means of pulsating sources, 4, 645â653, 2011, 1001.1068, 2011AdSpR..47..645T, 118704955,Pulsar navigation
X-ray pulsar-based navigation and timing (XNAV) or simply pulsar navigation is a navigation technique whereby the periodic X-ray signals emitted from pulsars are used to determine the location of a vehicle, such as a spacecraft in deep space. A vehicle using XNAV would compare received X-ray signals with a database of known pulsar frequencies and locations. Similar to GPS, this comparison would allow the vehicle to calculate its position accurately (±5 km). The advantage of using X-ray signals over radio waves is that X-ray telescopes can be made smaller and lighter.WEB,physicsworld.com/cws/article/news/2013/jun/04/pulsars-map-the-way-for-space-missions, Pulsars map the way for space missions, 4 June 2014, Tushna, Commissariat, Physics World, WEB,www.technologyreview.com/view/515321/an-interplanetary-gps-using-pulsar-signals, An Interplanetary GPS Using Pulsar Signals, 23 May 2013, MIT Technology Review, 13 March 2021, 29 November 2014,www.technologyreview.com/view/515321/an-interplanetary-gps-using-pulsar-signals/," title="web.archive.org/web/20141129034100www.technologyreview.com/view/515321/an-interplanetary-gps-using-pulsar-signals/,">web.archive.org/web/20141129034100www.technologyreview.com/view/515321/an-interplanetary-gps-using-pulsar-signals/, dead, JOURNAL, Becker, Werner, Bernhardt, Mike G., Jessner, Axel, 1305.4842, Autonomous Spacecraft Navigation With Pulsars, Acta Futura, 7, 7, 11â28, 2013, 10.2420/AF07.2013.11, 2013AcFut...7...11B, 118570784, Experimental demonstrations have been reported in 2018.JOURNAL, NASA test proves pulsars can function as a celestial GPS, 2018, 10.1038/d41586-018-00478-8, Witze, Alexandra, Nature, 553, 7688, 261â262, 2018Natur.553..261W, free,Precise clocks
Generally, the regularity of pulsar emission does not rival the stability of atomic clocks.JOURNAL, Colloquium: Comparison of Astrophysical and Terrestrial Frequency Standards, John G. Hartnett
, Andre Luiten
, Reviews of Modern Physics
, 83
, 1
, 1â9
, 2011
, 10.1103/RevModPhys.83.1
, 1004.0115
, 2011RvMP...83....1H, 118396798
, They can still be used as external reference.JOURNAL, Matsakis, D. N., Taylor, J. H., Eubanks, T. M.,aa.springer.de/papers/7326003/2300924.pdf, A Statistic for Describing Pulsar and Clock Stabilities, Astronomy and Astrophysics, 326, 1997, 924â928, 2010-04-03, 1997A&A...326..924M, 2011-07-25,aa.springer.de/papers/7326003/2300924.pdf," title="web.archive.org/web/20110725022625aa.springer.de/papers/7326003/2300924.pdf,">web.archive.org/web/20110725022625aa.springer.de/papers/7326003/2300924.pdf, dead, For example, J0437â4715 has a period of {{val|0.005757451936712637}} s with an error of {{val|1.7|e=-17|u=s}}.
