Protosolar Nitrogen

Abstract

We have derived a value of 15N/14N = img1.gif x 10-3 in the Jovian atmosphere using data from the Galileo Probe Mass Spectrometer. Adopting this as the average value for nitrogen in the solar nebula leads to a consistent interpretation of other measurements of nitrogen isotopes in the solar system, once nuclear evolution in the Galaxy and ion-molecule reactions in the interstellar medium are taken into account. The result confirms the assumption that atmospheric nitrogen on Earth was not delivered as N2 but that N2 was the dominant form of nitrogen in the solar nebula.