Because of its highly elliptical orbit, and massive companion, this system is likely the result of an exchange of partners: following a ‘close encounter’.
Millisecond pulsars are amongst the most extreme objects in the universe. They are extremely compact stars mainly made up of neutrons and have hundreds of thousands of times the mass of the Earth is a sphere with a diameter of about 24 km.
Recently, a group of astronomers has discovered 8-millisecond pulsars located within globular clusters. This discovery was made using the MeerKAT radio telescope, and it comes from the synergic work of two international collaborations, TRAPUM and MeerTIME.
Professor Ben Stappers from The University of Manchester said, “It is fascinating exciting to see the potential for finding a large number of new millisecond pulsars in Globular Clusters using the excellent MeerKAT telescope. It is also a preview of what will be possible with the Square Kilometre Array telescope for which MeerKAT is one of the precursors.”
Lead author Alessandro Ridolfi, a post-doctoral research fellow at INAF and MPIfR, said: “We directed the MeerKAT antennas toward 9 globular clusters, and we discovered new pulsars in 6 of them!” Five of these new pulsars orbit around another star, and one of these, named PSR J1823-3021G, is particularly interesting: Because of its highly elliptical orbit, and massive companion, this system is likely the result of an exchange of partners: following a ‘close encounter’: the original partner was expelled and replaced by a new companion star.”
Tasha Gautam, a doctoral researcher at the MPIfR in Bonn and co-author of the paper, explains: “This particular pulsar could have a high mass, more than two times the mass of the Sun, or it could be the first confirmed system formed by a millisecond pulsar and a neutron star. If confirmed by current additional observations, this would make this millisecond pulsar a formidable laboratory for studying fundamental physics.”
- A Ridolfi et al. Eight new millisecond pulsars from the first MeerKAT globular cluster census. DOI: 10.1093/mnras/stab790