(ORDO NEWS) — Astronomers have made a comprehensive study of the unusual millisecond black widow pulsar, known as PSR J0610-2100, and explained the features of its behavior.
The fastest-spinning pulsars, those with intrinsic periods of less than 30 milliseconds, are known as millisecond pulsars.
The researchers believe that these objects form in binary systems when the initially more massive component turns into a neutron star, which then spins up at high speed, accreting matter flowing onto it from the companion star.
One of the classes of extreme binary systems that include a pulsar is called “spider pulsars”. Among these objects, subclasses of “black widows” are distinguished, systems in which the companion star has an extremely small mass, less than 0.1 solar masses, and “red back spiders” if the secondary component is more massive.
Discovered in 2003, PSR J0610-2100 is a millisecond black widow pulsar with a rotation period of 3.86 milliseconds.
The companion star has a mass on the order of 0.02 solar masses and orbits the neutron star with a period of 6.86 hours. Previous observations of this system showed variability in the optical range, but did not find signs of changes in the orbital period or eclipses in the radio range.
To explain these features of the PSR J0610-2100 system, in a new study, a team led by Emma van der Vateren (Emma van der Vateren) from the Netherlands Institute for Radio Astronomy ASTRON made observations in the radio range using telescopes of the European Southern Observatory, as well as optical observations of the companion star.
Observations confirmed the absence of fluctuations in the intensity of the radiation of the system in the radio range and significant changes in the orbital period.
In addition, the observations made it possible to determine the temperature of the side of the companion star that faces the neutron star. According to the authors, this temperature is relatively small, amounting to only 2820 Kelvin.
Based on the collected data, the authors concluded that the absence of eclipses of the PSR J0610−2100 system in the radio range is explained by the fact that the low temperature of the irradiated side of the companion star, as well as the relatively low rotation speed of the pulsar PSR J0610−2100, determine the low mass loss with the pulsar wind.
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