PSR J0437-4715

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PSR J0437-4715 is a pulsar. Discovered in the Parkes 70 cm survey,[1] it remains the closest and brightest millisecond pulsar (MSP) known. The pulsar rotates about its axis 173.7 times per second and therefore completes a rotation every 5.75 milliseconds. It emits a searchlight-like radio beam that sweeps past the Earth each time it rotates. Currently the most precisely located object outside of our Solar System, PSR J0437-4715 is 156.3 parsecs or 509.8 light years distant.[2]

This pulsar is distinguished by being the most stable natural clock known and is debatably more stable than man-made atomic clocks.[3][4] Its stability is about one part in 1015. Two other pulsars, PSR B1855+09 and PSR B1937+21 are known to be comparable in stability to atomic clocks, or about 3 parts in 1014.

PSR J0437-4715 is the first MSP to have its X-ray emission detected and studied in detail.[5] It is also the first of only two pulsars to have the full three-dimensional orientation of its orbit determined.[6]

Optical observations indicate that the binary companion of PSR J0437-4715 is most likely a low-mass helium white dwarf.[7] The pulsar is about 1.8 solar mass and the companion is about 0.25 solar masses.[8] The pair revolve around each other every 5.75 days in nearly perfect circular orbits.[9]

See also[edit]


  1. ^ Johnston, Simon; Lorimer, D. R.; Harrison, P. A.; Bailes, M.; Lynet, A. G.; Bell, J. F.; Kaspi, V. M.; Manchester, R. N. et al. (1993). "Discovery of a very bright, nearby binary millisecond pulsar". Nature 361 (6413): 613–615. Bibcode:1993Natur.361..613J. doi:10.1038/361613a0. 
  2. ^ Deller, A. T.; Verbiest, J. P. W.; Tingay, S. J.; Bailes, M. (2008). "Extremely High Precision VLBI Astrometry of PSR J0437-4715 and Implications for Theories of Gravity". The Astrophysical Journal 685: L67. arXiv:0808.1594. Bibcode:2008ApJ...685L..67D. doi:10.1086/592401. 
  3. ^ Timing stability
  4. ^ Hartnett, J. G.; Luiten, A. N. (2011). "Colloquium: Comparison of astrophysical and terrestrial frequency standards". Reviews of Modern Physics 83: 1. doi:10.1103/RevModPhys.83.1.  edit
  5. ^ Becker, Werner; Trümper, Joachim (1993). "Detection of pulsed X-rays from the binary millisecond pulsar J0437 - 4715". Nature 365 (6446): 528. Bibcode:1993Natur.365..528B. doi:10.1038/365528a0. 
  6. ^ Van Straten, W.; Bailes, M.; Britton, M.; Kulkarni, S. R,; Anderson, S. B.; Manchester, R. N.; Sarkissian, J. (2001). "A test of general relativity from the three-dimensional orbital geometry of a binary pulsar". Nature 412 (6843): 158–160. arXiv:astro-ph/0108254. Bibcode:2001Natur.412..158V. doi:10.1038/35084015. PMID 11449265. 
  7. ^ Bell, J. F.; Bailes, M.; Bessell, M. S. (1993). "Optical detection of the companion of the millisecond pulsar J0437–4715". Nature 364 (6438): 603. doi:10.1038/364603a0.  edit
  8. ^ Verbiest, J. P. W.; Bailes, M.; van Straten, W.; Hobbs, G. B.; Edwards, R. T.; Manchester, R. N.; Bhat, N. D. R.; Sarkissian, J. M.; Jacoby, B. A.; Kulkarni, S. R. (2008). "Precision Timing of PSR J0437-4715: An Accurate Pulsar Distance, a High Pulsar Mass, and a Limit on the Variation of Newton's Gravitational Constant". The Astrophysical Journal 679: 675. arXiv:0801.2589. Bibcode:2008ApJ...679..675V. doi:10.1086/529576. 
  9. ^ Tables of Binary and Millisecond Pulsars