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. Author manuscript; available in PMC: 2021 Dec 1.
Published in final edited form as: Nat Geosci. 2021 May 10;14:369–376. doi: 10.1038/s41561-021-00733-0

Figure 4: Relative distribution of nitrogen in the constituent reservoirs of protoplanetary bodies as a function of oxygen fugacity.

Figure 4:

At any given fO2, the proportion of N in the (a) atmospheric reservoir decreases, while it increases in the (b) magma ocean and (c) core reservoir with increase in the size of the rocky body. Assuming these bodies had similar densities, their N partial pressure (pN) correlate with their radius. Therefore, large bodies have higher pN (d) resulting in a higher amount of N dissolving into their MOs and cores. As N solubility in the MO decreases and the siderophile character of N increases with increasing fO2, the proportion of N in the MO decreases and proportion of N in the atmosphere and/or core increases. Consequently, for rocky body differentiation at logfO2> IW–4, asteroid-sized (Vesta (0.04 R⊕) and intermediate-sized (0.12 R⊕)) bodies have almost all of their N in the atmospheric reservoir, while for planetary embryo-sized bodies (Moon (0.27 R⊕) and Mars (0.53 R⊕)) the cores become an important reservoir for N storage. The fO2s of core-mantle differentiation in panel (b) are compiled in Supplementary table 6.