Some stuff I did for the first 3 days of @morgandenman.bsky.social's #SpacetoberChallenge! Been too busy with college so I can't do these on time blehhhh (I'll post these individually later)

(update) This teeny meter-wide asteroid C15KM95 was officially announced with the new name "2025 TF" today! minorplanetcenter.net/mpec/K25/K25... (and a neat photo of the asteroid by @filipp-romanov.bsky.social over at: bsky.app/profile/fili...) Now to wait an hour until this gets on Wikipedia...

nyoooom

Dwarf Planet #Quaoar and its moon #Weywot with #Hubble WFC3/UVIS filter F350LP. Quaoar is located in the Kuiper Belt (beyond planet Neptune). I combined different epochs and oriented them with north being up. I removed stars. The moon changed position during its orbit around the #DwarfPlanet.

My new color photographic map of Pluto is now online. Full resolution image version (~322Mpix) is available on Flickr www.flickr.com/photos/10958... PDF version (~73MB) is available here: drive.google.com/file/d/1EW-x... 🧵 1/5

ooooo hypeeee!!

Mike Kelley describes spectra of the icy surface of comet Hale-Bopp, taken at a distance of 46 AU (!!) with JWST 🔭 : similar to Water-type TNOs but with organic features

heck yeah Makemake getting that makeover from JWST! So now we have evidence of geochemical activity, a cryovolcanic hotspot, and a potential atmosphere. I swear if Makemake turns out to also have rings or a second moon, it's gonna become my 4th favorite dwarf planet

Mimas science is serious business

Today on arXiv: The recent JWST TRAPPIST-1 e papers. They are somehow not even the biggest news in the list. Today's arXiv day's absolutely stacked.

MORE DWARF PLANETS AND BIG TNOS NAMED BY THE IAU TODAY YEAHHHHH 2004 GV9 → Goibniu 2005 RM43 → Rumina 2002 UX25 & moon → Uni & Tinia * Uni is weird because it's made of holey ice less dense than water 2002 XW93 → Xewioso 2013 FY27 → Chiminigagua (named 3 weeks ago, but nobody mentioned it on bsky)

weyWHAT An unexpected occultation discovery of a potential 2nd moon or 3rd ring arc around dwarf planet Quaoar! The new moon/ring is 30±2 km wide and seems to be 5757 km from Quaoar—suspiciously close to 7:2 orbital resonance with Quaoar's big moon Weywot! iopscience.iop.org/article/10.3... ☄️

I also did a #JWST image of the TNO #Altjira that I never posted. It might be a triple system. My image processing from 18. August: commons.wikimedia.org/wiki/File:Al...

This is a trans-Neptunian object (TNO) that is a triple system. TNOs orbit beyond planet Neptune. 🔭 The source on the left is actually two objects, called Lempo and Hiisi. The object on the right is called Paha. My processing of this #JWST NIRCam image: commons.wikimedia.org/wiki/File:Le...

EEEEE LOOK AT IT :DDD

Today on interstellar comet ☄️ 3I/ATLAS, this time from our team with ESO's VLT: the coma shows rich atomic nickel! This entirely natural metal emission from grains was only recently (last 4 yrs) identified in Solar System comets, was in 2I/Borisov, & now in 3I. 🔭🧪 Rahatgaonkar et al, ApJL submitted

JWST successfully observed interstellar object (ISO) 3I/ATLAS. Interesting results. The composition of the coma could be due to a few different scenarios. Additional JWST observations of the object closer to the sun are needed. science.nasa.gov/blogs/3iatla...

oh sick JWST results on 3I/ATLAS finally dropped science.nasa.gov/blogs/3iatla... "a CO2 dominated coma, with enhanced outgassing in the sunward direction, and the presence of H2O, CO, OCS, water ice and dust. The coma CO2/H2O mixing ratio of 8.0 ± 1.0 is among the highest ever observed in a comet"

Not as exciting as aliens, but if you want to see how actual planetary scientists study interstellar objects like 3I/ATLAS, this new paper just dropped on arxiv arxiv.org/pdf/2508.15469. The SPHEREx and IRTF 🔭 data are consistent with known physics and expected chemistry. Just sayin'.

Dwarf planet #Quaoar with its moon #Weywot (small white point right side). The system orbits the sun in the #KuiperBelt beyond planet Neptune. Quaoar has rings (not seen here). 🪐🌕 🔭 #planetsci #dwarfplanet My image with #JWST, processed today: commons.wikimedia.org/wiki/File:Qu...

Dwarf planet #Eris and its moon #Dysnomia 🌕 (lower left) with #JWST. 🔭 Eris is the most massive dwarf planet in the solar system, in orbit around the sun beyond Neptune. More massive, but smaller than Pluto. #DwarfPlanet #planetsci My image processing: commons.wikimedia.org/wiki/File:Er...

oh hell yeah first we got SPHEREx discovering carbon dioxide/CO2 gas in 3I/ATLAS yesterday (spherex.caltech.edu/news/3i-atla...) and now we have reports of cyanide/CN gas in 3I/ATLAS today

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

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)

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.

