# Hui 2026: Nucleus and Postperihelion Activity of Interstellar Object 3I/ATLAS Observed by Hubble Space Telescope

> Man-To Hui, David Jewitt, Max J. Mutchler et al., 2026. 2 records on Mysteries Department cite it. The measured size of 3I, which rules out the earlier…

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[Sources](https://mysteriesdept.com/sources)[1I/'Oumuamua](https://mysteriesdept.com/mysteries/oumuamua)Hui 2026

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# Nucleus and Postperihelion Activity of Interstellar Object 3I/ATLAS Observed by Hubble Space Telescope

Man-To Hui, David Jewitt, Max J. Mutchler et al., 2026. _arXiv_.

Extracts the nucleus from Hubble images of December 2025 and January 2026: an effective radius of 1.3 ± 0.2 km for a comet-like albedo, consistent with the size implied by the non-gravitational acceleration; an axis ratio of at least 2:1 if the brightness variation is rotational; faster fading after perihelion than brightening before, which is not unusual for comets.

**1I/'Oumuamua** Preprintdoi: **[10.3847/2041-8213/ae471c](https://doi.org/10.3847/2041-8213/ae471c)** Checked against the original0

## What it's used for here

The measured size of 3I, which rules out the earlier claim of a nucleus above 5 km.

## Cited by on this site 2 records

[The same group's claims for 3I/ATLAS, such as a nucleus above 5 km, were not borne out by Hubble.](https://mysteriesdept.com/mysteries/oumuamua/evidence/EVD0CSKCP3W25F8/the-same-groups-claims-for-3i-atlas-such-as-a-nucleus-above)

Evidence

EVD

[1I/'Oumuamua](https://mysteriesdept.com/mysteries/oumuamua)

The mystery article

MYS

## Cite it

```
Hui, M. T., Jewitt, D., Mutchler, M. J., Agarwal, J., & Kim, Y. (2026). Nucleus and Postperihelion Activity of Interstellar Object 3I/ATLAS Observed by Hubble Space Telescope. arXiv. https://doi.org/10.3847/2041-8213/ae471c
```

[Read it free at arxiv.org](https://arxiv.org/abs/2601.21569)

Key

**SRC** 0CSKBDTT2X79

Kind

Preprint

Rights

arXiv-nonexclusive

Kept

27 Oct 2026, for editors

Checked

Against the published original

Added by

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

The record

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