“Black Widow” neutron star ate its companion and was found to be the heaviest ever

A rotating neutron star periodically rotates its radio (green) and gamma-ray (magenta) beams near Arart.  A black widow pulsar heats the front side of its stellar companion to a temperature twice that of the Sun's surface and slowly evaporates it.
in great shape , A rotating neutron star periodically rotates its radio (green) and gamma-ray (magenta) beams near Arart. A black widow pulsar heats the front side of its stellar companion to a temperature twice that of the Sun’s surface and slowly evaporates it.

NASA’s Goddard Space Flight Center

Astronomers have determined the heaviest neutron star ever known, weighing 2.35 solar masses. recent paper Published in the Astrophysical Journal Letters. How did it get so big? Most likely to devour a companion star – the celestial equivalent of a black widow spider that devours its partner. This work helps establish an upper limit to how large neutron stars can form, with implications for our understanding of the quantum state of matter at their core.

Neutron stars are the remnants of supernovae. Ars as Science Editor John Timmer wrote last month,

The matter that makes up a neutron star begins as ionized atoms near the core of a massive star. Once the star’s fusion reactions stop producing enough energy to counteract the gravitational attraction, this matter contracts, experiencing greater pressure. The crushing force is enough to obliterate the boundaries between atomic nuclei, creating a giant soup of protons and neutrons. Eventually, the electrons in this region are also forced into many protons, converting them into neutrons.

This ultimately provides a force to push back against the crushing force of gravity. Quantum mechanics prevents neutrons from being captured too closely to the same energy state, and it prevents neutrons from getting any closer and therefore collapses into a black hole. But it is possible that there is an intermediate state between a blob of neutrons and a black hole, where the boundaries between the neutrons begin to break down, resulting in odd combinations of their constituent quarks.

Short of black holes, the cores of neutron stars are the densest known objects in the universe, and because they are hidden behind an event horizon, they are difficult to study. “We know roughly how matter behaves at atomic density, such as in the nucleus of a uranium atom,” Alex Filipenko said, an astronomer at the University of California, Berkeley and a co-author of the new paper. “A neutron star is like a giant nucleus, but when you have 1.5 solar masses of this stuff, which is about 500,000 Earth masses of nuclei, it’s not quite clear how they’ll behave.”

This animation shows a Black Widow pulsar with its smaller stellar companion. Powerful radiation and the pulsar’s “wind” – the outflow of high-energy particles – strongly heats the front side of the companion, evaporating it over time.

The neutron star shown in this latest paper is a pulsar, PSR J0952-0607—or J0952 for short—located between 3,200 and 5,700 light-years away from Earth in the constellation Sexton. Neutron stars are born rotating, and the rotating magnetic field emits rays of light in the form of radio waves, X-rays or gamma rays. Astronomers can see pulsars when their rays are transmitted to Earth. was J0952 Discovered in 2017 Following up on data on mysterious gamma ray sources collected by NASA’s Fermi Gamma-ray Space Telescope, thanks to the Low-Frequency Array (LOFAR) radio telescope.

Your average pulsar spins at about one revolution per second, or 60 per minute. But J0952 is spinning at 42,000 revolutions per minute, making it the second fastest known pulsar ever. The current preferred hypothesis is that pulsars of this type were once part of a binary system, gradually tearing apart their companion stars until the latter evaporated. That’s why such stars are known as Black Widow Pulsar-What call philipenko A “Case of Cosmic Gratitude”:

The evolutionary path is absolutely fascinating. Double exclamation point. As the companion star develops and becomes a red giant, the material expands to the neutron star, and it spins the neutron star. By spinning, it now becomes incredibly active, and a wind of particles begins to eject from the neutron star. That wind then collides with the donor star and begins to separate the material, and over time, the mass of the donor star is reduced to the mass of the planet, and if even more time passes, it will completely disappears from So, this is how a single millisecond pulsar can be made. They weren’t alone to begin with—they had to be in a binary pair—but they slowly evaporated out of their peers, and are now single.

This process will explain how J0952 became so heavy. And such systems are a boon to scientists like Filipenko and his colleagues who want to precisely weigh neutron stars. The trick is to find a neutron star binary system in which the companion star is small but not too small to be detected. Of the dozen or so black widow pulsars the team has studied over the years, only six met that criteria.

Astronomers measured the velocities of a faint star (the green circle) stripped of nearly its entire mass by an invisible companion, a neutron star and millisecond pulsars, which they have found to be the most massive and perhaps the upper limit of neutron stars. have set.  ,
in great shape , Astronomers measured the velocities of a faint star (the green circle) stripped of nearly its entire mass by an invisible companion, a neutron star and millisecond pulsars, which they have found to be the most massive and perhaps the upper limit of neutron stars. have set. ,

WM Keck Observatory, Roger W. Romany, Alex Filipenko

J0952’s companion star is 20 times the mass of Jupiter and is tidally locked in orbit with the pulsar. The side facing J0952 is thus quite hot, reaching a temperature of 6,200 Kelvin (10,700 °F), making it so bright that it can be seen with a large telescope.

Filipenko and others. The past four years have been spent making six observations of J0952 with the 10-meter Keck Telescope in Hawaii to capture the companion star at specific points in its 6.4-hour orbit around the pulsar. They then compared the resulting spectra with the spectra of similar stars like the Sun to determine the orbital velocity. This, in turn, allowed them to calculate the mass of the pulsar.

Finding more such systems will help clear further constraints on the upper limit of how massive neutron stars can form before collapsing into black holes, as well as win over competing theories on the nature of the quark soup at their cores. Huh. “We can continue to look for Black Widow and similar neutron stars that move even closer to the brink of a black hole,” Filipenko said, “But if we don’t find any, it strengthens the argument that 2.3 solar masses is the real limit, beyond which they become black holes.”

DOI: Astrophysical Journal Letters, 2022. 10.3847/2041-8213/ac8007 ,About DOI,

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