A new pulsar, designated as PSR J1617−2258A, has been discovered in the Ball cluster of NGC 6093. The findings were published in a scientific article on February 13 on the ARXIV Preprint server.
Pulsars are highly magnetic rotating neutron stars that emit electromagnetic radiation, often in the form of radio waves. Millisecond pulsars (MSP) are a special type of pulsars that rotate with periods of less than 30 milliseconds. They are believed to form in double systems, where one star transforms into a neutron star and accelerates due to the accretion of material from its companion.
Ball clusters, due to their high star density, serve as ideal environments for the formation of MSPs. The high density allows neutron stars to acquire companions through interactions in binary systems.
The GCGPS project aims to search for MSPs in galactic ball clusters using the modernized Giant Metrewve Radio Telescope (UGMRT). The telescope’s unique feature is its coverage of low radio frequencies (300-850 MHz), which helps in effectively identifying sources with a steep spectral index characteristic of MSPs.
The first successful discovery within the GCGPS project is PSR J1617–2258A, a millisecond pulsar in a double system with a rotation period of about 4.32 milliseconds and a 66.8 PC/CM³ dispersion measure. This pulsar is located in the NGC 6093 cluster and marks the first pulsar found in this cluster.
Research conducted on PSR J1617–2258A revealed that its orbital period is approximately 18.94 hours with an eccentricity of 0.54, making it one of the most compact and eccentric double MSP systems. The pulsar’s mass is estimated to be no more than 1.6 solar masses, while its companion’s minimum mass is around 0.07 solar masses, totaling approximately 1.67 solar masses.
Scientists believe that PSR J1617–2258A is most likely a MSP paired with a white dwarf composed of helium.