Jupiter formed as a pebble pile around the N$_2$ ice line

TL;DR

This paper investigates Jupiter's formation location and process by analyzing its nitrogen and oxygen abundances, concluding that Jupiter likely formed as a pebble pile near the N$_2$ ice line, with specific implications for its composition.

Contribution

It provides a novel analysis linking Jupiter's nitrogen enrichment and formation location, favoring pebble accretion near the N$_2$ ice line over other formation scenarios.

Findings

Jupiter's nitrogen abundance suggests accretion of N$_2$ outside or near the N$_2$ ice line.

Jupiter's oxygen abundance is predicted to be between 3.6 and 4.5 times solar.

The formation scenario favors pebble accretion at the N$_2$ ice line.

Abstract

The region around the H$_2$O ice line, due to its higher surface density, seems to be the ideal location to form planets. The core of Jupiter, as well as the cores of close in gas giants are thus thought to form in this region of the disk. Actually constraining the formation location of individual planets has proven to be difficult, however. We aim to use the Nitrogen abundance in Jupiter, which is around 4 times solar, in combination with \textit{Juno} constraints on the total mass of heavy elements in Jupiter, to narrow down its formation scenario. Different pathways of enrichment of Jupiter's atmosphere, such as the accretion of enriched gas, pebbles or planetesimals are considered and their implications for the oxygen abundance of Jupiter is discussed. The super solar Nitrogen abundance in Jupiter necessitates the accretion of extra N$_2$ from the proto-solar nebula. The only location of the disk that this can happen is outside, or just inside the N$_2$ ice line. These constraints favor a pebble accretion origin of Jupiter, both from the composition as well as from a planet formation perspective. We predict that Jupiter's oxygen abundance is between 3.6 and 4.5 times solar.