What is Pulsars: Definition and 31 Discussions

A pulsar (from Pulsating Radio Sources) is a highly magnetized rotating compact star (usually neutron stars but also white dwarfs) that emits beams of electromagnetic radiation out of its magnetic poles. 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 around a pulsar, PSR B1257+12. In 1983, certain types of pulsars were detected that at that time exceeded the accuracy of atomic clocks in keeping time.

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  1. zinn

    I Separation angle between pulsars detecting Gravitational Waves

    I’m trying to understand the Hellings and Downs curve that is being used to argue for the existence of a gravitational wave background ([NANOGrav article][1]). How can it be that the angle between two pulsars is the only variable that determines if the gravitational waves will interfere...
  2. Astronuc

    B Vulpecula, pulsars and neutron stars

    I was listening to a Star Date podcast regarding the constellation Vulpecula and learned about the discovery of pulsars and neutron stars. https://stardate.org/radio/program/2023-03-19 The first neutron star was discovered in Vulpecula in 1967. https://en.wikipedia.org/wiki/PSR_B1919+21 In...
  3. S

    I Are there more Pulsars than we observe?

    Hello All Dame Jocelyn Bell Burnell (the lady who was robbed of the Nobel Prize) described Pulsars to be like lighthouses, emitting a beam of high intensity light modulated by their spin, which we see as they 'flash' towards us. Would we only see the beam as pulses if the Pulsar was spinning...
  4. A

    Question about the radiation around Neutron Stars or Pulsars

    I have a sci-fi idea regarding being able to move planets around like billiard balls. I'm theorizing that, after a nova, some of the bands of material around a star formed a new ring of rocky planets around a Neutron Star. Naturally, these are bathed in radiation. Having never taken high...
  5. T

    Stargazing New Radio Telescope is World's Largest

    World's largest radiotelescope just completed. http://news.xinhuanet.com/english/2016-07/03/c_135485643.htm
  6. Elbert Anstein

    B Pulsars and Neutron Stars debunked?

    Now kindly pardon my ignorance but I hope one of you can explain to me how this can be possible. A rotating neutron star or pulsar have been observed to spin at between 10 to 700 times per second. Now before I proceed further I like to draw your memories back to the merry go round we played as...
  7. R

    B How is the characteristic age of pulsars typically calculated?

    Hi everyone. I'm trying to derive the formula for the characteristic age of a pulsar. What I'm starting with is the following differential equation. dP/dt=K*P2-n What i think is odd, is several places they say solving this differential equation gives the following solution...
  8. R

    Why do pulsars emit radiation from both poles?

    Hi everyone, The charged particles in the magnetic field around the neuton star, is accelerated along the magnetic field lines, which would go in a curve, from the north pole to the south pole. Due to the acceleration the particles will emit radiation, along their movement axis, and because the...
  9. R

    Data from pulsars - light curves?

    Hi everybody, I hope some of you have worked with pulsars before or other x-ray data from NASA Heasarc. I need some data showing a very precise light curve of the crab pulsar and some other pulsar. It should be something like this: http://cdn.eso.org/images/screen/eso9948i.jpg Where the time...
  10. 24forChromium

    Why do pulsars emit electromagnetic waves from their poles?

    Is this phenomenon explicable with the simple laws of electromagnetism alone?
  11. Stephanus

    What information can be derived from the pulsars featured on the Voyager plate?

    Dear PF Forum, I've read the current Featured Thread in November 12nd, Lost in the Milky Way scenario. It's a good thread. But I want know what pulsar is. https://en.wikipedia.org/wiki/Pulsar A. Does pulsar(s) have unique frequency? Given the number of pulsar in our galaxy and the vast range of...
  12. J

    Period of radial oscillations

    Assuming a neutron star is a uniformly dense sphere of radius 10km and mass =1.4 mass of sun, derive the period of radial oscillations.First use hydrostatic equilibrium to calculate p, then the velocity of sound is $$v= \sqrt{ \gamma p / \rho}$$, so the period of pulsation is time it takes from...
  13. Alex299792458

    Do neutron stars, pulsars, magnetars etc. have weather?

    Do neutron star, pulsars, magnetars etc. have solar flares like the sun or do they have sun spots like the sun or do they have solar winds and if they do have any of those types of weather, what are they called?
  14. S

    Exploring Sounds of Pulsars & Beyond

    I'm slightly confused as to why and how we record "sounds" from space using radio-waves. Take for example, objects like pulsars on this website: http://www.jb.man.ac.uk/pulsar/Education/Sounds/ So do pulsars really sound like this? Do they actually produce a knocking/ticking sound? Or are these...
  15. D

    Creation of spinning neutron stars and pulsars

    I've gotten a bit confused about the creation of the neutron star/pulsar, so I was hoping someone could point me in the right direction :) As fusion stops, when reaching the iron phase, the outer layers (hydrogen, helium, carbon... etc.) gets pulled in-wards do to gravity. This creates a bounce...
  16. shounakbhatta

    Pulsars - Rotating neutron star produces EM radiation?

