Turkish scientist to address neutron star mystery in astrophysics fellowship

Astrophysicist Onur Benli will explore the complex dynamics of neutron stars in new research at the University of Southampton funded by the Scientific and Technological Research Council of Turkey (TUBITAK).

The TUBITAK fellowship, which supports promising Turkish scientists by initiating international research collaborations, will study cosmic structures known as accretion discs and their subset’s peculiar properties.

Onur will work closely with Principal Research Fellow Dr Diego Altarmirano over the next year as he is embedded in Southampton’s School of Physics and Astronomy.

“At the end of their lives, massive stars collapse while their outer shells are driven away during a supernova explosion,” Onur explains. “The core settles down into an object with extreme density and magnetic fields, called a neutron star. Matter falling on to stars is termed accretion. In this project we will study the dynamics of neutron stars, the structures of diffuse material that orbit around the central body.”

A subset of accreting neutron stars, transitional millisecond pulsars (tMSPs), undergo occasional transitions between radio and X-ray states which scientists have observed are characterised by peculiar properties.

“The magnitude of the torque acting on neutron stars remains interestingly similar before and after the reversals,” Onur says. “We are aiming to explain this torque reversal phenomenon theoretically and answer a decades-old scientific question. In addition, by using a modified version of a disc model that I have previously studied, we will also predict the transitional luminosities of tMSPs, a feat that has not been correctly estimated until now. In this way, we will be able to determine the best candidates that could show transitions in future.”

Onur’s research group at Sabanci University in Turkey recently contributed to a collaborative study into unusual infrared light emissions from a neutron star which was published in the Astrophysical Journal. Onur will return to Turkey at the conclusion of his TUBITAK fellowship and intends to build on the collaboration he has established with Physics and Astronomy at the University of Southampton.