She is a part of, the dead stars that have consumed most of their companion star. A nickname that refers to these which devours the male after it . Named PSR J0952-0607, it was first discovered in 2017 as a millisecond pulsar potential, ie. between 1 and 10 milliseconds. And for good reason: it spins a wonderful 707 revolutions on itself per second, which actually according to a study published in the journal and freely available, “the fastest rotating pulsar on the disk of » ! Several observing campaigns followed these first measurements, which made it possible to study the properties of this astonishing star.
It spins at the enormous speed of 707 revolutions per second
In practice, black widow spiders correspond towhich spin at astronomical speeds so that they can attract enough of their companion so that only a small fraction of solar power. Only two dozen are currently known, as they are particularly difficult to detect.
“As the companion star evolves and begins to become onethe material spreads over , and that makes the neutron star spin. As she purrs, she becomes incredibly energetic, and a of particles start to come out of the neutron. This wind then hits the donor star and begins to remove material, and over time the donor star’s mass drops to that of a planet, and if more time passes, it disappears completely. Black Widows weren’t solitary to begin with—they must have been in a binary pair—but they gradually evaporated their companions, and now they’re solitary.” explains Alex Filippenko, co-author of the study and professor emeritus of astronomy at the University of California at Berkeley.
Its companion star has shrunk to the size of a giant planet
Thus, characterizing PSR J0952-0607 was not an easy task. As the researchers explain, if it could be detected thanks to the pulsating signal emitted by its rapid rotation, however, this signal is not sufficient to characterize it. You must be able to observe your companion in visible light. But that’s the problem: she was almost completely consumed! Its mass has decreased to 20 times its massbarely 2% of the mass of !
“These planet-like objects are debris from normal stars that contributed mass andspin their pulsar companions at times of milliseconds, increasing their mass in the process”said Roger W. Romani, first author of the study and at Stanford University. It then undergoes a lock-off : since its part closest to the black widow is much more attracted than the farthest part, it rotates and simultaneously performs a trip on itself and a trip around the other star in 6.4 hours. It is this phenomenon that occurs in the case of the Pluto-Charon system, but also the Earth-Moon system!
And it is ultimately this locking that allowed its observation. Because the temperature on its face, on the neutron star side, rises to 6,200slightly more than the temperature of just allowing it to be observed with great . Thus it is I, a telescope from the eponymous observatory located on the island of Hawaii and possessing a primary 10 meters in diameter, which was facing PSR J0952-0607, located about 3,000 light-years in the direction of from . A total of six 15-minute observations have taken place over the past four years to capture the system in a specific position of doing acceptable for measurements.
The most massive neutron star observed to date
After these observations, the researchers compared the spectrum obtained with that of known stars to derive the velocityof the star, in order to finally be able to calculate the mass of the neutron star which accompanies it. They found a mass of 2.35 ± 0.17 solar masses, making it the the most massive ever observed! Above this mass, these at the extreme density could well change to . “We can continue to search for black widows and similar neutron stars that skate even closer to the edge of the black hole. But if we don’t find any, it strengthens the argument that 2.3 solar masses is the true limit, out above which they become black holes.”says A.Filippenko.
But even for such a mass, scientists wonder about the nature of the star. It corresponds to a heart ofwhich contracted in on itself while the outer layers of this same star were blown away by a violent explosion called a supernova. The heart has contracted so much that there is no longer any question this time, but of the particles that make them up, hence the term neutron star. The average density is 1017 kg/m3which is the same as that of the atomic nucleus! “We know roughly how matter behaves at nuclear densities, such as in the nucleus of a uranium atom.comments Alex Filippenko. A neutron star is like a giant core, but when you have a solar mass and a half of that stuff, or about 500,000 Earth masses of cores all hooked together, there’s no telling how they’re going to behave. »