Editing PSR J0737−3039

{{Use mdy dates|date=June 2022|cs1-dates=l}}
{{short description|Double pulsar in the constellation Puppis}}
{{Redir|Double pulsar|the general topic on double pulsars|binary pulsar|the NSA backdoor exploit toolkit|DoublePulsar}}

{{Starbox begin}}
{{Starbox image
| image = [[Image:J0737-3039 still1 large.jpg|250px]]
| caption = Artist's impression.  The objects are not shown to scale: if they were depicted as the size of [[Marble (toy)|marbles]], they would be 225 [[metre|m]] (750 [[foot (length)|ft]]) apart. See also [http://www.jb.man.ac.uk/news/doublepulsar/p0738_2.mpg MPEG animation] (2.4 [[megabyte|MB]]) }}
{{Starbox observe
| epoch=J2000
| ra={{RA|07|37|51.248}}
| dec={{DEC|-30|39|40.83}}
| appmag_v=
| constell=[[Puppis]] }}
{{Starbox character
| class=Pulsar
| b-v=
| u-b=
| variable=None }}
{{Starbox astrometry
| radial_v=
| prop_mo_ra=
| prop_mo_dec=
| parallax=
| p_error=
| absmag_v=
| dist_ly=3200–4500
| dist_pc=1150
}}
{{Starbox orbit
| reference = <ref>{{citation|arxiv=2011.02357|title=Understanding and improving the timing of PSR J0737−3039B|year=2020|doi=10.1051/0004-6361/202038566|last1=Noutsos|first1=A.|last2=Desvignes|first2=G.|last3=Kramer|first3=M.|last4=Wex|first4=N.|last5=Freire|first5=P. C. C.|last6=Stairs|first6=I. H.|last7=McLaughlin|first7=M. A.|last8=Manchester|first8=R. N.|last9=Possenti|first9=A.|last10=Burgay|first10=M.|last11=Lyne|first11=A. G.|last12=Breton|first12=R. P.|last13=Perera|first13=B. B. P.|last14=Ferdman|first14=R. D.|journal=Astronomy & Astrophysics|volume=643|pages=A143|bibcode=2020A&A...643A.143N|s2cid=224991311}}</ref>
| primary = PSR J0737−3039 A
| name = PSR J0737−3039 B
| period = <!--Period (in years)-->
| period_unitless = 2.45 [[hour|h]]
| axis = <!--Semimajor axis (in arcseconds)-->
| axis_unitless = <!--Semimajor axis (no units provided by template)-->
| eccentricity = 0.088
| inclination = <!--Inclination (in degrees)-->
| node = <!--Longitude of node (in degrees)-->
| periastron = <!--Periastron epoch-->
| periarg = <!--Argument of periastron (in degrees), secondary -->
| periarg_primary = <!--Argument of periastron (in degrees), primary -->
| k1 = <!-- Velocity semi-amplitude (SB1, or primary in SB2), in km/s -->
| k2 = <!-- Velocity semi-amplitude (secondary in SB2), in km/s -->
}}
{{Starbox detail
| component1=PSR J0737−3039A
| mass=1.338
| radius=
| luminosity=
| temperature=
| metal=
| rotation={{#expr:22.6993785996239 + 1.75993e-15 * ({{#time:U}} - 86400 * (53156.0 - 40587)) round 12}} [[millisecond|ms]]<ref name=firstdp>[http://www.atnf.csiro.au/research/highlights/2003/manchester/manchester.html atnf The first double pulsar - List of the team]. Retrieved 2010-07-07</ref><ref name=atnf>[http://www.atnf.csiro.au/research/pulsar/psrcat/ ATNF Pulsar Catalogue] database [http://www.atnf.csiro.au/research/pulsar/psrcat/proc_form.php?version=1.54&startUserDefined=true&sort_attr=jname&sort_order=asc&pulsar_names=J0737-3039*&ephemeris=long&submit_ephemeris=Get+Ephemeris&coords_unit=raj%2Fdecj&style=Long+with+last+digit+error&no_value=*&fsize=3&x_scale=linear&y_scale=linear&state=query].</ref>
| age=
| component2=PSR J0737−3039B
| mass2=1.249
| mutual orbit2= e=0.09
| rotation2={{#expr:2.77346077007 + 8.92e-16 * ({{#time:U}} - 86400 * (53156.0 - 40587)) round 10}} [[second|s]]<ref name=firstdp /><ref name=atnf />
}}
{{Starbox catalog
| names=2XMM J073751.4−303940
}}
{{Starbox reference
| Simbad=PSR+J0737−3039
}}
{{Starbox end}}

