Molecular oxygen in comet’s atmosphere not created on its surface

Scientists have found that molecular oxygen around comet 67P is not produced on its surface, as some suggested, but maybe from its body.

Comet 67P. Credit: ESA
Comet 67P. Credit: ESA

The European Space Agency’s Rosetta spacecraft escorted comet 67P/Churyumov–Gerasimenko on its journey around the sun from August 2014 – September 2016, dropping a probe and eventually crashing onto its surface.

At the point when the comet is sufficiently close to the sun, the ice on its surface ‘sublimes’ – changes from strong to gas – shaping a gas climate called a coma. Investigation of the coma by instruments on Rosetta uncovered that it contained not just water, carbon monoxide, and carbon dioxide, as foreseen, yet in addition atomic oxygen.

Sub-atomic oxygen is two oxygen particles consolidated, and on Earth, it is fundamental forever, where it is created by photosynthesis. It has been beforehand recognized around a portion of the cold moons of Jupiter, yet it was not anticipated that would be found around a comet.

The Rosetta science team originally reported that the oxygen was most likely from the comet’s main body or nucleus. This meant it was ‘primordial’ – that it was already present when the comet itself formed at the beginning of the Solar System 4.6 billion years ago.

One gathering of outside analysts anyway recommended there may be an alternate source for molecular oxygen at comets. They had found another approach to deliver sub-atomic oxygen in space activated by lively particles – electrically charged molecules. They suggested that responses with vigorous particles on the surface of comet 67P could rather be the source of the identified molecular oxygen.

Views of the comet form Rosetta. Credit: ESA
Views of the comet form Rosetta. Credit: ESA

Presently, individuals from the Rosetta group have analyzed the information on 67P’s oxygen in light of the new hypothesis. They suggest that the proposed mechanism for producing oxygen on the surface of the comet is not sufficient to explain the observed levels in the coma.

Lead author Mr. Kevin Heritier, from the Department of Physics at Imperial, said: “The first detection of molecular oxygen in 67P’s coma was both very surprising and exciting.”

“We tested the new theory of surface molecular oxygen production using observations of energetic ions, particles that trigger the surface processes which could lead to the production of molecular oxygen. We found that the number of energetic ions present could not produce enough molecular oxygen to account for the amount of molecular oxygen observed in the coma.”

The new investigation is predictable with group’s unique decision, that molecular oxygen is in all probability primordial. Different speculations have been proposed, and can’t yet be discounted, however the primordial hypothesis as of now fits the information best.

This is likewise bolstered by late hypotheses which returned to the development of the sub-atomic oxygen in dim mists and the nearness of sub-atomic oxygen in the early Solar System. In this model, atomic oxygen made solidified onto little residue grains. These grains gathered more material, in the end developing the comet and securing the oxygen in the core.

Scientists reported their study in the journal Nature Communications.