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| {{Starbox begin
| | When a canopy garage door parts, their service packages and charges you can store in your home. Utah is bustling with several paneling garage door services traverse city options. Are garage door services traverse city you a few days after installation. Children should not be as difficult as it is possible to buy. In case you are looking for an online tour of their [http://www.Alexa.com/search?q=custom+wood&r=topsites_index&p=bigtop custom wood] doors and frames are mainly used for residential purposes.<br><br> |
| | name=PSR J1614–2230}}
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| {{Starbox observe
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| | epoch=J2000
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| | ra={{RA|16|14|36.5051}}<ref name="Demorest2010" />
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| | dec={{DEC|-22|30|31.081}}<ref name="Demorest2010" />
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| | constell=[[Scorpius]]}}
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| {{Starbox character
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| | class=Pulsar}}
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| {{Starbox astrometry
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| | radial_v=
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| | prop_mo_ra=
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| | prop_mo_dec=
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| | parallax=
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| | p_error=
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| | dist_pc= 1,200<ref name="Demorest2010" />
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| }}
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| {{Starbox detail
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| | mass=1.97<ref name="Demorest2010" />
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| | radius=13±2 km,<ref name="Demorest2010" /> 1.87(29){{Esp|-5}} <!--solar radii-->
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| | luminosity=
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| | temperature=
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| | metal=
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| | rotation= 3.1508076534271 [[millisecond|ms]]<ref name="Demorest2010" />
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| | age=5.2{{Esp|9}}}}
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| {{Starbox catalog
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| | names= PSR J1614–22}}
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| {{Starbox end}}
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| '''PSR J1614–2230''' is a [[neutron star]] in a binary system with a [[white dwarf]]. It was discovered in 2006 with the [[Parkes Observatory|Parkes telescope]] in a survey of unidentified [[gamma ray]] sources in the [[Energetic Gamma Ray Experiment Telescope]] catalog.<ref name="Crawford2006" /> PSR J1614–2230 is a [[millisecond pulsar]], a type of neutron star, that spins on its axis roughly 317 times per second, corresponding to a period of 3.15 milliseconds. Like all pulsars, it emits radiation in a beam, similar to a [[lighthouse]].<ref name="bbc">{{cite news | url = http://www.bbc.co.uk/news/science-environment-11639458 | title = Neutron star packs two Suns' mass in London-sized space | author = Jonathan Amos | journal = BBC | date = October 28, 2010 | accessdate = 2010-10-28}}</ref> Emission from PSR J1614–2230 is observed as pulses at the spin period of PSR J1614–2230. The pulsed nature of its emission allows for the arrival of individual pulses to be timed. By measuring the arrival time of pulses, [[astronomer]]s observed the delay of pulse arrivals from PSR J1614–2230 when it was passing behind its companion from the vantage point of [[Earth]]. By measuring this delay, known as the [[Shapiro delay]], astronomers determined the mass of PSR J1614–2230 and its companion. The team performing the observations found that the mass of PSR J1614–2230 is <math>1.97 \pm 0.04 M_\odot</math>. This mass made PSR J1614–2230 the most massive known [[neutron star]] at the time of discovery, and rules out many neutron star [[equation of state|equations of state]] that include exotic [[matter]] such as [[hyperon]]s and [[kaon]] condensates.<ref name="Demorest2010" />
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| In 2013, a slightly higher neutron star mass measurement was announced for [[PSR J0348+0432]], <math>2.01 \pm 0.04 M_\odot</math>.<ref name="Antoniadis2013" />
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| This confirmed the existence of such massive neutron stars using a different measuring technique.
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| ==Background==
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| {{main|Pulsar}}
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| [[Image:Pulsar schematic.svg|thumb|right|Schematic view of a pulsar. The sphere in the middle represents the neutron star, the curves indicate the magnetic field lines and the protruding cones represent the emission beams.]]
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| [[Pulsar]]s were discovered in 1967 by [[Jocelyn Bell]] and her adviser [[Antony Hewish]] using the [[Interplanetary Scintillation Array]].<ref name="Hewish1968" /> [[Franco Pacini]] and [[Thomas Gold]] quickly put forth the idea that pulsars are highly [[magnetism|magnetized]] rotating [[neutron star]]s, which form as a result of a [[Type II supernova|supernova]] at the end of the life of [[star]]s more massive than about 10 times the mass of the [[Sun]].<ref name="Pacini1968" /><ref name="Gold1968" /> The [[electromagnetic radiation|radiation]] emitted by pulsars is caused by interaction of the [[plasma (physics)|plasma]] surrounding the neutron star with its rapidly rotating magnetic field. This interaction leads to emission "in the pattern of a rotating beacon," as emission escapes along the magnetic poles of the neutron star.<ref name="Gold1968" /> The "rotating beacon" property of pulsars arises from the misalignment of their magnetic poles with their rotational poles. Historically, pulsars have been discovered at [[radio wave]]lengths where emission is strong, but [[space telescope]]s that operate in the [[gamma ray]] wavelengths have also discovered pulsars.