'''PSR J0737−3039''' is the first known double [[pulsar]]. It consists of two [[neutron star]]s emitting [[Electromagnetic radiation|electromagnetic waves]] in the radio wavelength in a relativistic [[binary system]]. The two pulsars are known as PSR J0737−3039A and PSR J0737−3039B. It was discovered in 2003 at [[Australia]]'s [[Parkes Observatory]] by an international team led by the Italian radio astronomer [[Marta Burgay]] during a high-latitude pulsar survey.<ref>{{Cite journal |last1=Burgay |first1=M. |last2=d'Amico |first2=N. |last3=Possenti |first3=A. |last4=Manchester |first4=R. N. |last5=Lyne |first5=A. G. |last6=Joshi |first6=B. C. |last7=McLaughlin |first7=M. A. |last8=Kramer |first8=M. |last9=Sarkissian |first9=J. M. |last10=Camilo |first10=F. |last11=Kalogera |first11=V. |display-authors=2 |date=4 December 2003 |title=An increased estimate of the merger rate of double neutron stars from observations of a highly relativistic system |url=https://www.nature.com/articles/nature02124 |journal=Nature |volume=426 |issue=6966 |pages=531–533 |arxiv=astro-ph/0312071 |bibcode=2003Natur.426..531B |doi=10.1038/nature02124 |pmid=14654834 |last12=Kim |first12=C. |last13=Lorimer |first13=D. R. |s2cid=4336133}}</ref>

== Pulsars ==
A pulsar is a [[neutron star]] which produces pulsating radio emission due to a strong [[magnetic field]].  A neutron star is the ultra-compact remnant of a massive star which exploded as a [[supernova]].  Neutron stars have a mass bigger than the [[Sun]], yet are only a few kilometers across. These extremely dense objects rotate on their [[Rotation around a fixed axis|axes]], producing focused [[electromagnetic waves]] which sweep around the sky and briefly point toward Earth in a lighthouse effect at rates that can reach a few hundred pulses per second.

Although double neutron star systems were known before its discovery, PSR J0737−3039 is the first and only known system ({{asof|2021|lc=y}}) where both neutron stars are pulsars&nbsp;– hence, a "double pulsar" system.<ref name="Silva2021"/>  The object is similar to [[PSR B1913+16]], which was discovered in 1974 by Jocelyn Bell, [[Joseph Hooton Taylor Jr.|Taylor]] and [[Russell Alan Hulse|Hulse]], and for which the two won the 1993 [[Nobel Prize in Physics]]. Objects of this kind enable precise testing of [[Albert Einstein|Einstein]]'s theory of [[general relativity]], because the precise and consistent timing of the pulsar pulses allows relativistic effects to be seen when they would otherwise be too small.  While many known pulsars have a binary companion, and many of those are believed to be neutron stars, J0737−3039 is the first case where both components are known to be not just neutron stars but pulsars.

===Discovery===
PSR J0737−3039A was discovered in 2003, along with its partner, at Australia's 64&nbsp;m antenna of the [[Parkes Observatory|Parkes Radio Observatory]];  J0737−3039B was not identified as a pulsar until a second observation. The system was originally observed by an international team during a high-latitude multibeam survey organized in order to discover more pulsars in the night sky.<ref name="firstdp" />

Initially, this [[star system]] was thought to be an ordinary pulsar detection. The first detection showed one pulsar with a period of 23 milliseconds in orbit around a neutron star. Only after follow up observations was a weaker second pulsar detected with a pulse of 2.8 seconds from the companion star.

