Number 195 (Story #1), September 20, 1994 by Phillip F. Schewe and Ben Stein NEUTRON STAR MASSES , at least for binary systems consisting of two neutron stars, seem to lie in a relatively narrow range. Lee Samuel Finn of Northwestern (708-491-4568) has studied the observations made of four such systems and found that with high statistical certainty the eight neutron star masses all fall within a range of 1.3 and 1.6 solar masses. Finn works only with this small sample of double neutron star binaries (only a few more are known in addition to the four he considered) because their tight mutual orbit affords a more precise mass determination than for other systems---isolated neutron stars or those in orbit around white dwarfs or other stars. Finn expects that the apparent restriction in the neutron star mass range (for which there is no theoretical explanation) will help in the eventual interpretation of catastrophic events in which binary partners spiral in toward each other. Events of this type will be sought by the Laser Interferometer Gravitational Wave Observatory. (Lee Samuel Finn, Physical Review Letters, 26 September 1994.)