The statistics of masses of neutron stars, and it turns out that the couple which was discovered by Taylor have the biggest neutron star masses that are known. One is 1.44 [solar masses], so the masses in the other is, I don't know, 1.42 or something like that. Most of the neutron stars whose mass has been measured are in the range of 1.3, and as far as I am aware there is no neutron star of less than 1.3. Well, maybe 1.2-something.

Now why is that so? I believe that this is... comes from the way neutron stars are produced. They come about by the collapse of a supernova and that collapse occurs when the center part of the star, the part which has been converted into nickel, when that gets bigger then the Chandrasekhar Limiting Mass, which is about 1.4, 1.5 solar masses. So this explains, I believe, why neutron stars don't have any smaller masses.