== Physical characteristics ==
The orbital period of J0737−3039 (2.4 hours) is one of the shortest known for such an object (one-third that of the [[PSR B1913+16|Taylor–Hulse binary]]), which enables the most precise tests yet. In 2005, it was announced that measurements had shown an excellent agreement between general relativity theory and observation.  In particular, the predictions for energy loss due to [[gravitational wave]]s appear to match the theory.

As a result of energy loss due to gravitational waves, the common orbit (roughly {{Convert|800,000|km|mi|abbr=off|sp=us|disp=sqbr}} in diameter) shrinks by 7 mm per day. The two components will coalesce in about 85 million years.
:{| class=wikitable
|-
! align="left" | Property
! align="left" | Pulsar A
! align="left" | Pulsar B
|-
! Spin period
| 22.699 milliseconds
| 2.773 seconds
|-
! Mass
| 1.337 solar masses
| 1.250 solar masses
|-
! Orbital period
| colspan="2" align="center" | 2.454 hours (8834.53499 seconds)
|-
|}

Due to relativistic spin precession, the pulses from Pulsar B are no longer detectable {{As of|2008|March|lc=y}} but are expected to reappear in 2035 due to precession back into view.<ref>{{Cite journal |last1=Perera |first1=B. B. P. |last2=McLaughlin |first2=M. A. |last3=Kramer |first3=M. |last4=Stairs |first4=I. H. |last5=Ferdman |first5=R. D. |last6=Freire |first6=P. C. C. |last7=Possenti |first7=A. |last8=Breton |first8=R. P. |last9=Manchester |first9=R. N. |last10=Burgay |first10=M. |last11=Lyne |first11=A. G. |display-authors=2 |year=2010 |title=The Evolution of PSR J0737−3039B and a Model for Relativistic Spin Precession |url=https://iopscience.iop.org/article/10.1088/0004-637X/721/2/1193 |journal=[[The Astrophysical Journal]] |volume=721 |issue=2 |pages=1193–1205 |arxiv=1008.1097 |bibcode=2010ApJ...721.1193P |doi=10.1088/0004-637X/721/2/1193 |last12=Camilo |first12=F. |s2cid=118854647}}</ref>

== Use as a test of general relativity ==
{{See also|Hulse–Taylor binary#Use as a test of general relativity}}

[[File:PSRJ0737−3039shift2021.png|thumb|upright=0.75|Cumulative shift in the periastron period]]

Observations of 16 years of timing data have been reported in 2021 to be on agreement with general relativity by studying the loss of orbital energy due to [[Gravitational wave|gravitational waves]]. The [[orbital decay]] and the speedup of the [[orbital period]] was tested to follow the [[quadrupole formula]] with a great precision of 0.013% mainly because of the unique characteristics of the system which has two pulsars, is nearby and possesses an inclination close to 90°.<ref>{{Cite journal |last1=Kramer |first1=M. |last2=Stairs |first2=I. H. |last3=Manchester |first3=R. N. |last4=Wex |first4=N. |last5=Deller |first5=A. T. |last6=Coles |first6=W. A. |last7=Ali |first7=M. |last8=Burgay |first8=M. |last9=Camilo |first9=F. |last10=Cognard |first10=I. |last11=Damour |first11=T. |display-authors=2 |date=2021-12-13 |title=Strong-Field Gravity Tests with the Double Pulsar |journal=Physical Review X |language=en-US |volume=11 |issue=4 |page=041050 |doi=10.1103/physrevx.11.041050 |arxiv=2112.06795 |bibcode=2021PhRvX..11d1050K |s2cid=245124502 |issn=2160-3308|doi-access=free }}</ref><ref>{{Cite journal|last=Shao|first=Lijing|date=2021-12-13|title=General Relativity Withstands Double Pulsar's Scrutiny|url=https://physics.aps.org/articles/v14/173|journal=Physics|language=en|volume=14|page=173 |doi=10.1103/Physics.14.173 |s2cid=247276989 |doi-access=free}}</ref><ref>{{Cite web |last1=Deller |first1=Adam |last2=Manchester |first2=Richard |date=December 13, 2021 |title=We counted 20 billion ticks of an extreme galactic clock to give Einstein's theory of gravity its toughest test yet |url=http://theconversation.com/we-counted-20-billion-ticks-of-an-extreme-galactic-clock-to-give-einsteins-theory-of-gravity-its-toughest-test-yet-173157 |access-date=2021-12-16 |website=The Conversation |language=en}}</ref>