This stability allows millisecond pulsars to be used in establishing ephemeris timeJOURNAL, Backer, Don, Don Backer, The 1.5 Millisecond Pulsar, Annals of the New York Academy of Sciences, 422, 180â181, 1984,www3.interscience.wiley.com/journal/119527609/abstract,www3.interscience.wiley.com/journal/119527609/abstract," title="archive.today/20130105083556www3.interscience.wiley.com/journal/119527609/abstract,">archive.today/20130105083556www3.interscience.wiley.com/journal/119527609/abstract, dead, 2013-01-05, 10.1111/j.1749-6632.1984.tb23351.x, 2010-02-14, Eleventh Texas Symposium on Relativistic Astrophysics, 1984NYASA.422..180B, 120371785, or in building pulsar clocks.JOURNAL, World’s most accurate clock to be built in GdaÅsk, Polska Agencja Prasowa, 2010,www.naukawpolsce.pap.pl/palio/html.run?_Instance=cms_naukapl.pap.pl&_PageID=1&s=szablon.depesza&dz=szablon.depesza&dep=374908&lang=EN&_CheckSum=620107168, 2012-03-20, {{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}Timing noise is the name for rotational irregularities observed in all pulsars. This timing noise is observable as random wandering in the pulse frequency or phase.WEB,www.saao.ac.za/~wgssa/as4/urama.html, African Skies 4 â Radio Pulsar Glitch Studies, It is unknown whether timing noise is related to pulsar glitches. According to a study published in 2023,WEB, 2023-06-29, Pulsar timing irregularities reveals hidden gravitational-wave background,physicsworld.com/pulsar-timing-irregularities-reveals-hidden-gravitational-wave-background/, 2023-07-11, Physics World, en-GB, the timing noise observed in pulsars is believed to be caused by background gravitational waves. Alternatively, it may be caused by stochastic fluctuations in both the internal (related to the presence of superfluids or turbulence) and external (due to magnetospheric activity) torques in a pulsar.JOURNAL, Antonelli, Marco, Basu, Avishek, Haskell, Brynmor, 2023-02-07, Stochastic processes for pulsar timing noise: fluctuations in the internal and external torques, Monthly Notices of the Royal Astronomical Society, 520, 2, 2813â2828, 10.1093/mnras/stad256, 0035-8711, 2206.10416, , Andre Luiten
, Reviews of Modern Physics
, 83
, 1
, 1â9
, 2011
, 10.1103/RevModPhys.83.1
, 1004.0115
, 2011RvMP...83....1H, 118396798
, They can still be used as external reference.JOURNAL, Matsakis, D. N., Taylor, J. H., Eubanks, T. M.,aa.springer.de/papers/7326003/2300924.pdf, A Statistic for Describing Pulsar and Clock Stabilities, Astronomy and Astrophysics, 326, 1997, 924â928, 2010-04-03, 1997A&A...326..924M, 2011-07-25,aa.springer.de/papers/7326003/2300924.pdf," title="web.archive.org/web/20110725022625aa.springer.de/papers/7326003/2300924.pdf,">web.archive.org/web/20110725022625aa.springer.de/papers/7326003/2300924.pdf, dead, For example, J0437â4715 has a period of {{val|0.005757451936712637}} s with an error of {{val|1.7|e=-17|u=s}}.
Probes of the interstellar medium
The radiation from pulsars passes through the interstellar medium (ISM) before reaching Earth. Free electrons in the warm (8000 K), ionized component of the ISM and H II regions affect the radiation in two primary ways. The resulting changes to the pulsar’s radiation provide an important probe of the ISM itself.JOURNAL, Ferrière, Katia, The Interstellar Environment of Our Galaxy, Reviews of Modern Physics, 73, 4, 1031â1066, 2001, 10.1103/RevModPhys.73.1031, astro-ph/0106359, 2001RvMP...73.1031F, 16232084, Because of the dispersive nature of the interstellar plasma, lower-frequency radio waves travel through the medium slower than higher-frequency radio waves. The resulting delay in the arrival of pulses at a range of frequencies is directly measurable as the dispersion measure of the pulsar. The dispersion measure is the total column density of free electrons between the observer and the pulsar:
mathrm{DM} = int_0^D n_e(s) ,ds,
