astrafoxen

Sure. It's already public domain on Wikimedia. commons.wikimedia.org/wiki/File:3I...

Considering the current circumstances on 3I/ATLAS, please do not misrepresent the image. (e.g. circling the wrong object, claiming it's aliens, etc.) So please make sure to read the description in the link.

A screenshot of my browser page, showing the Wikipedia page of 3I/ATLAS with a sick new plot that I made (uses VLT image and Seligman et al. 2025 figures!). There's a bunch of open tabs for arXiv papers on 3I/ATLAS, which I've been using to cite stuff for Wikipedia.

jamming to deltarune song remixes while fighting space misinformation :3

(I've been busy improving the 3I/ATLAS Wikipedia article..!)
en.wikipedia.org/wiki/3I/ATLAS

I would've thought that mirroring could be an issue, but multiple papers (2507.13409 Fig2, 2507.05226 Fig1) show the projected tail does point towards the Sun. Opitom et al. says the tail is foreshortened, so it's definitely an anti-tail effect from geometry. bsky.app/profile/astr...

bsky.app/profile/astr...

The near-Earth asteroid moons don't get fancy nicknames sadly... it's just Alpha, Beta and Gamma :/

(if someone does a study on asteroid 1866 Sisyphus's moon, they should call it Sisyphus Prime /ref)

Full, uncropped view of Hubble's WFC3 image of interstellar comet 3I/ATLAS.

(no worries, questions appreciated!)
3I was moving at a rate of 1.56 arcsec/minute in the sky, which translates to 39 pixels per minute in Hubble's Wide-Field Camera (aka "WFC3"). Hubble's WFC3 has a FOV of 160x160 arcsec, or 4000x4000 pixels; I had to crop out a lot. Full image looks like this:

The stationary lines in the background are stars—Hubble was following the movement of 3I/ATLAS while it was taking the image, so stars appear trailed or motion blurred. The big stationary thing on the upper right is a very bright star. Cosmic rays are the white dots that flicker between images.

Hmm in that case that's almost borderline on the ability to see 3I's coma. I can't confidently say that's a detection or not unless you could do some more advanced analysis like comparing the comet's radial brightness profile to that of a stationary star. But anyways, your image is nice! :)

Maybe? The coma/tail should be parallel to the 3I's direction of motion, and your stack of 3I seems to show a slight elongation in that direction. What's the pixel scale (arcsec/px) here? 3I's coma should be up to 4-5 arcsec in diameter, so you might be able to see it.

Here's the new IAU Small Body Nomenclature bulletin containing 109 new names for minor planets! www.wgsbn-iau.org/files/Bullet...

Size comparison of the 16 largest trans-Neptunian objects, including the dwarf planet Pluto and the upper left corner. Each object is represented as a colored circle, with accurate scale relative to each other. Top row: Pluto, Eris, Haumea, Makemake, Gonggong Middle row: Quaoar, Orcus, Sedna, Salacia, Mani, Aya Bottom row: Varda, 2013 FY27, Achlys, Ixion, Ritona This image was modified from the original by Lunathesilly on Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Trans-Neptunians_Size_Albedo_Color.svg

Quick aside, I'm really happy that more big TNOs/dwarf planet candidates got official names this year, 2 decades after their discovery :D

2005 RN43 → "Ritona" today
2003 AZ84 → "Achlys" on June 30
2002 AW197 → "Aya" on June 30
2002 MS4 → "Máni" on June 9

(size comparison by Lunathesilly on wiki)

Sweet! I wonder how this compares to Hopkins et al.'s prediction of a "water ice-rich composition" for 3I/ATLAS and Galactic thick disk ISOs? arxiv.org/pdf/2507.05318

Spectroscopic Characterization of Interstellar Object 3I/ATLAS: Water Ice in the Coma We present optical and near-infrared spectroscopy of the interstellar object 3I/ATLAS, obtained with Gemini-S/GMOS and NASA IRTF/SpeX on 2025 July 5 and July 14. The optical spectrum shows a red slope...

Today on the #arXiv:

Yang et al. 2025, "Spectroscopic Characterization of Interstellar Object #3I/ATLAS: Water Ice in the Coma" - arxiv.org/abs/2507.14916

#3I is putting out water ice along with organic and silicate dust.

As expected for a comet.

I see. I wasn't aware of that, thanks for telling me!

3I/ATLAS (big gray fuzzy blob at center) as seen by the Hubble Space Telescope. This image was created by combining 4 Hubble images with median blending. This isolates the comet from the background stars and noise.

