Using the Canadian Hydrogen Intensity Mapping Experiment (CHIME), astronomers have detected a new radio pulsar in a binary system with a massive nondegenerate companion star. The discovery of the pulsar, which was given the PSR designation J2108+4516, was detailed in a September 14 article on the arXiv preprint server.
Pulsars are highly magnetized, rotating neutron stars that emit a beam of electromagnetic radiation. They are usually detected as short bursts of radio emissions; however, some of them are also observed through optical, X-ray, and gamma-ray telescopes.
Today, an international team of astronomers led by Bridget C. Andersen of McGill University in Montreal, Canada, reports the discovery of a rare new type of binary pulsar, harboring a massive companion. Detection was performed using CHIME, a radio telescope with a very wide field of view, large collection area and high sensitivity over the 400–800 MHz range.
“We discovered and initially monitored PSR J2108+4516 with the CHIME telescope, using the CHIME/FRB and CHIME/Pulsar backends to acquire various types of data,” the researchers wrote in the paper.
In total, the team acquired nearly three years of near-daily CHIME/Pulsar observations of PSR J2108+4516 spanning from October 20, 2018 to September 3, 2021. Profile drifts on the pulse phase indicated that the pulsar was undergoing a significant acceleration of the orbit. with a massive binary companion.
Observations of PSR J2108+4516 revealed that it has a rotation period of about 0.58 seconds and an orbital period of 269 days. The orbital eccentricity was found to be around 0.09, and the characteristic age of the pulsar was estimated at around 2.1 million years. The surface magnetic field of PSR J2108+4516 has been measured at around 1.2 trillion Gauss.
As for the companion object, the results suggest that its mass should be between 11.7 and 113 solar masses. The study found that the companion is a bright star OBe, known as EM*UHA 138, located about 10,600 light-years away. The researchers estimate that the mass of this star is most likely between 17 and 23 solar masses.
Summarizing the results, the astronomers pointed out that PSR J2108+4516 is the sixth young pulsar with a massive nondegenerate companion detected so far.
“We presented the CHIME/FRB discovery and the 2.8-year CHIME/Pulsar synchronization of a new radio pulsar/massive star binary, PSR J2108+4516, only the 6th known such binary pulsar,” they concluded.
The authors of the paper added that PSR J2108+4516 could serve as a rare laboratory for the exploration of massive stellar winds and circumstellar disks. They propose future optical spectroscopic observations of this pulsar to determine the type of companion and whether it has a disk, as well as X-ray and gamma-ray studies to inspect the interactions between the disk and the wind.
A new millisecond pulsar discovered by astronomers
Bridget C. Andersen et al, CHIME Discovery of a Binary Pulsar with a Massive Non-Degenerate Companion. arXiv:2209.06895v1 [astro-ph.HE]arxiv.org/abs/2209.06895
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Quote: New binary pulsar detected with CHIME (2022, September 21) retrieved September 21, 2022 from https://phys.org/news/2022-09-binary-pulsar-chime.html
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