where D is the distance from the pulsar to the observer, and n_e is the electron density of the ISM. The dispersion measure is used to construct models of the free electron distribution in the Milky Way.JOURNAL, Taylor, J. H., Cordes, J. M., 1993ApJ...411..674T, Pulsar Distances and the Galactic Distribution of Free Electrons, 10.1086/172870, Astrophysical Journal, 411, 1993, 674, free, Additionally, density inhomogeneities in the ISM cause scattering of the radio waves from the pulsar. The resulting scintillation of the radio wavesâthe same effect as the twinkling of a star in visible light due to density variations in the Earth’s atmosphereâcan be used to reconstruct information about the small scale variations in the ISM.JOURNAL, Rickett, Barney J., 1990ARA&A..28..561R, Radio Propagation Through the Turbulent Interstellar Plasma, Annual Review of Astronomy and Astrophysics, 28, 1990, 561â605, 10.1146/annurev.aa.28.090190.003021, Due to the high velocity (up to several hundred km/s) of many pulsars, a single pulsar scans the ISM rapidly, which results in changing scintillation patterns over timescales of a few minutes.JOURNAL, Rickett, Barney J., Lyne, Andrew G., Gupta, Yashwant, 1997MNRAS.287..739R, Interstellar Fringes from Pulsar B0834+06, Monthly Notices of the Royal Astronomical Society, 287, 4, 1997, 739â752, 10.1093/mnras/287.4.739, free, The exact cause of these density inhomogeneities remains an open question, with possible explanations ranging from turbulence to current sheets.JOURNAL, Pen, Ue-Li, Levin, Yuri, Pulsar scintillations from corrugated reconnection sheets in the interstellar medium, Monthly Notices of the Royal Astronomical Society, 442, 4, 2014, 3338â3346, 10.1093/mnras/stu1020, 1302.1897, Probes of space-time
Pulsars orbiting within the curved space-time around Sgr A*, the supermassive black hole at the center of the Milky Way, could serve as probes of gravity in the strong-field regime.JOURNAL, Angelil, R., Saha, P., Merritt, D., David Merritt, Towards relativistic orbit fitting of Galactic center stars and pulsars, 1007.0007, 2010, 10.1088/0004-637X/720/2/1303, 720, 2, The Astrophysical Journal, 1303â1310, 2010ApJ...720.1303A, 118449684, Arrival times of the pulses would be affected by special- and general-relativistic Doppler shifts and by the complicated paths that the radio waves would travel through the strongly curved space-time around the black hole. In order for the effects of general relativity to be measurable with current instruments, pulsars with orbital periods less than about 10 years would need to be discovered; such pulsars would orbit at distances inside 0.01 pc from Sgr A*. Searches are currently underway; at present, five pulsars are known to lie within 100 pc from Sgr A*.JOURNAL, Deneva, J. S., Cordes, J. M., Lazio, T. J. W., Discovery of Three Pulsars from a Galactic Center Pulsar Population, The Astrophysical Journal Letters, 702, 2, L177â182, 2009, 2009ApJ...702L.177D, 10.1088/0004-637X/702/2/L177, 0908.1331, 14133127,Gravitational wave detectors
There are four consortia around the world which use pulsars to search for gravitational waves: the European Pulsar Timing Array (EPTA) in Europe, the Parkes Pulsar Timing Array (PPTA) in Australia, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) in Canada and the US, and the Indian Pulsar Timing Array (InPTA) in India. Together, the consortia form the International Pulsar Timing Array (IPTA). The pulses from Millisecond Pulsars (MSPs) are used as a system of galactic clocks. Disturbances in the clocks will be measurable at Earth. A disturbance from a passing gravitational wave will have a particular signature across the ensemble of pulsars, and will be thus detected.Significant pulsars
{{See also|Neutron star#Examples of neutron stars}}{| class=“wikitable sortable” style="text-align: center; float: right;“|+ Pulsars within 300 pc! PSR || Distance(pc) || Age(Myr)PSR J0030+0451>J0030+0451 | 244 | 7,580 |
PSR J0108â1431>J0108â1431 | 238 | 166 |
PSR J0437â4715>J0437â4715 | 156 | 1,590 |
Geminga>J0633+1746 | 156 | 0.342 |
PSR J0659+1414>J0659+1414 | 290 | 0.111 |
Vela Pulsar>J0835â4510 | 290 | 0.0113 |
PSR J0453+0755>J0453+0755 | 260 | 17.5 |
PSR J1045â4509>J1045â4509 | 300 | 6,710 |
PSR J1741â2054>J1741â2054 | 250 | 0.387 |
PSR J1856â3754>J1856â3754 | 161 | 3.76 |
PSR J2144â3933>J2144â3933 | 165 | 272 |
- The first radio pulsar “CP 1919” (now known as PSR B1919+21), with a pulse period of 1.337 seconds and a pulse width of 0.04-second, was discovered in 1967.Hewish, A., Bell, S. J., et al. “Observation of a Rapidly Pulsating Radio Source {{Webarchive|url=https://web.archive.org/web/20210804173941www.researchgate.net/publication/32005350_Observation_of_a_Rapidly_Pulsating_Radio_Source |date=2021-08-04 }}”. Nature, Volume 217, 1968 (pp. 709â713).