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| ==Observations==
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| The [[Energetic Gamma-Ray Experiment Telescope]] (EGRET) identified a half dozen known pulsars at gamma ray wavelengths. Many of the sources it detected had no known counterparts at other wavelengths. In order to see whether any of these sources were pulsars, Fronefield Crawford ''et al.'' used the [[Parkes Observatory|Parkes telescope]] to conduct a survey of the EGRET sources located in the plane of the [[Milky Way]] that lacked a known counterpart. In the search, they discovered PSR J1614–2230, and concluded that it might be a counterpart to a gamma ray source near the same location.<ref name="Crawford2006" /> The radio observations revealed that PSR J1614–2230 had a companion, likely a [[white dwarf]]. The observed orbital parameters of the system indicated a minimum companion mass of <math>0.4 M_\odot</math>, and an orbital period of 8.7 days.<ref name="Hessels2005" />
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| Paul Demorest ''et al.'' used the [[Green Bank Telescope]] at the [[National Radio Astronomy Observatory]] to observe the system through a complete 8.7 day orbit, recording the pulse arrival times from PSR J1614–2230 over this period. After accounting for factors that would alter pulse arrival times from exactly matching its period of 3.1508076534271 milliseconds, including the [[orbital parameter]]s of the binary system, the spin of the pulsar, and the motion of the system, Demorest ''et al.'' determined the delay in the arrival of pulses that resulted from the pulse having to travel past the companion to PSR J1614–2230 on its way to [[Earth]]. This delay is a consequence of [[general relativity]] known as the [[Shapiro delay]], and the magnitude of the delay is dependent upon the mass of the white dwarf companion. The best fit companion mass was <math>0.500 \pm 0.006 M_\odot</math>. Knowing the companion mass and orbital elements then provided enough information to determine the mass of PSR J1614–2230 to be <math>1.97 \pm 0.04 M_\odot</math>.<ref name="Demorest2010" />
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| ==Significance==
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| The conditions in neutron stars are very different from those encountered on Earth, as a result of the high [[density]] and [[gravity]] of neutron stars; their masses are of order the mass of a [[star]], but they have sizes around {{convert|10|km}} in diameter, which is comparable to the size of the center of large cities such as [[London]].<ref name="bbc" /> Neutron stars also have the property that as they become more massive, their diameter decreases. The mass of PSR J1614–2230 is the highest of any known [[neutron star]]. The existence of a neutron star with such a high mass constrains the composition and structure of neutron stars, both of which are poorly understood. The reason for this is that the maximum mass of a neutron star is dependent upon its composition. A neutron star composed of matter such as [[hyperon]]s or [[kaon]] [[condensate]]s{{disambiguation needed|date=March 2013}} would collapse to form a [[black hole]] before it could reach the observed mass of PSR J1614–2230, meaning neutron star models that include such matter are strongly constrained by this result.<ref name="Demorest2010" /><ref name="nature">{{cite news | url = http://www.nature.com/news/2010/101027/full/news.2010.565.html | title = Massive neutron star is exactly that | author = Zeeya Merali | date = October 27, 2010 | journal = Nature | accessdate = 2010-10-29}}</ref>
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| ==Notes==
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| {{reflist|refs=
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| <ref name="Crawford2006">[[#Crawford2006|Crawford et al. (2006)]]</ref>
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| <ref name="Demorest2010">[[#Demorest2010|Demorest et al. (2010)]]</ref>
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| <ref name="Antoniadis2013">[[#Antoniadis2013|Antoniadis et al. (2013)]]</ref>
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| <ref name="Gold1968">[[#Gold1968|Gold (1968)]]</ref>
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| <ref name="Hessels2005">[[#Hessels2005|Hessels et al. (2005)]]</ref>
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| <ref name="Hewish1968">[[#Hewish1968|Hewish et al. (1968)]]</ref>
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| <ref name="Pacini1968">[[#Pacini1968|Pacini (1968)]]</ref>
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| }}
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| ==References==
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| *<cite id = Crawford2006>{{cite doi | 10.1086/508403}}</cite>
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| *<cite id = Demorest2010>{{cite doi | 10.1038/nature09466}}</cite>
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| *<cite id = Antoniadis2013>{{cite doi | 10.1126/science.1233232}}</cite>
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| *<cite id = Gold1968>{{cite doi | 10.1038/218731a0}}</cite>
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| *<cite id = Hessels2005>{{cite conference | title = Three New Binary Pulsars Discovered With Parkes | author = Hessels, J.; Ransom, S.; Roberts, M.; [[Victoria Kaspi|Kaspi, V.]]; Livingstone, M.; Tam, C.; Crawford, F. | booktitle = Binary Radio Pulsars | publisher = Astronomical Society of the Pacific | volume = 328 | date = January 11–17, 2004 | location = Aspen, Colorado, USA | editor = F. A. Rasio and I. H. Stairs | year = 2005 | url = http://adsabs.harvard.edu/abs/2005ASPC..328..395H}}</cite>
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| *<cite id = Hewish1968>{{cite doi | 10.1038/217709a0}}</cite>
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| *<cite id = Pacini1968>{{cite doi | 10.1038/219145a0}}</cite>
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| {{Stars of Scorpius}}
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| {{DEFAULTSORT:PSR J1614-2230}}
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| [[Category:Scorpius (constellation)]]
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| [[Category:Pulsars]]
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| [[Category:Millisecond pulsars]]
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| [[Category:Neutron stars]]
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