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A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses (M☉), possibly more if the star was especially metal-rich. Except for black holes, neutron stars are the smallest and densest known class of stellar objects. Neutron stars have a radius on the order of 10 kilometers (6 mi) and a mass of about 1.4 M☉. They result 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.
A magnetar is a type of neutron star with an extremely powerful magnetic field (~109 to 1011 T, ~1013 to 1015 G). The magnetic-field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays.
A stellar black hole is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. The process is observed as a hypernova explosion or as a gamma ray burst. These black holes are also referred to as collapsars.
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.
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.
The Crab Pulsar is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054. Discovered in 1968, the pulsar was the first to be connected with a supernova remnant.
Geminga is a gamma ray and x-ray pulsar source thought to be a neutron star approximately 250 parsecs from the Sun in the constellation Gemini.
Cassiopeia A (Cas A) is a supernova remnant (SNR) in the constellation Cassiopeia and the brightest extrasolar radio source in the sky at frequencies above 1 GHz. The supernova occurred approximately 11,000 light-years (3.4 kpc) away within the Milky Way; given the width of the Orion Arm, it lies in the next-nearest arm outwards, the Perseus Arm, about 30 degrees from the Galactic anticenter. The expanding cloud of material left over from the supernova now appears approximately 10 light-years (3 pc) across from Earth's perspective. It has been seen in wavelengths of visible light with amateur telescopes down to 234 mm (9.25 in) with filters.
W49B is a nebula in Westerhout 49 (W49). The nebula is a supernova remnant, probably from a type Ib or Ic supernova that occurred around 1,000 years ago. It may have produced a gamma-ray burst and is thought to have left a black hole remnant.
An ultraluminous X-ray source (ULX) is an astronomical source of X-rays that is less luminous than an active galactic nucleus but is more consistently luminous than any known stellar process (over 1039 erg/s, or 1032 watts), assuming that it radiates isotropically (the same in all directions). Typically there is about one ULX per galaxy in galaxies which host them, but some galaxies contain many. The Milky Way has not been shown to contain a ULX, although SS 433 may be a possible source. The main interest in ULXs stems from their luminosity exceeding the Eddington luminosity of neutron stars and even stellar black holes. It is not known what powers ULXs; models include beamed emission of stellar mass objects, accreting intermediate-mass black holes, and super-Eddington emission.
IC 443 is a galactic supernova remnant (SNR) in the constellation Gemini. On the plane of the sky, it is located near the star Eta Geminorum. Its distance is roughly 5,000 light years from Earth.
A radio-quiet neutron star is a neutron star that does not seem to emit radio emissions, but is still visible to Earth through electromagnetic radiation at other parts of the spectrum, particularly X-rays and gamma rays.
RX J0852.0−4622 is a supernova remnant. The remnant is located in the southern sky in the constellation Vela ("sail"), and sits inside the much larger and older Vela Supernova Remnant. For this reason, RX J0852.0−4622 is often referred to as Vela Junior. There have been a minority of suggestions that the remnant may be a spurious identification of a complicated substructure within the larger and better studied Vela SNR, but most studies accept that G266.2−1.2 is a SNR in its own right. Indeed, its detection in the high energy Teraelectronvolt range by the High Energy Stereoscopic System in 2005 is strong confirmation of such.
In astronomy, Calvera is an X-ray source in the constellation Ursa Minor, identified in 2007 as an isolated neutron star. It is one of the hottest and closest of its kind to Earth.
RX J0822−4300, often referred to as a "Cosmic Cannonball", is a radio-quiet neutron star currently moving away from the center of the Puppis A supernova remnant at over 3 million miles per hour, making it one of the fastest moving stars ever found. Astronomers used NASA's Chandra X-ray Observatory to observe the star over a period of five years to determine its speed. At this velocity the star will be ejected from the galaxy millions of years from now.
PSR J0855-4644 is a pulsar in the constellation Vela, and was at one time thought possibly associated with supernova remnant RX J0852.0-4622. However, this association is considered unlikely since a central compact object with better matching kinematics to the shell has been observed.
