University of Virginia, College and Graduate School of Arts and Sciences

Graduate Student Thankful Cromartie Leads a Nature Astronomy Paper

September 23, 2019

UVa Astronomy graduate student Thankful Cromartie led a paper published in Nature Astronomy detailing the discovery of the most massive neutron star ever observed. This work was conducted along with her advisor Scott Ransom (of UVa and the National Radio Astronomy Observatory) and the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration. The team used pulsar timing — accounting for every rotation of dense, rapidly rotating stellar remnants — to measure the mass of J0740+6620, a 2.89-ms pulsar with a binary white dwarf companion. This work is significant because the way matter behaves (the "equation of state") deep inside the supranuclear-density interiors of neutron stars is very poorly understood. Each formulation of the equation of state dictates the mass at which the star should collapse; therefore, finding more and more massive neutron stars helps put constraints on the equation of state and improves our understanding of nuclear physics and stellar evolution. The work was covered by CNN, ABC News, USA Today, Gizmodo, Forbes, and other news sources. A summary she wrote of the paper (with a link to the original) can be found here: The NRAO press release can be found here: