PSR J0437−4715

{{Short description|Pulsar in the constellation Pictor}}

{{Starbox begin |

name=PSR J0437−4715}}

{{Starbox observe

|epoch=J2000

|ra={{RA|04|37|15.81476}}

|dec={{DEC|−47|15|08.6242}}

|constell=Pictor

|appmag_v={{val|20.98|0.09}}}}

{{Starbox character

|class=Pulsar }}

{{Starbox astrometry

|prop_mo_ra=121.453

|prop_mo_dec=71.457

|dist_ly=509.8

|dist_pc=156.3

}}

{{Starbox detail

|mass=1.44 }}

{{Starbox catalog

|names=PSR B0435−47, 1RXS J043714.5−471503}}

{{Starbox reference

|Simbad=PSR+J0437−4715}}

{{Starbox end}}

PSR J0437−4715 is a pulsar. Discovered in the Parkes 70 cm survey,{{cite journal | doi = 10.1038/361613a0 | title = Discovery of a very bright, nearby binary millisecond pulsar | date = 1993 | last1 = Johnston | first1 = Simon | last2 = Lorimer | first2 = D. R. | last3 = Harrison | first3 = P. A. | last4 = Bailes | first4 = M. | last5 = Lynet | first5 = A. G. | last6 = Bell | first6 = J. F. | last7 = Kaspi | first7 = V. M. | last8 = Manchester | first8 = R. N. | last9 = D'amico | first9 = N. | last10 = Nleastrol | first10 = L. | last11 = Shengzhen | first11 = Jin | journal = Nature | volume = 361 | issue = 6413 | pages = 613–615 | bibcode = 1993Natur.361..613J | s2cid = 4324763 | display-authors = 8 }} 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. Until the Gaia mission, it was the most precisely located object outside of the Solar System, recorded in 2008 at {{val|156.3|1.3}} parsecs or {{val|509.8|4.2}} light-years distant.{{cite journal| bibcode = 2008ApJ...685L..67D| title = Extremely High Precision VLBI Astrometry of PSR J0437-4715 and Implications for Theories of Gravity| author1 = Deller, A. T.| author2 = Verbiest, J. P. W.| author3 = Tingay, S. J.| author4 = Bailes, M.| volume = 685| date = 2008| pages = L67–L70| journal = The Astrophysical Journal| issue = 1| doi = 10.1086/592401 |arxiv = 0808.1594 | s2cid = 8362572}}

This pulsar is distinguished by being the most stable natural clock known and is debatably more stable than man-made atomic clocks.{{cite web|url=http://relativity.livingreviews.org/Articles/lrr-2005-7/articlesu18.html#x25-370004.3|title=Timing stability|access-date=2009-05-09|archive-url=https://web.archive.org/web/20160305192438/http://relativity.livingreviews.org/Articles/lrr-2005-7/articlesu18.html#x25-370004.3|archive-date=2016-03-05|url-status=dead}}{{Cite journal | last1 = Hartnett | first1 = J. G. | last2 = Luiten | first2 = A. N. | doi = 10.1103/RevModPhys.83.1 | title = Colloquium: Comparison of astrophysical and terrestrial frequency standards | journal = Reviews of Modern Physics | volume = 83 | pages = 1–9 | year = 2011 | issue = 1 |arxiv = 1004.0115 |bibcode = 2011RvMP...83....1H | s2cid = 118396798 }} 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.{{cite journal | bibcode = 1993Natur.365..528B | title = Detection of pulsed X-rays from the binary millisecond pulsar J0437 - 4715 | author1 = Becker, Werner | author2 = Trümper, Joachim | volume = 365 | date = 1993 | pages = 528 | journal = Nature | doi = 10.1038/365528a0 | issue = 6446 | s2cid = 4342134 }} It is also the first of only two pulsars to have the full three-dimensional orientation of its orbit determined.{{cite journal | doi = 10.1038/35084015 | date = 2001 | last1 = Van Straten | first1 = W. | display-authors = 4 | last2 = Bailes | first2 = M. | last3 = Britton | first3 = M. | last4 = Kulkarni | first4 = S. R. | last5 = Anderson | first5 = S. B. | last6 = Manchester | first6 = R. N. | last7 = Sarkissian | first7 = J. | journal = Nature | volume = 412 | issue = 6843 | pages = 158–160 | pmid = 11449265 | title = A test of general relativity from the three-dimensional orbital geometry of a binary pulsar | bibcode = 2001Natur.412..158V |arxiv = astro-ph/0108254 | s2cid = 4363384 }}

Optical observations indicate that the binary companion of PSR J0437-4715 is most likely a low-mass helium white dwarf.{{Cite journal | last1 = Bell | first1 = J. F. | last2 = Bailes | first2 = M. | last3 = Bessell | first3 = M. S. | doi = 10.1038/364603a0 | title = Optical detection of the companion of the millisecond pulsar J0437–4715 | journal = Nature | volume = 364 | issue = 6438 | pages = 603 | year = 1993 |bibcode = 1993Natur.364..603B | s2cid = 44962125 }}

The pulsar is about 1.4 solar mass ({{Solar mass|link=y}}){{cite journal | bibcode = 2016MNRAS.455.1751R | title = Timing analysis for 20 millisecond pulsars in the Parkes Pulsar Timing Array | author1 = Reardon, D. J. | display-authors = 4 | author2 = Hobbs, G. | author3 = Coles, W. | author4 = Levin, Y. | volume = 455 | date = 2016 | pages = 1751–1769 | journal = Monthly Notices of the Royal Astronomical Society | doi = 10.1093/mnras/stv2395 |arxiv = 1510.04434 | last5 = Keith | first5 = M. J. | issue = 2 | doi-access = free }} and the companion is about 0.25 {{Solar mass}}.{{cite journal | bibcode = 2008ApJ...679..675V | title = 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 | author1 = Verbiest, J. P. W. | display-authors = 4 | author2 = Bailes, M. | author3 = van Straten, W. | author4 = Hobbs, G. B. | author5 = Edwards, R. T. | author6 = Manchester, R. N. | author7 = Bhat, N. D. R. | author8 = Sarkissian, J. M. | author9 = Jacoby, B. A. | volume = 679 | date = 2008 | pages = 675 | journal = The Astrophysical Journal | doi = 10.1086/529576 |arxiv = 0801.2589 | last10 = Kulkarni | first10 = S. R. | issue = 1 | s2cid = 5207918 }} The pair revolve around each other every 5.75 days in nearly perfect circular orbits.{{cite web|url=http://relativity.livingreviews.org/Articles/lrr-2005-7/articlese7.html|title=Tables of Binary and Millisecond Pulsars|access-date=2009-05-09|archive-url=https://web.archive.org/web/20160303194208/http://relativity.livingreviews.org/Articles/lrr-2005-7/articlese7.html|archive-date=2016-03-03|url-status=dead}}