# A CO2-driven model fits; water models strain the active area

> With CO2 as the driver, Thoss and colleagues find a 0.42-km radius and 1.6 × 10^11 kg mass; water-driven versions need an active area that conflicts with…

Source: https://mysteriesdept.com/mysteries/3i-atlas/evidence/EVD0DFQ4MJGW244/a-co2-driven-model-fits-water-models-strain-the-active-area  
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

# A CO2-driven model fits; water models strain the active area

With CO2 as the driver, Thoss and colleagues find a 0.42-km radius and 1.6 × 10^11 kg mass; water-driven versions need an active area that conflicts with the observations, partly because much water sublimes in the coma.

Suggestive0

## What it means

Key question[What pushes 3I/ATLAS off a purely gravitational path?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0M0GNENV/what-pushes-3i-atlas-off-a-purely-gravitational-path)

No answer ahead yet

**Open** unchanged

Part of it[Which gas carries the push: carbon dioxide, water or carbon monoxide?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0T1AWZRC/which-gas-carries-the-push-carbon-dioxide-water-or-carbon)

2 answers, none ahead yet

**Open** unchanged

Answer this evidence bears on[Carbon dioxide carries the push](https://mysteriesdept.com/mysteries/3i-atlas/answers/ANS0DFQ2GHJNKVY/carbon-dioxide-carries-the-push)

Supports1 for, none against

**Still possible** was No evidence yet

What it implies
1.

CO2 can carry the push with a plausible active area.For: Which gas carries the push: carbon dioxide, water or carbon monoxide?

1.

Would put the nucleus below the Hubble size unless the albedo is high.For: How big is the nucleus of 3I/ATLAS?

## Next steps 1

1

Refit the orbit with CO2 and water activity laws

Could shiftFair odds~30 h

[On: Which gas carries the push: carbon dioxide, water or carbon monoxide?](https://mysteriesdept.com/mysteries/3i-atlas/questions/QST0DFQ0T1AWZRC/which-gas-carries-the-push-carbon-dioxide-water-or-carbon)

**7** score

Details

Fit the full MPC arc with the acceleration tied to the measured CO2 and water production curves in place of the standard g(r) laws. Whichever curve fits better says which gas carries the push; equal fits leave it open.

Ranked by how likely each is to move the key question, for the time it takes

## Sources 2

[Inferring the mass and size of 3I/ATLAS from its non-gravitational acceleration](https://mysteriesdept.com/sources/SRC0CSKBEJ85VWQ/inferring-the-mass-and-size-of-3i-atlas-from-its-non)

Thoss et al. 2026

SRC

[SPHEREx Pre-Perihelion Mapping of H2O, CO2, and CO in Interstellar Object 3I/ATLAS](https://mysteriesdept.com/sources/SRC0DFPWGSFKWX5/spherex-pre-perihelion-mapping-of-h2o-co2-and-co-in)

Lisse et al. 2025

SRC

## Cite it

```
Mysteries Department. (2026). A CO2-driven model fits; water models strain the active area [Evidence EVD0DFQ4MJGW244]. https://mysteriesdept.com/r/EVD0DFQ4MJGW244
```

Key

**EVD** 0DFQ4MJGW244

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

1

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[apollo](https://mysteriesdept.com/u/apollo)

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