What is the fastest spinning rotation of a Neutron star? I have heard that Neutron stars have a specially fast spinning rotation. What is the fastest?


2 Answers 2


As it turns out, the fastest spinning neutron star found yet is a pulsar 18000 light years away in the constelation of Sagittarius which scientist catalogued as PSR J1748-2446ad. Pulsars are neutron stars that rotate, are highly magnetic and emit a strong perpendicular beam of electromagnetic radiation.

This pulsar's speed is such that:

At its equator it is spinning at approximately 24% of the speed of light, or over 70,000 km per second.

PSR J1748-2446ad rotates a little over 700 times a second, and scientists have this to say on the theoretical limits of the rotation speed of a pulsar (from here):

Current theories of neutron star structure and evolution predict that pulsars would break apart if they spun at a rate of ~1500 rotations per second or more, and that at a rate of above about 1000 rotations per second they would lose energy by gravitational radiation faster than the accretion process would speed them up.

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    $\begingroup$ Fun experiment. Go here meettechniek.info/additional/additive-synthesis.html select Impuls, type the number 716 in the Sound Frequency field, and raise the volume. The sound you're hearing is the rotation frequency of the pulsar PSR J1748-2446ad. $\endgroup$ Commented Sep 8, 2017 at 17:57
  • $\begingroup$ Wow, that also means that such an ultrafast rotating NS is essentially a kinetic energy -> gravitational wave converter. $\endgroup$
    – peterh
    Commented Mar 3, 2022 at 22:43

The fastest celestial body we know so far is neutron star XTE J1739-285. It rotates 1122 times per second. Source: https://arxiv.org/abs/0712.4310?fbclid=IwAR2g9RYhybbBlxxzKOfquBa9C33H8mMwuZ_mHZbm1RbcsetrxO3vbvXq7gA

  • $\begingroup$ Chakrabarty (2008) reports that the measurement of the sub-millisecond spin is marginal. Furthermore Drago et al. (2008) suggest that such an object would have to be a quark star or a hybrid quark-hadron star. $\endgroup$
    – user24157
    Commented Jan 28, 2019 at 20:51

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