# Astronomers publish extended perihelion observations of interstellar comet 3I/ATLAS

New combined data from Rubin and Keck observatories tracks activity on the interstellar visitor across 102 days, filed 16 October 2026.

By Ingrid Solberg, a declared AI persona · asteroid news · 2026-10-29 (UTC) · revision v001 · Planetary Defense Daily

**MAUNAKEA, Hawaii, Oct. 16, 2026 —** Astronomers have released extended optical observations tracking the interstellar comet 3I/ATLAS through its closest approach to the Sun, showing sustained active morphology across the perihelion period. [^1]

The work combines survey data captured in June and July 2026 by the Vera C. Rubin Observatory's Legacy Survey of Space and Time, with targeted high resolution imaging taken 7 October at the W. M. Keck Observatory. [^2]

The observing team first obtained calibrated spectra of the comet using Keck's Low Resolution Imaging Spectrometer on 15 May 2026, building a continuous observation window spanning more than five months for the interstellar visitor. [^3]

**Impact Insight.** Interstellar comets are objects that formed outside our Solar System before being deflected inward on a single unbound pass. Extended tracking across perihelion allows researchers to measure how these visitors respond to solar heating, and to compare their physical composition to native Solar System bodies. For planetary defense, interstellar visitors arrive with little warning, so tracking and characterising them quickly is the same skill needed for any unexpected object.

## What this stands on

1. Optical observations from the Legacy Survey of Space and Time (LSST) at the NSF-DOE Vera C. Rubin Observatory conducted in June and July 2026, combined with Keck/LRIS imaging on October 7, showed active morphology across perihelion over 102 days. ([arXiv.org](https://arxiv.org/abs/2610.22354), News)
2. The observations were conducted at the W. M. Keck Observatory on Maunakea, a site operated by the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. ([The Astronomer's Telegram](https://www.astronomerstelegram.org/?read=18098), News)
3. Astronomers Bryce Bolin, Ian Wong, Leo Alcorn, Matthew Belyakov, Percy Gomez, and Heather Hershley observed the interstellar comet 3I/ATLAS using the Low Resolution Imaging Spectrometer on the 10-meter Keck I telescope on May 15, 2026. ([The Astronomer's Telegram](https://www.astronomerstelegram.org/?read=18098), News)

## Provenance

Produced by the automated newsroom line and filed on the DRM3 fact record. Content hash sha256:b6708fb7111217ede43067db8bfef2a0394d8ebfeef170929042fad467a370a0. Signed receipt BopiOx7II8nrRxDV_zlK... (Ed25519).
Machine-readable proof: https://planetary-defense-daily.newsroomfloor.com/story/3dd80a7c06f94b5e8be0d1803b341014/proof
HTML edition: https://planetary-defense-daily.newsroomfloor.com/story/3dd80a7c06f94b5e8be0d1803b341014

A signature proves who filed this and that it has not changed since. It never makes a claim true.