- The first binary pulsar, PSR 1913+16, whose orbit is decaying due to the emission of gravitational radiation at the exact rate predicted by general relativity.
- The brightest radio pulsar, the Vela Pulsar.
- The first millisecond pulsar, PSR B1937+21
- The brightest millisecond pulsar, PSR J0437â4715
- The first X-ray pulsar, Cen X-3
- The first accreting millisecond X-ray pulsar, SAX J1808.4â3658
- The first pulsar with planets, PSR B1257+12
- The first pulsar observed to have been affected by asteroids: PSR J0738â4042
- The first double pulsar binary system, PSR J0737â3039
- The shortest period pulsar, PSR J1748â2446ad, with a period of ~0.0014 seconds or ~1.4 milliseconds (716 times a second).
- The longest period neutron star pulsar, PSR J0901-4046, with a period of 75.9 seconds.
- The longest period pulsar, at 118.2 seconds, as well as one of the only known two white dwarf pulsars, AR Scorpii.JOURNAL, Buckley, D. A. H., Meintjes, P. J., Potter, S. B., Marsh, T. R., Gänsicke, B. T., 2017-01-23, Polarimetric evidence of a white dwarf pulsar in the binary system AR Scorpii, Nature Astronomy, 1, 2, 0029, 10.1038/s41550-016-0029, 2397-3366, 1612.03185, 2017NatAs...1E..29B, 15683792,
- The first white dwarf pulsar AE Aquarii.JOURNAL, Ikhsanov, Nazar R., 1998, The pulsar-like white dwarf in AE Aquarii, 1998A&A...338..521I, Astronomy and Astrophysics, en, 338, 521â526, JOURNAL, Terada, Yukikatsu, Hayashi, Takayuki, Ishida, Manabu, Mukai, Koji, Dotani, Tadayasu, Okada, Shunsaku, Nakamura, Ryoko, Naik, Sachindra, Bamba, Aya, Makishima, Kazuo, 2008-04-25, Suzaku Discovery of Hard X-Ray Pulsations from a Rotating Magnetized White Dwarf, AEAquarii, 2008HEAD...10.1003T, Publications of the Astronomical Society of Japan, en, 60, 2, 387â397, 10.1093/pasj/60.2.387, 0004-6264, free, 0711.2716,
- The pulsar with the most stable period, PSR J0437â4715
- The first millisecond pulsar with 2 stellar mass companions, PSR J0337+1715
- PSR J1841â0500, stopped pulsing for 580 days. One of only two pulsars known to have stopped pulsing for more than a few minutes.
- PSR B1931+24, has a cycle. It pulses for about a week and stops pulsing for about a month.WEB, O’Brien, Tim, Part-time pulsar yields new insight into inner workings of cosmic clocks {{!, Jodrell Bank Centre for Astrophysics | url=http://www.jb.man.ac.uk/news/2006/brakingpulsar/ |website=www.jb.man.ac.uk | access-date=23 July 2017|language=en}} One of only two pulsars known to have stopped pulsing for more than a few minutes.
