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X-ray pulsar-based navigation and timing (XNAV) or simply pulsar navigation is a navigation technique whereby the periodic X-ray signals emitted from pulsars are used to determine the location of a vehicle, such as a spacecraft in deep space. A vehicle using XNAV would compare received X-ray signals with a database of known pulsar frequencies ...
An X-ray pulsar is a type of binary star system consisting of a typical star (stellar companion) in orbit around a magnetized neutron star.The magnetic field strength at the surface of the neutron star is typically about 10 8 Tesla, over a trillion times stronger than the strength of the magnetic field measured at the surface of the Earth (60 μT).
An intermediate-mass binary pulsar (IMBP) is a pulsar-white dwarf binary system with a relatively long spin period of around 10–200 ms consisting of a white dwarf with a relatively high mass of approximately . [7] The spin periods, magnetic field strengths, and orbital eccentricities of IMBPs are significantly larger than those of low mass binary pulsars (LMBPs). [7]
PSR B1919+21 is a pulsar with a period of 1.3373 seconds [4] and a pulse width of 0.04 seconds. Discovered by Jocelyn Bell Burnell on 28 November 1967, it is the first discovered radio pulsar. [5]
These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers. The discovery of the cosmic microwave background radiation , regarded as evidence for the Big Bang theory , was made through radio astronomy.
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.
The pulsar provides a strong periodic signal that is used to check the timing of the X-ray detectors. In X-ray astronomy, "crab" and "millicrab" are sometimes used as units of flux density. A millicrab corresponds to a flux density of about 2.4 × 10 −11 erg s −1 cm −2 ( 2.4 × 10 −14 W/m 2 ) in the 2–10 keV X-ray band, for a "crab ...
The pulsar and its neutron star companion both follow elliptical orbits around their common center of mass. The period of the orbital motion is 7.75 hours, and the two neutron stars are believed to be nearly equal in mass, about 1.4 solar masses.