US, WASHINGTON (ORDO NEWS) — Using data obtained using a five-meter aperture spherical radio telescope (FAST), a research team led by Prof. Pan Zhicheng and Professor Li Di of the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) discovered an eclipse of a binary millisecond pulsar in the globular cluster Messier 92 (M92).
Named PSR J1717 + 4307A or M92A, it is the first pulsar known in the M92, with a rotation period of 3.16 ms and a dispersion index (DM) of 35.45 pc cm -3 . Subsequent observations showed that this binary system is in a circular orbit with an orbital period of 0.2 days and a radius of 120 thousand kilometers. A satellite is a star with a mass of 0.18 solar masses, evolving into a subgiant.
Due to the compactness of the orbit, the material from the satellite is absorbed by the pulsar. This binary system is nicknamed the Black Widow. Like this type of spider, in which females usually eat their companions, the pulsar tends to take material from its companion.
Since the discovery of the first pulsar in 1967, thousands of pulsars have been discovered in our galaxy. Although some of them are located in the galactic plane, we also observed a population of pulsars in globular clusters that revolve around the Milky Way.
These pulsars are a useful tool for studying a completely different environment: dense stellar nuclei, consisting of stars up to 10 billion years old. To date, 157 pulsars have been detected in 30 globular clusters.
The M92A pulsar was first discovered on October 9, 2017, during the commissioning of the FAST telescope. With more than double the data collection area than the Arecibo telescope in Puerto Rico, we expect more discoveries from FAST in the near future. The data will improve our understanding of the pulsar population in the Milky Way and related astrophysics, such as massive stellar evolution.
This work was published in the Astrophysical Journal Letters on March 19 and was awarded by the American Astronomical Society (AAS) on April 17, 2020.
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