===Unique origin===
In addition to the importance of this system to tests of general relativity, [[Tsvi Piran|Piran]] and [[Nir Shaviv|Shaviv]] have shown that the young pulsar in this system must have been born with no mass ejection, implying a new process of [[neutron star]] formation that does not involve a supernova.<ref>{{cite journal |first1=T. |last1=Piran |first2=N. |last2=Shaviv |s2cid=42212345 |title=Origin of the Binary Pulsar J0737−3039B |journal= Physical Review Letters|volume=95 |issue= 5|pages=051102 |year=2005 |doi=10.1103/PhysRevLett.94.051102 |pmid=15783626 |arxiv=astro-ph/0409651 |bibcode=2005PhRvL..94e1102P }}</ref> Whereas the standard supernova model predicts that the system will have a proper motion of more than hundred km/s, they predicted that this system would not show any significant proper motion. Their prediction was later confirmed by pulsar timing.<ref>{{cite journal |first1=M. |last1=Kramer |first2=I. H. |last2=Stairs |first3=R. N. |last3=Manchester |first4=M. A. |last4=McLaughlin |first5=A. G. |last5=Lyne |display-authors=1 |title=Strong-field tests of gravity with the double pulsar |journal=[[Annalen der Physik]] |volume=15 |issue=1–2 |pages=34–42 |year=2006 |doi=10.1002/andp.200510165 |bibcode=2006AnP...518...34K |s2cid=55380143 }}</ref>

===Eclipses===
Another discovery from the double pulsar is the observation of an eclipse from a [[Astronomical conjunction|conjunction]] of the superior and weaker pulsar. This happens when the [[toroid|doughnut]] shaped [[magnetosphere]] of one pulsar, which is filled with absorbing [[plasma (physics)|plasma]], blocks the companion pulsar's light. The blockage, lasting more than 30&nbsp;s, is not complete, due to the orientation of the plane of rotation of the binary system relative to Earth and the limited size of the weaker pulsar's [[magnetosphere]]; some of the stronger pulsar's light can still be detected during the eclipse.

== Other binary systems ==
In addition to a double pulsar system, a whole range of differing [[two-body problem|two-body systems]] are known where only one member of the system is a pulsar.  Known examples are variations on a [[binary star]] :
:A pulsar–[[white dwarf]] system; e.g, [[PSR B1620−26]].
:A pulsar–[[neutron star]] system, e.g, [[PSR B1913+16]].
:A pulsar and a [[main sequence star|normal star]]; e.g, PSR J0045−7319, a system that is composed of a pulsar and main-sequence [[B star]].

Theoretically, a pulsar-black hole system is possible and would be of enormous scientific interest but no such system has yet been identified.  A pulsar has recently been detected<ref>A magnetar / SGR / radio pulsar only 3” from Sgr A* "[http://bknispel.bplaced.de/2013/05/03/a-magnetar-sgr-radio-pulsar-only-3-from-sgr-a/] {{Webarchive|url=https://web.archive.org/web/20140202231438/http://bknispel.bplaced.de/2013/05/03/a-magnetar-sgr-radio-pulsar-only-3-from-sgr-a/ |date=February 2, 2014 }}".</ref> very near the super-massive black hole at the core of our galaxy, but its motion has not yet been officially confirmed as a capture orbit of Sgr A*. A pulsar–black hole system could be an even stronger test of Einstein's theory of general relativity, due to the immense [[gravity|gravitational forces]] exerted by both celestial objects. 

