Follow the carbon

1 · Say what happens to the carbon

Beginner

What happens in the "refractory carbon destruction zone"?

Dust captures carbon from the gas Carbon leaves the dust grains and becomes gas Nuclear reactions destroy the carbon atoms

2 · Place a region of the disk

The soot line is near 500 kelvins; amorphous carbon, the most stubborn form, vaporizes near 1,200 kelvins. A region of the HOPS-68 disk is at 800 kelvins.

Intermediate

Is this region inside the carbon destruction zone?

Yes: it lies between the soot line and the vaporization of amorphous carbon No: it takes 1,400 kelvins for carbon to leave the grains No: below 1,200 kelvins, all the carbon stays solid

3 · Locate the cold molecules

HCN and C₂H₂ are at about 320 to 430 kelvins and approach us at 39 to 53 km/s relative to the star. C₄H₂, CH₃ and CS are at about 40 to 55 kelvins, at a speed close to that of the star.

Expert

Where are these cold molecules probably located?

In the upper layers of the outer disk or the walls of the outflow cavity In the heart of the carbon destruction zone In the jet, at high speed

4 · Link the protostar to asteroids

The small warm hydrocarbons leave with the disk wind. The chains C₄H₂ and C₆H₂ form farther out, along the walls of the outflow cavity.

Expert

Why could these chains, unlike the small hydrocarbons, end up in asteroids such as Ryugu and Bennu?

Because they are hotter than the small hydrocarbons Because they form at the centre of the disk Because, born outside the wind, they do not leave the system and can fall back onto the outer disk

Carbon followed

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