And here is a 4-frame median stack of the 16 and 18 UTC image pairs:

Two hours later (Jul 21, 18:05 UTC), Hubble took some more images of 3I/ATLAS!

BTW, you can download and see the calibrated (DRZ) Hubble images yourself at mast.stsci.edu/search/ui/#/.... You'll need a program that can open FITS-format images (like Aladin, FITSviewer, etc. Go wild with em)

Yep! Right now the tail is being viewed at a head-on perspective from Earth (& Hubble), so the tail's behind the nucleus and is foreshortened (said in arxiv.org/pdf/2507.05226). Sorta like looking directly down at the tip of a cone. The tail looks like it's pointed toward the Sun, but it's geometry.

Ahh got it!

I'm not sure which right hand corner you're talking about. But if you're talking about those small white specks with upper-right-pointing tails, those are cosmic rays. 3I/ATLAS's tail looks stubby and diffuse, from what I can tell from playing around with the contrast.

A single image of 3I/ATLAS made by combining the two frames with darken blending. This removes cosmic rays and stars and isolates the comet, whose appearance doesn't change between the image.s

Hubble image centered on 3I/ATLAS

And a couple more processings I did with the calibrated Hubble images:

Hubble Space Telescope images of interstellar comet 3I/ATLAS are out! These were taken 5 hours ago. Plenty of cosmic rays peppering the images, but the comet's coma looks very nice and puffy. Best of luck to the researchers trying to write up papers for this... archive.stsci.edu/proposal_sea... 🔭

Logos-Zoe: a triple or quadruple trans-Neptunian system? → archive.stsci.edu/proposal_sea...
Confirming distantly-active long period comets on retrograde orbits >20 au → archive.stsci.edu/proposal_sea...
Probing the TNO Density Transition with Mid-Size 2013 FY27 → archive.stsci.edu/proposal_sea...

A Search For The Moons of Mid-Sized TNOs → archive.stsci.edu/proposal_sea...
This proposal will observe *98* mid-sized TNOs and dwarf planet candidates sometime in 2026!? And that includes 2012 VP113, 2014 UZ224, 2014 EZ51, 2018 VG18, 2021 DR15, 2021 LL37, etc.!!
I'm absolutely hyped for this one!

Geophysical Characterization of the Distant Ocean World Makemake → archive.stsci.edu/proposal_sea...
2014 WC510: A second trans-Neptunian triple? → archive.stsci.edu/proposal_sea...
Probing the Interior of the Dwarf Planet Haumea → archive.stsci.edu/proposal_sea...

A screenshot showing some of the new Cycle 33 Hubble Space Telescope proposals for observing trans-Neptunian objects (TNOs), all of them with Benjamin Proudfoot as the Principal Investigator. From top to bottom, their titles are: 1) HST Cycle 33 proposal 18002: Probing the Interior of the Dwarf Planet Haumea 2) HST Cycle 33 proposal 18005: 2014 WC510: A second trans-Neptunian triple? 3) HST Cycle 33 proposal 18006: Geophysical Characterization of the Distant Ocean World Makemake 4) HST Cycle 33 proposal 18010: A Search For The Moons of Mid-Sized TNOs

OH MY GOD
NEW HUBBLE CYCLE 33 PROPOSALS ARE OUT AND THERE'S SO MANY UPCOMING TNO OBSERVATIONS

NSF-DOE Vera C. Rubin Observatory Observations of Interstellar Comet 3I/ATLAS (C/2025 N1) We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS), with the NSF-DOE Vera C. Rubin ...

It's paper day! The first science paper with data from @vrubinobs.bsky.social's survey camera, the mighty LSSTCam, is a VERY quick turnaround of Rubin's observations thus far of interstellar comet 3I/ATLAS. ☄️
Chandler et al., submitted 🔭
A 🧵

NSF-DOE Vera C. Rubin Observatory Observations of Interstellar Comet 3I/ATLAS (C/2025 N1) We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS), with the NSF-DOE Vera C. Rubin ...

New paper on arXiv, analyzing Rubin Observatory data of interstellar object 3I/ATLAS. This is the first science paper with data from LSSTCam!!!!!

arxiv.org/abs/2507.13409

Oh wait that person got banned LMAO
But yeah the talk page was essentially a 4v1 argument, so nothing to worry about haha :p

I was on that 3I talk page with a few others. It's mainly us trying to inform other unsuspecting users why Loeb isn't reliable, but there's this one single person (one of the people who added Loeb to the article) who keeps dodging our questions... luckily we just ignored him and he stopped editing.

Noted. Thanks for telling me, I didn't know that was the case.