Below is a list of high-mass neutron stars.
| Name | Mass (M☉) | Distance (ly) | Companion class | Mass determination method | Notes | Refs. |
|---|---|---|---|---|---|---|
| PSR J1748-2021B | 2.548+0.047 −0.078 | 27,700 | D | Rate of advance of periastron. | In globular cluster NGC 6440. | [1] [2] [3] [4] |
| 4U 1700-37 | 2.44±0.27 | 6,910 ± 1,120 | O6.5Iaf+ | Monte Carlo simulations of thermal comptonization process. | HMXB system. | [5] [6] |
| PSR J0952–0607 | 2.35±0.17 | 3,200–5,700 | Substellar object | Radio-measured Shapiro delay | Black widow pulsar. Fastest spinning galactic pulsar. | [7] |
| PSR J1311–3430 | 2.15–2.7 | 6,500–12,700 | Substellar object | Spectroscopic and photometric observation. | Black widow pulsar. | [8] [9] |
| PSR J1600−3053 | 2.3+0.7 −0.6 | 6,500 ± 1,000 | D | Fourier analysis of Shapiro delay's orthometric ratio. | [10] [11] | |
| PSR J2215+5135 | 2.27+0.17 −0.15 | 10,000 | G5V | Innovative measurement of companion's radial velocity. | Redback pulsar. | [12] |
| XMMU J013236.7+303228 | 2.2+0.8 −0.6 | 2,730,000 | B1.5IV | Detailed spectroscopic modelling. | In M33, HMXB system. | [13] |
| PSR J0751+1807 | 2.10±0.2 | 6,500 ± 1,300 | D | Precision pulse timing measurements of relativistic orbital decay. | [14] | |
| PSR J0740+6620 | 2.08±0.07 | 4,600 | D | Range and shape parameter of Shapiro delay. | Most massive neutron star with a well-constrained mass. | [15] [16] [17] |
| PSR J0348+0432 | 2.01±0.04 | 2,100 | D | Spectroscopic observation and orbital decay due to radiation of gravitational waves. | [10] [18] | |
| PSR B1516+02B | 1.94+0.17 −0.19 | 24,500 | D | Rate of advance of periastron. | In globular cluster M5. | [10] [19] |
| PSR J1614−2230 | 1.908±0.016 | 3,900 | D | Range and shape parameter of Shapiro delay. | In Milky Way's galactic disk. | [10] [11] [20] |
| Vela X-1 | 1.88±0.13 | 6,200 ± 650 | B0.5Ib | Rate of advance of periastron. | Prototypical detached HMXB system. | [21] |
| PSR B1957+20 | 1.81±0.17 | 6,500 | Substellar object | Rate of advance of periastron. | Prototype star of black widow pulsars. | [22] [23] [24] |
A neutron star is the collapsed core of a massive supergiant star. It results from the supernova explosion of a massive star—combined with gravitational collapse—that compresses the core past white dwarf star density to that of atomic nuclei. Except for black holes, neutron stars are the smallest and densest known class of stellar objects. They have a radius on the order of 10 kilometers (6 mi) and a mass of about 1.4 M☉. Stars that collapse into neutron stars have a total mass of between 10 and 25 solar masses (M☉), or possibly more for those that are especially rich in elements heavier than hydrogen and helium.
Einstein@Home is a volunteer computing project that searches for signals from spinning neutron stars in data from gravitational-wave detectors, from large radio telescopes, and from a gamma-ray telescope. Neutron stars are detected by their pulsed radio and gamma-ray emission as radio and/or gamma-ray pulsars. They also might be observable as continuous gravitational wave sources if they are rapidly spinning and non-axisymmetrically deformed. The project was officially launched on 19 February 2005 as part of the American Physical Society's contribution to the World Year of Physics 2005 event.
3C 58 or 3C58 is a pulsar and supernova remnant within the Milky Way. The object is listed as No. 58 in the Third Cambridge Catalogue of Radio Sources.
A pulsar is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth, and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.
A millisecond pulsar (MSP) is a pulsar with a rotational period less than about 10 milliseconds. Millisecond pulsars have been detected in radio, X-ray, and gamma ray portions of the electromagnetic spectrum. The leading hypothesis for the origin of millisecond pulsars is that they are old, rapidly rotating neutron stars that have been spun up or "recycled" through accretion of matter from a companion star in a close binary system. For this reason, millisecond pulsars are sometimes called recycled pulsars.
The Hulse–Taylor pulsar is a binary star system composed of a neutron star and a pulsar which orbit around their common center of mass. It is the first binary pulsar ever discovered.
A binary pulsar is a pulsar with a binary companion, often a white dwarf or neutron star. Binary pulsars are one of the few objects which allow physicists to test general relativity because of the strong gravitational fields in their vicinities. Although the binary companion to the pulsar is usually difficult or impossible to observe directly, its presence can be deduced from the timing of the pulses from the pulsar itself, which can be measured with extraordinary accuracy by radio telescopes.
The Tolman–Oppenheimer–Volkoff limit is an upper bound to the mass of cold, non-rotating neutron stars, analogous to the Chandrasekhar limit for white dwarf stars. Stars more massive than the TOV limit collapse into a black hole. The original calculation in 1939, which neglected complications such as nuclear forces between neutrons, placed this limit at approximately 0.7 solar masses (M☉). Later, more refined analyses have resulted in larger values.
