Interstellar visitor

[gortex]

The first image and data from James Webb has finally been released.

As expected, 3I/ATLAS is outgassing as it approaches the sun, and astronomers have used the JWST and its NIRSpec instrument to identify carbon dioxide, water, water ice, carbon monoxide, and the smelly gas carbonyl sulfide in its coma.

What wasn't expected, however, was the highest ratio of carbon dioxide to water ever observed in a comet. This could reveal more about the conditions in which 3I/ATLAS formed.

The abundance of carbon dioxide in the coma of 3I/ATLAS could indicate that the interstellar comet has a heart that is intrinsically rich in carbon dioxide. This could imply that the comet contains ices that were exposed to much higher levels of radiation than comets in the solar system have been exposed to.

Alternatively, the team suggests this high carbon dioxide content could indicate that 3I/ATLAS may have formed in a specific site called the "carbon dioxide ice line" within the swirling cloud of matter, or "protoplanetary disk," that surrounded its stellar parent. This is defined as the point at which the temperature around an infant star or "protostar" falls low enough to allow carbon dioxide to change from a gas to a solid.

Furthermore, the low abundance of water vapor in the coma of 3I/ATLAS could indicate that there is something within the comet that is inhibiting heat from penetrating the icy core of the comet. This would hinder the amount of water transforming from ice into gas relative to the transformation rate of carbon dioxide and carbon monoxide.


https://www.space.com/astronomy/james-we...ed-results

    
Avi Loeb has offered his comments on the Webb data.

The CO2 mass loss amounts to the ablation of a millimeter thick layer from the surface of a 46-kilometer object over a period of a few years. In other words, a relatively thin outer layer is sufficient to maintain the observed cloud of CO2 gas around 3I/ATLAS. What lies under this outer skin remains unknown.

The high CO2 to H2O ratio is puzzling. There is only one previous comet with a similarly extreme CO2 to H2O ratio, named C/2016 R2, but its image shows a clear cometary tail that does not look anything like the plume around 3I/ATLAS. The Webb team conjectures that the anomalous composition of the gas plume surrounding 3I/ATLAS might be the result of high reflectance or reduced heat penetration through its surface. Increasing the albedo from 5% to the maximum value of 100% for a mirror, reduces the estimated diameter from 46 to 10 kilometers based on the SPHEREx data. This still poses an untenable demand on rocky material in interstellar space.

A way to resolve the discrepancy between the mass reservoir of rocks in interstellar space and the unexpected discovery of a large object, is that 3I/ATLAS was not drawn from a population of rocks on random trajectories but instead — its trajectory was designed to target the inner Solar system. This possibility is consistent with the alignment of this retrograde trajectory with the orbital plane of the planets around the Sun, a coincidence of 1 part in 500 for a random occurrence.
https://avi-loeb.medium.com/the-first-we...d89e872870