Recently, Ph.D. GUO Yunlang, from Nanjing University, and Prof. WANG Bo, from Yunnan Observatories of the Chinese Academy of Sciences, investigated the formation of the shortest orbital period black widow PSR J1953+1844 (M71E) through ultracompact X-ray binaries with He star companions. This work was published in Monthly Notices of the Royal Astronomical Society.
Millisecond pulsars (MSPs) are old radio pulsars with spin periods < 30 ms. They are proposed to be formed from the evolution of low/intermediate-mass X-ray binaries. They are important objects for revealing the evolutionary history of close neutron star (NS) binary systems, such as the decay of the surface magnetic field of NSs, the magnetic braking, the NS equation of state and the accretion efficiency.
Recently, a BW pulsar, PSR J1953 +1844 (i.e. M71E) was discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) during the FAST Galactic Plane Pulsar Snapshot survey. The orbital period of 53 min from the archival data of FAST globular cluster pulsar survey. The further timing shows that the mass of its companion is ～ 0.01 solar mass derived from the mass function. Such short orbital period indicates that PSR J1953 +1844 may originate from ultracompact X- ray binaries (UCXB).
The researchers explored the origin of PSR J1953+1844 by considering the evaporation process based on the He star donor channel, where the binaries could experience the UCXB phase. Our simulations reproduce the characteristics of PSR J1953+1844, i.e. the low companion mass and the short orbital period. Thus, this work provides an alternative way for the origin of PSR J1953+1844, and implies that this object may originate from an UCXB. In addition, PSR J1953+1844 may evolve into an isolated MSP eventually, and this object provides a support for the He star donor channel.
This work proposed an alternative formation channel for producing the shortest orbital period black widows PSR J1953+1844 (M71E).
Contact:
GUO Yunlang
Yunnan Observations, CAS
yunlang@nju.edu.cn