PSR J1748−2446ad is the fastest-spinning pulsar known, at 716 Hz, or 42,960 revolutions per minute. This pulsar was discovered by Jason W. T. Hessels of McGill University on November 10, 2004, and confirmed on January 8, 2005.
PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the coordinates are for the 1950.0 epoch. PSR B1937+21 was discovered in 1982 by Don Backer, Shri Kulkarni, Carl Heiles, Michael Davis, and Miller Goss.
The Black Widow Pulsar is an eclipsing binary millisecond pulsar in the Milky Way. Discovered in 1988, it is located roughly 6,500 light-years away from Earth. It orbits with a brown dwarf or Super-Jupiter companion with a period of 9.2 hours with an eclipse duration of approximately 20 minutes. When it was discovered, it was the first such pulsar known. The prevailing theoretical explanation for the system implied that the companion is being destroyed by the strong powerful outflows, or winds, of high-energy particles caused by the neutron star; thus, the sobriquet black widow was applied to the object. Subsequent to this, other objects with similar features have been discovered, and the name has been applied to the class of millisecond pulsars with an ablating companion, as of February 2023 around 41 black widows are known to exist.
PSR J1614–2230 is a pulsar in a binary system with a white dwarf in the constellation Scorpius. It was discovered in 2006 with the Parkes telescope in a survey of unidentified gamma ray sources in the Energetic Gamma Ray Experiment Telescope catalog. 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. 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, astronomers 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 1.97 ± 0.04 M☉. This mass made PSR J1614–2230 the most massive known neutron star at the time of discovery, and rules out many neutron star equations of state that include exotic matter such as hyperons and kaon condensates.
PSR J1311–3430 is a pulsar with a spin period of 2.5 milliseconds. It is the first millisecond pulsar found via gamma-ray pulsations. The source was originally identified by the Energetic Gamma Ray Experiment Telescope as a bright gamma ray source, but was not recognized as a pulsar until observations with the Fermi Gamma-ray Space Telescope discovered pulsed gamma ray emission. The pulsar has a helium-dominated companion much less massive than itself, and the two are in an orbit with a period of 93.8 minutes. The system is explained by a model where mass from the low mass companion was transferred on to the pulsar, increasing the mass of the pulsar and decreasing its period. These systems are known as Black Widow Pulsars, named after the original such system discovered, PSR B1957+20, and may eventually lead to the companion being completely vaporized. Among systems like these, the orbital period of PSR J1311–3430 is the shortest ever found. Spectroscopic observations of the companion suggest that the mass of the pulsar is 2.7 . Though there is considerable uncertainty in this estimate, the minimum mass for the pulsar that the authors find adequately fits the data is 2.15 , which is still more massive than PSR J1614−2230, the previous record holder for most massive known pulsar.
PSR J0348+0432 is a pulsar–white dwarf binary system in the constellation Taurus. It was discovered in 2007 with the National Radio Astronomy Observatory's Robert C. Byrd Green Bank Telescope in a drift-scan survey.
Daryl Haggard is an American-Canadian astronomer and associate professor of physics in the Department of Physics at McGill University and the McGill Space Institute.
PSR J0740+6620 is a neutron star in a binary system with a white dwarf, located 4,600 light years away in the Milky Way galaxy. It was discovered in 2019, by astronomers using the Green Bank Telescope in West Virginia, U.S., and confirmed as a rapidly rotating millisecond pulsar.
PSR J0901–4046 is an ultra-long period pulsar. Its period, 75.9 seconds, is the longest for any known neutron star pulsar. Its period is more than three times longer than that of PSR J0250+5854, the previous long period record-holder. The pulses are narrow; radio emission is seen from PSR J0901–4046 for only 0.5% of its rotation period.
PSR J0952–0607 is a massive millisecond pulsar in a binary system, located between 3,200–5,700 light-years (970–1,740 pc) from Earth in the constellation Sextans. It holds the record for being the most massive neutron star known as of 2022, with a mass 2.35±0.17 times that of the Sun—potentially close to the Tolman–Oppenheimer–Volkoff mass upper limit for neutron stars. The pulsar rotates at a frequency of 707 Hz, making it the second-fastest-spinning pulsar known, and the fastest-spinning pulsar known within the Milky Way.
Pulsar planets are planets that are orbiting pulsars. The first such planets to be discovered were around a millisecond pulsar in 1992 and were the first extrasolar planets to be confirmed as discovered. Pulsars are extremely precise clocks and even small planets can create detectable variations in pulsar traits; the smallest known exoplanet is a pulsar planet.
PSR J1748-2021B is the most massive known pulsar, initially calculated with 2.74+0.21
−0.21 M☉. It was first discovered by Freire using the Green Bank Telescope S band receiver and Pulsar Spigot Spectrometer in Terzan 5 of globular cluster M-5.
| Types | |
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| Single pulsars |
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| Binary pulsars | |
| Properties | |
| Related | |
| Discovery | |
| Satellite investigation | |
| Other | |
