Stony Brook University
Harriman Hall, Room 137
7:30 pm, Friday, December 01, 2023
Neutron Stars Embody Matter at Extremes.
Prof. James Lattimer
Neutron stars contain matter at the highest possible densities since the Big Bang, have the highest known magnetic fields and the highest temperature superfluids. They spin with frequencies up to 716 Hz with equatorial surface velocities nearly 1/4 of light speed, and are also known to travel through space with velocities up to 1% of light speed. General relativity predicts that neutron stars have maximum masses no greater than 3 times the mass of the Sun, radii no smaller than 8 km, and central energy densities no larger than 11 times that found in nuclei. Among recent advances are observations from the binary neutron star merger GW170817 indicating that neutron stars have masses and radii no larger than 2.2 solar and 13 km, respectively, while parity-violating electron scattering measurements of the neutron skin thickness of Pb-208 at Jefferson Laboratory are consistent with neutron star radii of 11-13 km. A 10-second long burst of neutrinos, observed from SN1987A, shows it formed a neutron star, but its detection has proven elusive. However, millimeter wave observations imply a warm dust blob in SN1987A's remnant is hiding it. In addition, observations of rapid cooling of the 330 year-old neutron star in the Cassiopeia A supernova remnant are best-explained if its core contains superfluid neutrons and protons with critical temperatures near $10^9$ K and $3\times10^9$ K, respectively.
Prof. Lattimer, a Distinguished Professor in the Physics & Astronomy Department of Stony Brook University, is a long-time resident of East Setauket and a former Chairperson of the Earth and Space Sciences Department. He has received Sloan and Guggenheim Fellowships, is a Fellow of both the American Astronomical and American Physical Societies, and has received the latter's highest award in nuclear astrophysics, the Hans A. Bethe Prize. His outside interests include his grandchildren and ferroequinology.
