New millisecond pulsar M53E discovered

The pulsar is located in the star cluster M 53, 58,350 light-years away.

Using the Five Hundred Meter Aperture Spherical Radio Telescope (FAST), a team of Chinese astronomers has detected a new millisecond pulsar in the globular cluster Messier 53. The finding is reported in a research paper published June 16 on the server of prepress. arXiv. Pulsars are highly magnetized rotating neutron stars that emit a beam of electromagnetic radiation. The fastest rotating pulsars, with rotation periods less than 30 milliseconds, are known as millisecond pulsars (MSPs). Astronomers assume that they form in binary systems when the initially most massive component becomes a neutron star which then rotates due to the accumulation of matter from the secondary star.

Globular clusters (GCs) are tightly packed collections of stars that orbit galaxies. They have extraordinarily dense stellar environments, making them excellent places to form x-ray binary systems of millisecond pulsars.

Located about 58,350 light-years away, Messier 53 (also known as M53 or NGC 5024) is the most distant GC with known pulsars so far. The cluster is about 12.67 billion years old, has a mass of about 826,000 solar masses, and a metallicity of -2.1, making it one of the most metal-poor GCs in the Milky Way. To date, four pulsars have been detected in Messier 53, and three of them turned out to be MSPs. Now a group of astronomers led by Yujie Lian of Beijing Normal University in China report the discovery of another MSP in this cluster. Detection was performed using the center beam of the 19-beam FAST L-band receiver. “The follow-up observation of M53 was started on November 30, 2019, as the pilot survey for the FAST GC pulsar survey and the SP2 4 project (Pan et al. 2021),” the researchers wrote in the paper.

The newly discovered pulsar was given the designation PSR J1312+1810E (or M53E). It has a spin period of approximately 3.97 milliseconds and a dispersion measurement of approximately 25.88 pc/cm3. The orbital period of M53E was found to be 2.43 days. The companion object in the system is likely a white dwarf with an estimated mass of at least 0.18 solar masses. The strength of M53E’s surface magnetic field was measured to be no more than 140 million Gauss, and the pulsar’s characteristic age was calculated to be more than 13 billion years.