PSR J0952–0607: Difference between revisions

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m Added the Radius of the pulsar PSR J0952–0607 A and my source https://arxiv.org/abs/2306.05097. In their paper, the radius is Rmax.
 
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Latest revision as of 19:52, 26 December 2024

Template:Short description Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox detail Template:Starbox orbit Template:Starbox catalog Template:Starbox reference Template:Starbox end

PSR J0952–0607 is a massive millisecond pulsar in a binary system, located between Template:Convert from Earth in the constellation Sextans.[1] It holds the record for being the most massive neutron star known Template:Asof, with a mass Template:Val times that of the Sun—potentially close to the Tolman–Oppenheimer–Volkoff mass upper limit for neutron stars.[2][3] The pulsar rotates at a frequency of 707 Hz (1.41 ms period), making it the second-fastest-spinning pulsar known, and the fastest-spinning pulsar known within the Milky Way.[4][1]

PSR J0952–0607 was discovered by the Low-Frequency Array (LOFAR) radio telescope during a search for pulsars in 2016.[1] It is classified as a black widow pulsar, a type of pulsar harboring a closely-orbiting substellar-mass companion that is being ablated by the pulsar's intense high-energy solar winds and gamma-ray emissions.[2][5] The pulsar's high-energy emissions have been detected in gamma-ray and X-ray wavelengths.[6][7][8]

Discovery

PSR J0952–0607 was first identified as an unassociated gamma-ray source detected during the first seven years of the Fermi Gamma-ray Space Telescope's all-sky survey since 2008.[4]Template:Rp Because of its optimal location away from the crowded Galactic Center and its pulsar-like[9]Template:Rp gamma-ray emission peak at 1.4 GeV, it was deemed a prime millisecond pulsar candidate for follow-up.[4]Template:Rp The pulsar was reobserved and confirmed by the Low-Frequency Array (LOFAR) radio telescope in the Netherlands on 25 December 2016, which revealed a 707-Hz radio pulsation frequency alongside radial acceleration by an unseen binary companion.[4]Template:Rp Further LOFAR observations took place from January to February 2017, alongside radio observations by the Green Bank Telescope in Green Bank, West Virginia in March 2017.[4]Template:Rp Optical observations by the 2.54-meter Isaac Newton Telescope on La Palma detected and confirmed the pulsar's companion at a faint apparent magnitude of 23 in January 2017.[4]Template:Rp The discovery was published in The Astrophysical Journal Letters and was announced in a NASA press release in September 2017.[4][1]

Distance and location

The distance of PSR J0952–0607 from Earth is highly uncertain.[10][7][2]

Binary system

The PSR J0952–0607 binary system is composed of a massive pulsar and a substellar-mass (<Template:Val)[5]Template:Rp companion in close orbit around it.[2] Because of this configuration, this system falls under the category of black widow pulsars that "consume" their companion, by analogy with the mating behavior of the eponymous black widow spider.[3] The companion is continuously losing mass through ablation by intense high-energy solar winds and gamma-ray emissions from the pulsar, which then accretes some of the companion's lost material onto itself.[5]Template:Rp[2]Template:Rp

Companion

Artist's impression of a black widow pulsar system, where a stellar-mass companion is being ablated by the intense radiation of its host pulsar

The companion orbits the pulsar at a distance of Template:ConvertTemplate:Efn with an orbital period of 6.42 hours.[2] Because it orbits so closely, the companion is presumably tidally locked, with one hemisphere always facing the pulsar.[7]Template:Rp The companion does not appear to eclipse the pulsar,[4]Template:Rp[7]Template:Rp indicating that its orbit is oriented nearly face-on with an inclination of 60° with respect to the plane perpendicular to Earth's line of sight.[2]Template:Rp The companion's orbital motion also does not appear to modulate the pulsar's pulsations, signifying a circular orbit with negligible orbital eccentricity.[7]Template:Rp

