Using the Canadian Hydrogen Intensity Mapping Experiment (CHIME), astronomers have detected a new radio pulsar in a binary system with a non-degenerate massive companion star. The discovery of the pulsar, which has been named PSR J2108+4516, was detailed in a paper published on September 14 on the arXiv pre-print server.
Pulsars are strongly magnetized, rotating neutron stars emitting a beam of electromagnetic radiation. They are usually detected as short bursts of radio emission; however, some of them are also observed through optical, X-ray, and gamma-ray telescopes.
Now, an international team of astronomers led by Bridget C. Andersen of McGill University in Montréal, Canada, reports the discovery of a rare new type of binary pulsar that hosts a massive companion. The detection was made using CHIME, a radio telescope that possesses a very wide field of view, a large collection area and high sensitivity in the 400-800 MHz range.
“We initially discovered and monitored PSR J2108+4516 with the CHIME telescope, using the CHIME/FRB and CHIME/Pulsar backends to obtain different types of data,” the researchers wrote in the paper.
In total, the team obtained almost three years of near-daily CHIME/Pulsar observations of PSR J2108+4516, extending from 20 October 2018 to 3 September 2021. Derivations of the profile over the pulse phase indicated that the pulsar experiences significant acceleration from orbit. with a massive binary companion.
Observations of PSR J2108+4516 have shown 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 at a level of about 0.09, and the characteristic age of the pulsar was estimated to be about 2.1 million years. The surface magnetic field of PSR J2108+4516 has been measured to be about 1.2 trillion Gauss.
When it comes to the companion object, the results suggest that its mass should be between 11.7 and 113 solar masses. The study found the companion to be a bright OBe star known as EM* UHA 138, located about 10,600 light-years away. 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 non-degenerate massive companion detected so far.
“We have presented the CHIME/FRB discovery and 2.8-year CHIME/Pulsar synchronization of a new radio pulsar/massive star binary, PSR J2108+4516, only the sixth such binary pulsar known,” they concluded.
The authors of the paper added that PSR J2108+4516 can serve as a rare laboratory for exploring massive stellar winds and circumstellar disks. They propose future optical spectroscopic observations of this pulsar to determine the type of companion and investigate whether it has a disk, as well as X-ray and gamma-ray studies to inspect disk-wind interactions.
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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Citation: A new binary pulsar detected with CHIME (2022, September 21) retrieved on September 21, 2022 from https://phys.org/news/2022-09-binary-pulsar-chime.html
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