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... 🔭

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

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 🧵

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

It's paper day! We report the discovery of a new high-perihelion (q=66 au) world on a Sedna-like orbit, in the FOSSIL II survey with Subaru telescope of the outer Solar System Chen et al., free to read: rdcu.be/ev6Zf 🔭🧪

3I/ATLAS now recovered back to May 22 (mag 20.5 in g) in ZTF imagery, thanks Quanzhi Ye. In the latest MPEC

Neat new paper out on 3I/ATLAS discussing its discovery, orbit, and characterization. 🔭 arxiv.org/pdf/2507.02757

It was pretty clear early on that #3I/ATLAS could be a comet. It was found at a distance comets typically are (close to Jupiter's orbit), and the brightness measurements are not matching an asteroidal object at all. Here they are plotted against an asteroid's expected brightness curve. 🧪🔭

New paper on interstellar comet #3I/ATLAS is out on arXiv! By Darryl Seligman and more. Images show a fuzzy tail, and the comet's dusty coma is similarly reddish like the other interstellar comet 2I/Borisov. arxiv.org/abs/2507.02757 ☄️🔭🧪

ATel #17264: Deep g'-band Imaging of Interstellar Comet 3I/ATLAS from the Two-meter Twin Telescope (TTT) www.astronomerstelegram.org?read=17264 -- by Miguel R. Alarcon et al.

ATel #17263: Interstellar Interloper C/2025 N1 is Active astronomerstelegram.org?read=17263 -- by David Jewitt and Jane Luu

Interstellar visitor confirmed. #A11pl3Z is now known as 3I/ATLAS. It is only the third confirmed object from beyond our solar system.

It’s offical: the Minor Planet Centre record 3I/Atlas - the third interstellar visitor detected in tge Solar System. Very tentative reports of cometary activity, much more to come minorplanetcenter.net/mpec/K25/K25...

UPDATE ON INTERSTELLAR COMET #A11pl3Z: It's OFFICIALLY LABELED 3I/ATLAS by the Minor Planet Center!!! minorplanetcenter.net/mpec/K25/K25... HUGE thank you to all the astronomers for confirming this object! The next step now is someone getting the big scopes (Hubble, JWST, etc.) to look at it! ☄️🔭🧪

Just noticed that interstellar object #A11pl3Z was just posted on the Minor Planet Center's Possible Comet Confirmation Page (PCCP). Not sure if other people have reported cometary activity since the MPC doesn't show who did, but it's something! minorplanetcenter.net/iau/NEO/pccp...

Thanks to the work of amateur and professional astronomers, the data arc on #A11pl3Z now spans from June 15 - July 2nd, 2025. New observations are rolling in. This has lowered the uncertainty of the object's orbit. The eccentricity of this new visitor is now 6.05 +/- 0.101. The highest ever found.

The designation #A11pl3Z is a temporary designation assigned by the ALTAS team when they submitted their discovery to the Minor Planet Center at Harvard - the clearing house for observations of minor planets and comets. When they publish this object, they will assign a new designation.

FACT THREAD on New Interstellar Object #A11pl3Z This story unfolded pretty fast yesterday for a few reasons. The object was discovered on July 1st UTC by the Asteroid Terrestrial-impact Last Alert System, or ATLAS team. A #NASA funded survey at the University of Hawaii. atlas.fallingstar.com 🔭🧪

Yes, to clear up confusion, we *did not* discover A11pl3Z. We only did follow-up observations to confirm it. A11pl3Z was discovered on 2025 July 1 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) based in Chile, Rio Hurtado. ATLAS also has stations in Hawaii and South Africa. (tag ☄️🔭🧪)

Since interstellar object #A11pl3Z is gaining lots of attention, I want to clear up some confusion. A11pl3Z was discovered on 2025 July 1 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) based in Chile, Rio Hurtado. ATLAS also has stations set up in Hawaii and South Africa.

I confirmed new interstellar object A11pl3Z remotely using iTelescope.Net T72 (0.51-m f/6.8 reflector + CCD) in Chile. I stacked 5x20 sec. images with Lum filter, measured the magnitude 17.5 G for 2025 07 02.315637 UT. @astrodave.bsky.social @davidbflower.bsky.social #StormHour #PhotoHour #astronomy

ANOTHER UPDATE on interstellar object #A11pl3Z: Even MORE early obs from June 14-21 were found from the Zwicky Transient Facility! Now with 18 days of data, we have a lower eccentricity of e=6.11±0.14 for A11pl3Z's hyperbolic trajectory. (Sam Deen also notes ATLAS obs from Jun 4-17, unsubmitted) 🔭☄️

Was able to get my observatory open between clouds in soupy monsoon skies to nab an image of new interstellar object #A11pl3Z discovered by the Atlas team. Exciting times in astronomy. 🔭🧪