The companion was likely a former star that had been reduced to the size of a large gas giant planet or brown dwarf,[3][7]Template:Rp with a present-day mass of Template:Val or Template:Val according to radial velocity measurements.[2]Template:Rp Due to intense irradiation and heating by the host pulsar, the companion's radius is bloated up to 80% of its Roche lobe[7]Template:Rp[2]Template:Rp and brightly glows with a thermal luminosity of about Template:Val,Template:Efn thereby accounting for much of the system's optical brightness.[2]Template:Rp[10]Template:Rp As a result of bloating, the companion attains a low density likely around Template:Val (with significant uncertainty due to the system's unknown distance from Earth),[10]Template:Rp making it susceptible to tidal deformation by the pulsar.[7]Template:Rp

The companion's pulsar-facing irradiated hemisphere is continuously heated up to a temperature of Template:Val, whereas the companion's unirradiated hemisphere experiences a uniform[10]Template:Rp temperature of Template:Val.[2]Template:Rp This hemispherical temperature difference corresponds to a difference in hemisphere luminosities, which in turn causes significant variability in apparent brightness as the companion rotates around the pulsar.[4]Template:Rp[7]Template:Rp This brightness variability is demonstrated in PSR J0952–0607's optical light curve, which exhibits an amplitude greater than one magnitude.[10]Template:Rp

Mass

PSR J0952–0607 has a mass of Template:Val, making it the most massive neutron star known Template:Asof.[2] The pulsar likely acquired most of its mass by accreting up to Template:Val of lost material from its companion.[2]Template:Rp

Rotation and age

PSR J0952–0607 rotates at a frequency of 707 Hz (1.41 ms period), making it the second-fastest-spinning pulsar known, and the fastest-spinning pulsar that is located in the Milky Way.[4][1] Assuming a standard neutron star radius of Template:Cvt,[7]Template:Rp the equator of PSR J0952–0607 rotates at a tangential velocity over Template:Cvt—about 14% the speed of light.[11] Based on 7 years of precise pulsation timing data from gamma-ray and radio observations, the pulsar's rotation period is estimated to be slowing down at a spin-down rate less than Template:Val seconds per second, corresponding to a characteristic age of 4.9 billion years.[7]Template:Rp

Magnetic field

Measurements of PSR J0952–0607's spin-down rate show that the pulsar has a remarkably weak surface magnetic field strength of Template:Convert, placing it among the 10 weakest pulsar magnetic fields known Template:Asof.[2]Template:Rp For context, ordinary pulsar magnetic fields usually lie on the order of teragauss (Template:Cvt), over 10,000 times greater than that of PSR J0952–0607.[12][2]Template:Rp Other millisecond pulsars exhibit similarly weak magnetic fields, hinting at a common albeit unknown mechanism in these types of systems;[7]Template:Rp possible explanations range from accreted matter burying the pulsar's surface magnetic field to heat-driven evolution of the pulsar's solid crust.[12]Template:Rp[2]Template:Rp

Gamma-ray emissions

PSR J0952–0607 appears very faint in gamma-rays and was not detected in July 2011.[8][7]Template:Rp

See also

Notes

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References

Template:Reflist

Template:2022 in space Template:Sextans

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Cite error: Invalid <ref> tag; no text was provided for refs named NASA2017
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 Cite error: Invalid <ref> tag; no text was provided for refs named Romani2022
  3. ↑ 3.0 3.1 3.2 Cite error: Invalid <ref> tag; no text was provided for refs named Berkeley
  4. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 Cite error: Invalid <ref> tag; no text was provided for refs named Bassa2017
  5. ↑ 5.0 5.1 5.2 Cite error: Invalid <ref> tag; no text was provided for refs named Roberts2013
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Ho2019
  7. ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 7.12 Cite error: Invalid <ref> tag; no text was provided for refs named Nieder2019
  8. ↑ 8.0 8.1 Cite error: Invalid <ref> tag; no text was provided for refs named Kohler2019
  9. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Abdollahi2020
  10. ↑ 10.0 10.1 10.2 10.3 10.4 Cite error: Invalid <ref> tag; no text was provided for refs named Draghis2019
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named ScienceAlert2019
  12. ↑ 12.0 12.1 Cite error: Invalid <ref> tag; no text was provided for refs named Mukherjee2017
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