In recent weeks we have seen the discovery of two extraordinary pulsars: one is part of a cannibalistic binary system known as the Black Widow, the other is outside the Milky Way and is exceptionally bright.
- astronomy Galaxy’s center like never seen before
- history of the universe a dying star surrounded by six rings
In recent weeks we’ve seen the discovery of two extraordinary pulsars: one part of a cannibalistic binary system known as the Black Widow, the other outside the Milky Way and exceptionally bright.
like a lighthouse
Upon exhausting their nuclear fuel, stars with a mass greater than 10 times that of the Sun explode as supernovae. The inner region, whose weight is no longer maintained by the energy of nuclear fusion reactions, collapses in on itself, leaving behind a hyperdense star known as a neutron star. these stellar debris spin very rapidly, producing periodic pulsations of radio waves, That’s why they are also called pulsars.
Pulsars are rotating stars that behave like giant magnets. Electrons subject to their very strong magnetic field (in blue in the header image) become trapped in polar regions, creating pulses during the process: very narrow jets of radio waves that behave like a beam of light from a headlamp (shown in pink). Whenever such a lighthouse directs its beam of light towards our radio telescope, we get a short burst of radiation.
Many pulsars are part of binary star systems. In this case, the pulsar’s intense gravitational field is stealing mass from its companion star as if it were eating it, which is why these binaries have come to be called black widow systems.
A team led by Kevin Burge of the Massachusetts Institute of Technology (MIT) has identified an extreme case of the Black Widow System. about this The most compact system of all known, The distance between the companion stars is so short that their orbital period is only 62 minutes, a devilishly whirling dance. The pulsar thus deposits matter on its surface and its spin speed reaches several hundred revolutions per second. Such fast moving pulsars are called millisecond pulsars.
The object, known as ZTF J1406+1222 by its coordinates in the sky, was discovered when Brugge and his colleagues were examining data obtained at the Zwicky Transient Facility (ZTF) Telescope at Palomar Observatory (San Diego, California) . A detailed study of the object, using data from the European Gaia mission, later revealed that the compact system has a third companion star describing a much broader orbit with a period of 10,000 years.
Unlike most ‘Black Widow’ binaries, this system does not emit X-rays or gamma rays, Which is surprising considering it’s such a compact object, It is advisable to continue studying all the features of this object, because it can still hide many surprises.
Extragalactic and Super Bright
Another team of astronomers led by PhD student Yuanming Wang from the University of Sydney has just published the discovery of a pulsar that is 10 times brighter than ever known (in radio waves),
This super-bright pulsar, named PSR J0523-7125, is not located in the Milky Way, but is part of the Large Magellanic Cloud, about 160,000 light-years from Earth. Of the known 3,300 pulsars, only a few are outside our galaxy, mainly in the Magellanic Clouds.
In addition to its unusual brightness, PSR J0523-7125 has a wider-than-normal radiation beam, making it particularly difficult to see. Wang and colleagues detected this by studying the polarization of the emitted radiation. Indeed, objects with strong magnetic fields, such as pulsars, emit electromagnetic waves that propagate through spaceThat is, they are circularly polarized.
The observations were made in Australia using the large ASKAP radio wave interferometer, which has the necessary equipment to measure the polarization of the received radiation, and was accomplished with the Meerkat interferometer installed in South Africa. Thus he found that the pulsar rotates at a speed of three revolutions per second.
to find out more
Burge et al’s article on ZTF J1406+1222 Black Widow System is published in Nature and can be consulted at this link.
Wang et al’s paper on the extragalactic pulsar PSR J0523-7125 is published in a recent issue The Astrophysical Journal And it is available here.
Raphael graduate He is the director of the National Astronomical Observatory (National Geographic Institute) and an academician of the Royal Academy of Doctors of Spain.
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