# After perihelion the metals follow CO

> From December 2025 to January 2026 the nickel and iron in 3I's coma followed the correlation between metals and CO seen in Solar System comets, and…

Source: https://mysteriesdept.com/mysteries/3i-atlas/evidence/EVD0DFQ46MX9MYT/after-perihelion-the-metals-follow-co  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[3I/ATLAS](https://mysteriesdept.com/mysteries/3i-atlas)Evidence

Evidence · 3I/ATLAS

# After perihelion the metals follow CO

From December 2025 to January 2026 the nickel and iron in 3I's coma followed the correlation between metals and CO seen in Solar System comets, and outbound the metals declined more slowly, as expected for carbonyls from centimetre depths.

Suggestive0

## What it means

Key question[What is 3I/ATLAS made of, and why is its chemistry so unlike a Solar System comet's?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0HS0K7SD/what-is-3i-atlas-made-of-and-why-is-its-chemistry-so-unlike)

No answer ahead yet

**Open** unchanged

Part of it[Why did nickel vapour appear around 3I/ATLAS without iron, so far from the Sun?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0SJDC3TY/why-did-nickel-vapour-appear-around-3i-atlas-without-iron-so)

2 answers, none ahead yet

**Open** unchanged

Answer this evidence bears on[Metal carbonyls sublimating from the nucleus](https://mysteriesdept.com/mysteries/3i-atlas/answers/ANS0DFQ187PJFP2/metal-carbonyls-sublimating-from-the-nucleus)

Supports2 for, none against

**Still possible** unchanged

What it implies
1.

Ties the metals to CO, the gas carbonyls carry.For: Why did nickel vapour appear around 3I/ATLAS without iron, so far from the Sun?

## Sources 2

[Origin and evolution of NiI and FeI in the coma of the interstellar comet 3I/ATLAS throughout its trajectory](https://mysteriesdept.com/sources/SRC0DFPWGSFSQNQ/origin-and-evolution-of-nii-and-fei-in-the-coma-of-the)

Hutsemékers et al. 2026

SRC

[Post-perihelion Coma Composition of the Interstellar Comet 3I/ATLAS from Optical Spectroscopy](https://mysteriesdept.com/sources/SRC0DFPWGSFX1HR/post-perihelion-coma-composition-of-the-interstellar-comet)

Zhao et al. 2026

SRC

## Cite it

```
Mysteries Department. (2026). After perihelion the metals follow CO [Evidence EVD0DFQ46MX9MYT]. https://mysteriesdept.com/r/EVD0DFQ46MX9MYT
```

Key

**EVD** 0DFQ46MX9MYT

Kind

Evidence

Tier

Suggestive

Found in

[Session 1](https://mysteriesdept.com/mysteries/3i-atlas/sessions/SES0DFQC03S98K5/session-1-3i-atlas-opened-the-literature-to-november-2026) · 2 Nov 2026

Version

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