American astronomers have announced the discovery of a neutron star pulsar PSR J0952-0607 with a record mass, which is almost 2.5 times greater than that of the Sun. Perhaps it is approaching the upper limit, after which it begins to collapse into a black hole.
The neutron star itself was discovered in 2017. PSR O 0952-0607 is located 20 thousand light years from the Sun in the constellation Sextant. It rotates rapidly and throws out narrow and powerful streams of radiation from the poles. Every 1.41 milliseconds, one of them turns out to be directed in our direction, forming a regularly flashing millisecond pulsar.
This frequency is not very characteristic of neutron stars. Astronomers have suggested that PSR O 0952-0607 has a small and dim partner, such as a brown dwarf. As a result, a neutron star with a greater mass and density pulls its matter, absorbing additional mass and increasing its rotation speed. This process must end with the death of the neutron star partner. Such pulsars are called "black widows".
Stanford University professor Roger Romani and his colleagues used the 10-meter telescope at the Hawaiian Keck Observatory. Spectrometric observations made it possible to confirm that a partner really rotates around the neutron star at a speed of about 380 km / s, and the star itself has already gained about 2.35 solar masses.
Typically, neutron stars have about 1.4 solar masses. Thus, it is the most massive neutron star ever discovered. The previous record holder was PSR J0740+6620 in the constellation Giraffe with 2.08 solar masses.
Now astronomers will probably be able to establish the mass limit at which the collapse of a neutron star begins. For non-rotating neutron stars, it is estimated at 2.01-2.16 solar masses, but for rotating ones it can be noticeably higher.
In July, Chinese experts directly measured the magnetic field of J0243.6+6124 using the Hard X-ray Modulation Telescope orbital X-ray observatory. It turned out to be the strongest magnetic field ever found in the Universe by direct measurements. Astronomers estimated the induction of this field at 1.6 * 109 T.
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