American Astronomical Society, United States Of America, 1 - 04 January 2011, vol.43
Low mass X-ray binaries that show thermonuclear X-ray bursts are excellent targets for constraining the equation of state of neutron star matter. We make use of time resolved, high count rate X-ray spectra to measure the Eddington limit and the apparent radii of neutron stars. I will discuss how these spectroscopic observations have enabled the measurement of the masses and radii of the neutron stars in several low mass X-ray binaries. I will also show how these measurements led to the first significant constraints on the equation of state of the neutron star matter.