# Shinnaka 2026: A post-perihelion constraint on the CO2/H2O ratio of interstellar comet 3I/ATLAS from [O I] forbidden lines

> Yoshiharu Shinnaka, Ko Tsujimoto, Hideyo Kawakita, 2026. 2 records on Mysteries Department cite it. Shinnaka, Y., Tsujimoto, K., Kawakita, H. et al.…

Source: https://mysteriesdept.com/sources/SRC0DFPWGSFT997/a-post-perihelion-constraint-on-the-co2-h2o-ratio-of  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

---

[Sources](https://mysteriesdept.com/sources)[3I/ATLAS](https://mysteriesdept.com/mysteries/3i-atlas)Shinnaka 2026

**0**

# A post-perihelion constraint on the CO2/H2O ratio of interstellar comet 3I/ATLAS from [O I] forbidden lines

Yoshiharu Shinnaka, Ko Tsujimoto, Hideyo Kawakita, 2026. _arXiv_.

Subaru/HDS 2026-01-07 at 2.87 au: G/R=0.339+/-0.027 (2I-like); CO2/H2O much lower than inbound JWST value; ratio fell across perihelion.

**3I/ATLAS** Preprint0

## Cited by on this site 2 records

[CO2-to-water ratio fell from 7.6 to about 0.1](https://mysteriesdept.com/mysteries/3i-atlas/evidence/EVD0DFQ3VTKN1HK/co2-to-water-ratio-fell-from-7-6-to-about-0-1)

Evidence

EVD

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

The mystery article

MYS

## Cite it

```
Shinnaka, Y., Tsujimoto, K., & Kawakita, H. (2026). A post-perihelion constraint on the CO2/H2O ratio of interstellar comet 3I/ATLAS from [O I] forbidden lines. arXiv. https://arxiv.org/abs/2603.25002
```

[Read it free at arxiv.org](https://arxiv.org/abs/2603.25002)

Key

**SRC** 0DFPWGSFT997

Kind

Preprint

Rights

arXiv-nonexclusive

Kept

2 Nov 2026, for editors

Added by

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

The record

Bibliographic records are CC0. Take this one as CSL-JSON, BibTeX or RIS.

[CSL-JSON](https://mysteriesdept.com/sources/SRC0DFPWGSFT997/a-post-perihelion-constraint-on-the-co2-h2o-ratio-of/csl.json)