1. The problem statement, all variables and given/known data An open cluster is observed to contain 1000 stars. Clusters contain many more low mass stars compared to high mass stars, reﬂecting the star formation process. This depen- dence of the number of stars formed in a given mass range is expressed in the so-called initial mass function, which turns out to be the same for different clusters. The standard initial mass function leads to 940 stars with masses less then 8 M⊙ , 53 between 8M⊙ and 40 M⊙ and 7 stars with a mass larger than > 40 M⊙ . We will assume that no further star formation will occur in this cluster during its evolution. How many neutron stars would you roughly expect to ﬁnd in the cluster? 2. Relevant equations Neutron star is 2-3M⊙ . Possibly time/Mass/Luminosity relations. 3. The attempt at a solution I am somewhat stuck here and need a prod in the right direction. The closest thing I can think of is assume an even/normal distribution, and use the fractional mass range (1M⊙ ) of the neutron star over the number of stars under 8M⊙ , i.e. 940/8. However, this seems a bit silly and unsatisfactory really. I also considered looking at the initial mass function as the question initiall states , but a brief wiki suggests that I am not suppose to know that yet, since I have never seen the equation version of it before.