Circinus X-1 is an X-ray binary star system that includes a neutron star. Observation of Circinus X-1 in July 2007 revealed the presence of X-ray jets normally found in black hole systems; it is the first of the sort to be discovered that displays this similarity to black holes. Circinus X-1 may be among the youngest X-ray binaries observed.
IGR J11014−6103, also called the Lighthouse Nebula, is a pulsar wind nebula trailing the neutron star which has the longest relativistic jet observed in the Milky Way.
Imaging X-ray Polarimetry Explorer, commonly known as IXPE or SMEX-14, is a space observatory with three identical telescopes designed to measure the polarization of cosmic X-rays of black holes, neutron stars, and pulsars. The observatory, which was launched on 9 December 2021, is an international collaboration between NASA and the Italian Space Agency (ASI). It is part of NASA's Explorers program, which designs low-cost spacecraft to study heliophysics and astrophysics.
SGR 1935+2154 is a soft gamma repeater (SGR) that is an ancient stellar remnant, in the constellation Vulpecula, originally discovered in 2014 by the Neil Gehrels Swift Observatory. Currently, the SGR-phenomena and the related anomalous X-ray pulsars (AXP) are explained as arising from magnetars. On 28 April 2020, this remnant about 30,000 light-years away in our Milky Way galaxy was observed to be associated with a very powerful radio pulse known as a fast radio burst or FRB, and a related x-ray flare. The detection is notable as the first FRB detected inside the Milky Way, and the first to be linked to a known source. Later in 2020, SGR 1935+2154 was found to be associated with repeating fast radio bursts.
References
- ↑ Mayer, Martin G. F.; Becker, Werner (2021-07-01). "A kinematic study of central compact objects and their host supernova remnants". Astronomy & Astrophysics. 651: A40. doi: 10.1051/0004-6361/202141119 . ISSN 0004-6361.
- ↑ Tuohy, I.; Garmire, G. (1980-08-01). "Discovery of a compact X-ray source at the center of the SNR RCW 103". The Astrophysical Journal. 239: L107–L110. Bibcode:1980ApJ...239L.107T. doi:10.1086/183303. ISSN 0004-637X.
- 1 2 De Luca, A (2017). "Central compact objects in supernova remnants". Journal of Physics: Conference Series. 932: 012006. doi:10.1088/1742-6596/932/1/012006.
- ↑ www.iasf-milano.inaf.it https://www.iasf-milano.inaf.it/~deluca/cco/main.htm . Retrieved 2023-12-12.
{{cite web}}: Missing or empty|title=(help) - ↑ Gotthelf, E. V.; Halpern, J. P. (2009-04-01). "Discovery of a 112 ms X-Ray Pulsar in Puppis A: Further Evidence of Neutron Stars Weakly Magnetized at Birth". The Astrophysical Journal. 695 (1): L35–L39. arXiv: 0902.3007 . Bibcode:2009ApJ...695L..35G. doi: 10.1088/0004-637X/695/1/L35 . ISSN 0004-637X.
- ↑ Zavlin, V. E.; Pavlov, G. G.; Sanwal, D.; Trümper, J. (2000-09-01). "Discovery of 424 Millisecond Pulsations from the Radio-quiet Neutron Star in the Supernova Remnant PKS 1209-51/52". The Astrophysical Journal. 540 (1): L25–L28. arXiv: astro-ph/0005548 . Bibcode:2000ApJ...540L..25Z. doi: 10.1086/312866 . ISSN 0004-637X.
- ↑ Gotthelf, E. V.; Halpern, J. P.; Seward, F. D. (2005-07-01). "Discovery of a 105 ms X-Ray Pulsar in Kesteven 79: On the Nature of Compact Central Objects in Supernova Remnants". The Astrophysical Journal. 627 (1): 390–396. arXiv: astro-ph/0503424 . Bibcode:2005ApJ...627..390G. doi:10.1086/430300. ISSN 0004-637X. S2CID 12492328.
