SIMBAD references

We present constraints on the mass-radius relation for the neutron star in the X-ray burst source 18 by using model spectra for X-ray bursts based on the theory developed by Titarchuk 1994. Under the assumption of isotropic burst emission the derived results exclude the Stiffer equations of state of neutron star matter. The theory can be used to derive distances to X-ray burst sources from which only burst luminosities below the Eddington limit are observed. We apply it to 17 and find a distance of 7.4^+0.8_–1.1kpc, assuming similar neutron star mass and radius for 17 and 18 and a neutron star atmosphere with cosmic element abundance for 17.