How fast can a neutron star spin? This is what a recent study published in The Astrophysical Journal hopes to address as an international team of more than a dozen researchers have identified one of the fastest-spinning neutron stars to date, named 4U 1820-30. Neutron stars are remnants of a collapsed supergiant star often between 10 to 25 masses of our Sun, often compressed into a radius as small as 6 miles (10 kilometers) with a mass of 1.4 Earth’s, making them one of the densest objects in the universe.
As a result of this massive collapse, their rotation speed is often significantly increased due to what’s known as the conservation of angular momentum, and this study holds the potential to better understand the formation and evolution of neutron stars throughout the cosmos. For the study, the researchers used an X-ray telescope attached to the International Space Station (ISS) to study the intriguing object.
"We were studying thermonuclear explosions from this system and then found remarkable oscillations, suggesting a neutron star spinning around its center axis at an astounding 716 times per second," said Dr. Gaurava K. Jaisawal, who is a senior researcher at DTU Space and lead author of the study. "If future observations confirm this, the 4U 1820-30 neutron star would be one of the fastest-spinning objects ever observed in the universe, matched only by another neutron star called PSR J1748–2446".
Located approximately 26,000 light-years from Earth, 4U 1820-30 is estimated to have a diameter of approximately 7.5 miles (12 kilometers) and a mass of approximately 1.4 times of our Sun. Additionally, this neutron star is part of a binary star system with the second star being a white dwarf approximately the size of Earth, and due to the extreme rotation of the neutron star, this white dwarf completes one orbit in approximately 11 minutes. Finally, the researchers also identified that the intense gravity of the neutron star is causing it to consume material from the white dwarf, resulting in massive explosions equal to an atomic blast.
"During these bursts, the neutron star becomes up to 100,000 times brighter than the Sun, releasing an immense amount of energy," said Dr. Jerome Chenevez, who is an associate professor at DTU Space and a co-author on the study. "So we are dealing with very extreme events, and by studying them in detail, we get new insights into the exiting life cycles of binary star systems and the formation of elements in the universe".
What new discoveries about neutron stars will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: Wikipedia, The Astrophysical Journal, DTU Space, Wikipedia (1)
Featured Image: Image displaying the size comparison between a neutron star and Manhattan Island. (Credit: NASA's Goddard Space Flight Center)