# Nickel from 3.1 au, iron only inside 2.6 au

> VLT spectra show neutral nickel at every epoch from 3.14 au and iron only inside 2.64 au, with the nickel-to-iron ratio falling from extreme to normal…

Source: https://mysteriesdept.com/mysteries/3i-atlas/evidence/EVD0DFQ4JNJ6RZ0/nickel-from-3-1-au-iron-only-inside-2-6-au  
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

# Nickel from 3.1 au, iron only inside 2.6 au

VLT spectra show neutral nickel at every epoch from 3.14 au and iron only inside 2.64 au, with the nickel-to-iron ratio falling from extreme to normal and total metal output at least ten times other comets'; carbonyl release fits best.

Supported0

## 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.

The metals come from a carrier that sublimates far colder than dust grains release metal.For: Why did nickel vapour appear around 3I/ATLAS without iron, so far from the Sun?

1.

One of 3I's oddest features has a known chemical route.For the key question: What is 3I/ATLAS made of, and why is its chemistry so unlike a Solar System comet's?

## Sources 3

[Pre-perihelion evolution of the NiI/FeI abundance ratio in the coma of the interstellar comet 3I/ATLAS. From extreme to normal](https://mysteriesdept.com/sources/SRC0DFPWGSFD45Q/pre-perihelion-evolution-of-the-nii-fei-abundance-ratio-in)

Hutsemékers et al. 2025

SRC

[Spatial Profiles of 3I/ATLAS CN and Ni Outgassing from Keck/KCWI Integral Field Spectroscopy](https://mysteriesdept.com/sources/SRC0DFPWGSFD4B9/spatial-profiles-of-3i-atlas-cn-and-ni-outgassing-from-keck)

Hoogendam et al. 2025

SRC

[Very Large Telescope Observations of Interstellar Comet 3I/ATLAS. II. From Quiescence to Glow: Dramatic Rise of Ni I Emission and Incipient CN Outgassing at Large Heliocentric Distances](https://mysteriesdept.com/sources/SRC0DFPWGSF1VED/very-large-telescope-observations-of-interstellar-comet-3i)

Rahatgaonkar et al. 2025

SRC

## Cite it

```
Mysteries Department. (2026). Nickel from 3.1 au, iron only inside 2.6 au [Evidence EVD0DFQ4JNJ6RZ0]. https://mysteriesdept.com/r/EVD0DFQ4JNJ6RZ0
```

Key

**EVD** 0DFQ4JNJ6RZ0

Kind

Evidence

Tier

Supported

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

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