Molecular Oxygen in Oort Cloud Comet 1P/Halley

TL;DR

This study investigates the presence of molecular oxygen in Oort cloud comet 1P/Halley, suggesting O2 is a common and abundant parent species in comets, similar to findings in Jupiter family comet 67P/Churyumov-Gerasimenko.

Contribution

It provides evidence that molecular oxygen is present in Oort cloud comets, indicating a potentially primordial origin and commonality across different comet types.

Findings

O2 production rate in Halley is approximately 3.7% of water.

O2 abundance in Halley is compatible with that in comet 67P.

O2 may be a widespread and primordial cometary species.

Abstract

Recently the ROSINA mass spectrometer suite on board the European Space Agency's Rosetta spacecraft discovered an abundant amount of molecular oxygen, O2, in the coma of Jupiter family comet 67P/Churyumov-Gerasimenko of O2/H2O = 3.80+/-0.85%. It could be shown that O2 is indeed a parent species and that the derived abundances point to a primordial origin. One crucial question is whether the O2 abundance is peculiar to comet 67P/Churyumov-Gerasimenko or Jupiter family comets in general or whether also Oort cloud comets such as comet 1P/Halley contain similar amounts of molecular oxygen. We investigated mass spectra obtained by the Neutral Mass Spectrometer instrument obtained during the flyby by the European Space Agency's Giotto probe at comet 1P/Halley. Our investigation indicates that a production rate of O2 of 3.7+/-1.7% with respect to water is indeed compatible with the obtained Halley data and therefore that O2 might be a rather common and abundant parent species.