- Swift J0243.6+6124 most magnetic pulsar with {{val|1.6e13|ul=G}}.JOURNAL, Kong, Ling-Da, Zhang, Shu, Zhang, Shuang-Nan, Ji, Long, Doroshenko, Victor, Santangelo, Andrea, Chen, Yu-Peng, Lu, Fang-Jun, Ge, Ming-Yu, Wang, Peng-Ju, Tao, Lian, Qu, Jin-Lu, Li, Ti-Pei, Liu, Cong-Zhan, Liao, Jin-Yuan, 2022-07-01, Insight-HXMT Discovery of the Highest-energy CRSF from the First Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124, The Astrophysical Journal Letters, 933, 1, L3, 10.3847/2041-8213/ac7711, 2206.04283, 2022ApJ...933L...3K, 249538417, 2041-8205, free, WEB, 2022-07-15, Astronomers measure strongest magnetic field ever detected,newatlas.com/space/strongest-magnetic-field-pulsar/, 2022-08-22, New Atlas, en-US,
- PSR J0952-0607 heaviest pulsar with {{val|2.35|0.17|0.17}} {{Solar mass}}.WEB, Croswell, Ken, 2022-07-22, The heaviest neutron star on record is 2.35 times the mass of the sun,www.sciencenews.org/article/heaviest-neutron-star-mass-sun-record-black-holes, 2022-07-25, Science News, en-US, JOURNAL, Romani, Roger W., Kandel, D., Filippenko, Alexei V., Brink, Thomas G., Zheng, WeiKang, 2022-07-11, PSR J0952â0607: The Fastest and Heaviest Known Galactic Neutron Star, The Astrophysical Journal Letters, 934, 2, L17, 10.3847/2041-8213/ac8007, 2207.05124, 2022ApJ...934L..17R, 250451299, free,
- PSR J1903+0327, a ~2.15 ms pulsar discovered to be in a highly eccentric binary star system with a Sun-like star.JOURNAL, Champion, David J., An Eccentric Binary Millisecond Pulsar in the Galactic Plane, Science, 2008, 320, 5881, 18483399, 1309â1312, 10.1126/science.1157580, 2008Sci...320.1309C, 0805.2396, Ransom, S. M., Lazarus, P., Camilo, F., Bassa, C., Kaspi, V. M., Nice, D. J., Freire, P. C. C., Stairs, I. H., Van Leeuwen, J., Stappers, B. W., Cordes, J. M., Hessels, J. W. T., Lorimer, D. R., Arzoumanian, Z., Backer, D. C., Bhat, N. D. R., Chatterjee, S., Cognard, I., Deneva, J. S., Faucher-Giguere, C.-A., Gaensler, B. M., Han, J., Jenet, F. A., Kasian, L., Kondratiev, V. I., Kramer, M., Lazio, J., McLaughlin, M. A., Venkataraman, A., 6070830, 29,
- PSR J2007+2722, a 40.8-hertz ‘recycled’ isolated pulsar was the first pulsar found by volunteers on data taken in February 2007 and analyzed by distributed computing project Einstein@Home.JOURNAL, B., Knispel, Allen, B, 2010, Cordes, JM, Deneva, JS, Anderson, D, Aulbert, C, Bhat, ND, Bock, O, Bogdanov, S, Brazier, A., Camilo, F., Champion, D. J., Chatterjee, S., Crawford, F., Demorest, P. B., Fehrmann, H., Freire, P. C. C., Gonzalez, M. E., Hammer, D., Hessels, J. W. T., Jenet, F. A., Kasian, L., Kaspi, V. M., Kramer, M., Lazarus, P., Van Leeuwen, J., Lorimer, D. R., Lyne, A. G., Machenschalk, B., McLaughlin, M. A., Pulsar Discovery by Global Volunteer Computing, Science, 20705813, 329, 5997, 1305, 10.1126/science.1195253, 2010Sci...329.1305K, 1008.2172, 29786670, 8,
- PSR J1311â3430, the first millisecond pulsar discovered via gamma-ray pulsations and part of a binary system with the shortest orbital period.JOURNAL, H. J., Pletsch, Guillemot, 2012, Science, 10.1126/science.1229054, 1211.1385, 2012Sci...338.1314P, 23112297, 338, 6112, Binary millisecond pulsar discovery via gamma-ray pulsations, 1314â1317, Fehrmann, H., Allen, B., Kramer, M., Aulbert, C., Ackermann, M., Ajello, M., De Angelis, A., Atwood, W. B., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Borgland, A. W., Bottacini, E., Brandt, T. J., Bregeon, J., Brigida, M., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Patrizia A. Caraveo, Casandjian, J. M., Cecchi, C., Ãelik, Ã., 206544680, 29,