    Pulsars -- Rotating neutron star produces EM radiation? Hello, If a neutron star is composed of neutrons, which do not carry any electric charge then how it's rotation produces pulsars which are electromagnetic radiation? Thanks.
  17. A

    How does Angular Momentum relate to the rapid rotation of Pulsars?

    Hello, Does the Conservation of Angular Momentum have any relation to the rapid rotation of Pulsars? I've reasoned that the Angular Momentum of the "parent" star would be concentrated on the smaller pulsar and would produce a greater frequency of rotation. Thanks,
  18. R

    What Causes the Beamed Emission of Pulsars?

    Hello everybody. I am searching for an explanation about the beamed emission of pulsars, either in radio and in X-rays bands. I can not find a "standard" reason (with demonstration, eventually) for the beaming of this objects' radiation. Please, can you suggest to me something, or even a link...
  19. T

    Is there a limit on the rotational speed of fast spinning pulsars?

    And if so, what is the limit? Some pulsars spin very fast. more than 700 times per second, or even faster? So the centrifugal force would be very strong at the equator, threatening to rip them apart. Is there a limit on how fast a pulsar can spin before the centrifugal force would...
  20. L

    Pulsars: fluctuating speed of rotation?

    Please excuse the lay question; I'm not an astrophysicist nor do I study it accademically, but it interests me is all. I have a question about pulsars that I've tried to research via google, but the results I'm getting are very heavy, accademic texts. So, I'm hoping someone here could...
  21. S

    Do all pulsars have a Pulsar wind nebula?

    Intuitively I would say no because it seems like a big call but at the same time the high energy effects rely on the interaction between magnetic fields and gas don't they? Any tips or just an idea of where I can find out would be awesome
  22. A

    Pulsars (but really calculus)

    looking at my notes on pulsars I have: K=\frac{2\pi^{2}I}{P^{2}}\implies dk=\frac{2\pi^{2}I}{P^{2}}dP\implies\frac{dk}{dt}=\frac{-4\pi^{2}I}{P^{3}}\frac{dP}{dt} where K is kinetic rotational energy and P is momentum... I don't quite follow the final expression (when the time derivitive...
  23. B

    Can someone explain Pulsars and Quasars?

    I know that pulsars are Neutron stars that emit their energy through their poles, bit why do they emit it through their poles, and not their sides? And Quasars, I though that all mater that falls into a black hole never escapes, so how do we see the...''stuff'' leaving it?
  24. N

    Read article on Pulsars, not clear how a sphere sources pole-only emission?

    The pole still has extremely strong gravity, how can a sphere suddenly concentrate the radiation at the pole to be emitted there ? As this is the only exit, should there not be a strong deformation ? How does the radiation make it to the pole, or, is the radiation we are getting only from...
  25. Garth

    Pliers, pulsars and extreme physics

    Ever wondered what it is like to make a major discovery in astrophysics? You may be interested in reading Jocelyn Bell Burnell's account of how she discovered pulsars as a postgraduate: http://www3.interscience.wiley.com/cgi-bin/fulltext/118807400/PDFSTART. BTW, - Jocelyn is too gracious to...
  26. A

    Pulsars vs. Brown Dwarves & Blue Giants: A Celestial Q&A

    Ok two questions for all u smart people out there: 1. What is the difference between a pulsar and a brown dwarf? are brown dwarves just dead white dwarves? 2. M45. A cluster of blue giants in the sky. Are they actually close relative to each other like our sun and Sirius or Alpha Centauri...
  27. N

    USAF 'discovered' pulsars long before Bell Burnell

    ...but they just didn't call it such. :rolleyes: Interesting story: http://scienceblogs.com/catdynamics/2007/08/schisler.php
  28. MathematicalPhysicist

    Pulsars with irregular periodicity radiation

    have such stars been observed by the astrophysicists? and if they haven't yet, are they predicted by the current model of neutron stars physics and evolution?
  29. V

    Binary pulsars and general relativity

    hi just wondering if anyone knows some interesting things about binary pulsars in relation to general relativity. i have to give a short presentation on the topic and need some ideas on what to talk about thanks in advance
  30. Norman

    Interstellar Medium and Pulsars

    Originally posted in College Level Homework help but I got no responses there. Please help if you can. I am studying for my qualifier and doing problems out of Jackson. I am stuck on this one... any help would really be appreciated... I am unsure how to begin: Jackson 7.15 The partially...
  31. wolram

    Nanosecond Pulsars: Gauging Universe Expansion

    why can't we use nanosecond pulsars to gauge expansion of universe? even if they are irregular ,if the "tendancy "of pulses measured in a second is always downward then at least it would be a partial proof.
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