Also of great scientific interest is [[PSR J0337+1715]], a pulsar-white dwarf binary system that has a third white dwarf star in a more distant orbit circling around both of the other two.  This unique arrangement is being used to explore the [[strong equivalence principle]] of physics, a fundamental assumption upon which all of [[general relativity]] rests.

The [[Square Kilometre Array]], a [[radio telescope]] due to be completed in the late 2020s, will both further observe known and detect new binary pulsar systems in order to test [[general relativity]].<ref>{{Cite book |last=Kramer |first=Michael |title=Proceedings of from Planets to Dark Energy: The Modern Radio Universe — PoS(MRU) |chapter=Strong-field tests of gravity using pulsars & black holes |date=2008-10-14 |chapter-url=http://www.skatelescope.org/pages/science_genp_key_pulsars.htm |url-status=dead |page=020 |location=Trieste, Italy |publisher=Sissa Medialab |doi=10.22323/1.052.0020 |archive-url=https://web.archive.org/web/20101206093021/http://www.skatelescope.org/pages/science_genp_key_pulsars.htm |archive-date=December 6, 2010 |access-date=2010-07-06 |doi-access=free }}</ref>

== See also ==
* [[Radio astronomy]]

==References==
{{Reflist|

<ref name="Silva2021">{{cite journal
  |first1 = Hector O. |last1 = Silva
  |first2 = A. Miguel |last2 = Holgado
  |first3 = Alejandro |last3 = Cárdenas-Avendaño
  |first4 = Nicolás |last4 = Yunes
  |title      = Astrophysical and Theoretical Physics Implications from Multimessenger Neutron Star Observations
  |journal    = Physical Review Letters
  |date       = May 2021
  |volume     = 126
  |issue      = 18
  |page       = 181101
  |doi        = 10.1103/PhysRevLett.126.181101
  |pmid       = 34018776
  |arxiv      = 2004.01253
  |bibcode    = 2021PhRvL.126r1101S
  |s2cid      = 214795272
 }}</ref>

}}

==External links==
* {{cite web|url=http://www.jb.man.ac.uk/news/2004/doublepulsar/|title=First-Known Double Pulsar Opens up New Astrophysics|publisher=University of Manchester|date=8 January 2004}}
* {{cite web|url=http://www.atnf.csiro.au/research/highlights/2003/manchester/manchester.html|title=The first double pulsar|date=December 14, 2022 |publisher=Australia Telescope National Facility}}
* {{cite simbad|title=PSR J0737-3039}}
* {{cite web|url=http://vintage.portaldoastronomo.org/noticia.php?id=354|title=Pulsares trazem boas notícias aos caçadores de ondas gravitacionais|date=26 December 2003|website=Portal do Astrónomo|language=pt|trans-title=Pulsars bring good news to gravitational wave hunters}}
* {{cite journal|url=https://www.ufn.ru/en/news/2004/1/|title=A pulsar in a close pair|date=1 January 2004|journal=Physics-Uspekhi}}
* {{cite web|url=http://www.physics.mcgill.ca/~bretonr/doublepulsar/|title=Rene's Double Pulsar Page|work=Rene's Homepage|archive-url=https://web.archive.org/web/20140812182625/http://www.physics.mcgill.ca/~bretonr/doublepulsar/|archive-date=12 August 2014}}
* {{cite news|url=http://www.skyandtelescope.com/astronomy-news/new-binary-neutron-star-will-test-einstein/|title=New Binary Neutron Star Will Test Einstein|author=Naeye, Robert|date=12 December 2003|work=Sky and Telescope}}
* {{cite news|url=http://www.skyandtelescope.com/astronomy-news/einstein-passes-new-tests/|title=Einstein Passes New Tests|author=Naeye, Robert|date=3 March 2005|work=Sky and Telescope}}
* {{cite news|url=https://www.mpg.de/18014666/einstein-relativity-theory-tests|title=Einstein proven right yet again|author= Norbert Junkes|date=13 December 2021|work=Max-Planck-Gesellschaft}}

{{Puppis}}

{{DEFAULTSORT:PSR J0737-3039}}
[[Category:Puppis]]
[[Category:Pulsars]]
[[Category:Double neutron star systems]]