Gallery
Image:Crab Lucky video2.gif|Video â Crab Pulsar â bright pulse and interpulse.Image:Vela Pulsar jet seen by Chandra Observatory.ogv|Video â Vela pulsar â X-ray light.Image:Artist’s impression video of the exotic binary star system AR Scorpii (video).webm|Video â Artist’s impression of AR Scorpii.See also
{hide}columns-list|colwidth=22em|- Anomalous X-ray pulsar
- Black hole
- Double pulsar
- Magnetar
- Neutron star
- Optical pulsar
- Pulsar clock
- Pulsar planet
- Pulsar timing array
- Pulsar wind nebula
- Radio astronomy
- Radio star
- Rotating radio transient
- Soft gamma repeater
- Supernova remnant
- X-ray pulsar
References
Further reading
- BOOK, Lorimer, Duncan R., Kramer, Michael, Handbook of Pulsar Astronomy, 2004, Cambridge University Press, 978-0-521-82823-9,books.google.com/books?id=OZ8tdN6qJcsC, Lorimer2004,
- JOURNAL
, Lorimer, Duncan R.
,relativity.livingreviews.org/Articles/lrr-2008-8/
, Binary and Millisecond Pulsars
, Living Reviews in Relativity
, 2008
, 11
, 1
, 8
, 10.12942/lrr-2008-8
, 28179824
, 5256074
, 0811.0762
, 2008LRR....11....8L
, Lorimer2008
, 2011-12-14
,relativity.livingreviews.org/Articles/lrr-2008-8/" title="web.archive.org/web/20120315040749relativity.livingreviews.org/Articles/lrr-2008-8/">web.archive.org/web/20120315040749relativity.livingreviews.org/Articles/lrr-2008-8/
, 2012-03-15
, dead
, ,relativity.livingreviews.org/Articles/lrr-2008-8/
, Binary and Millisecond Pulsars
, Living Reviews in Relativity
, 2008
, 11
, 1
, 8
, 10.12942/lrr-2008-8
, 28179824
, 5256074
, 0811.0762
, 2008LRR....11....8L
, Lorimer2008
, 2011-12-14
,relativity.livingreviews.org/Articles/lrr-2008-8/" title="web.archive.org/web/20120315040749relativity.livingreviews.org/Articles/lrr-2008-8/">web.archive.org/web/20120315040749relativity.livingreviews.org/Articles/lrr-2008-8/
, 2012-03-15
, dead
- BOOK, Lyne, Andrew G., Graham-Smith, Francis, Pulsar Astronomy, Cambridge University Press, 1998, 978-0-521-59413-4
books.google.com/books?id=AK9N3zxL4ToC>ref= Lyne1998, - BOOK, Pulsars, Manchester, Richard N., Taylor, Joseph H., 1977, W. H. Freeman and Company, 978-0-7167-0358-7
archive.org/details/pulsars0000manc> url-access = registration, Manchester1977, - JOURNAL, Stairs, Ingrid H, Testing General Relativity with Pulsar Timing, Living Reviews in Relativity, 6, 1, 5
ref= Stairs2003, 10.12942/lrr-2003-5, 28163640, 5253800, 2003LRR.....6....5S, astro-ph/0307536, External links
{{Commons category|Pulsars}}- “A Pulsar Discovery: First Optical Pulsar {{Webarchive|url=https://web.archive.org/web/20071003093545www.aip.org/history/mod/ |date=2007-10-03 }}”. Moments of Discovery, American Institute of Physics, 2007 (Includes audio and teachers guides).
- Discovery of Pulsars: Interview with Jocelyn Bell Burnell. Jodcast, June 2007 (Low Quality Version).
- Audio: Cain/Gay â Astronomy Cast. Pulsars â Nov 2009
- Australia National Telescope Facility: Pulsar Catalogue
- Johnston, William Robert. “List of Pulsars in Binary Systems”. Johnston Archive, 22 March 2005.
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