Excess N-15 in the Martian atmosphere and cosmic rays in the early solar system

Viking 1 and 2 observations of the Martian atmosphere have revealed an excess of N-15 over N-14 on the order of 3.5 x 10 to the 19th atoms/sq cm. Attention is given to a possible mechanism for the origin of the excess, i.e., cosmic rays from two of the eleven unidentified gamma ray sources reported by the COS B group, CG135+1 and CG189+1. The sources have been identified as belonging to the W3 star cluster, which is described as similar to the cluster out of which the solar system was born. Thus, intense gamma ray flux in the early solar system may account for the N-15 excess observed on Mars.