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astrafoxen.bsky.social
astrafoxen
@astrafoxen.bsky.social
1.2K followers 100 following 270 posts
20 - any pronouns
Astrophysics undergrad student in California (grad '27), aspiring planetary scientist. I do astronomy research on asteroids, comets and TNOs!

pfp by EchaSkqech
banner by Ian Regan
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astrafoxen.bsky.social
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)
#SpacetoberChallenge Day 1: Launch #SpacetoberChallenge Day 2: Planet (Uranus & Cordelia) #SpacetoberChallenge Day 3: Space Weather (Black Widow Pulsar)
October 6, 2025 at 8:21 PM
astrafoxen.bsky.social
(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...
October 2, 2025 at 3:53 PM
astrafoxen.bsky.social
nyoooom
tony873004.bsky.social Tony Dunn @tony873004.bsky.social · Oct 1
An #asteroid passed just 300 km above Antarctica earlier today. It was not discovered until hours after close approach.
October 2, 2025 at 12:12 AM
Reposted by astrafoxen
melina-iras07572.bsky.social
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.
A moderate bright point-source in the middle and smaller sources around them, labeled with dates.
October 1, 2025 at 11:32 AM
Reposted by astrafoxen
danielmachacek.bsky.social
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
Small preview of color photographic map of Pluto in Mollweide oblique projection. It contains one large global map with four small hemispheric maps and basic description. Full version of this map is available for download in links in the main post. Credit: NASA/JHU-APL/SwRI/Marc W. Buie/ESA/Daniel Machacek.
October 1, 2025 at 3:43 AM
astrafoxen.bsky.social
ooooo hypeeee!!
morgandenman.bsky.social Morgan Denman | Space-Focused Designer & Illustrator @morgandenman.bsky.social · Sep 23
It’s almost time for the 2025 edition of the #SpacetoberChallenge! I haven’t created an account for the challenge here on this app yet, but please still share your art here with the hashtag. I would love to see all your cosmic creations! 🧡

#SciArt #SpaceArt
Graphic showing the Spacetober challenge prompt list for 2025. The background is an orange gradient with a black box on top, with the number of each day and the corresponding prompt for each in white text on top. 1: Launch, 2: Planet(s), 3: Space Weather, 4: Moon, 5: Voyager, 6: Constellation, 7: Space Agency, 8: Propulsion, 9: Nebula, 10: Artemis II, 11: Asteroid, 12: Eclipse, 13: Near or Deep Space Network, 14: Spacecraft, 15: Black Hole, 16: Parachute, 17: Historic Person(s), 18: Mars/Mars Mission, 19: Crew Capsule, 20: Telescope, 21: Star, 22: Lunar Landing, 23: Space Station, 24: Jet/Plane, 25: Historic Mission(s), 26: Earth, 27: Habitat, 28: Astronaut/Cosmonaut, 29: Orbit, 30: Galaxy, 31: Future
September 28, 2025 at 5:02 AM
Reposted by astrafoxen
hbhammel.bsky.social
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
September 11, 2025 at 7:30 AM
Reposted by astrafoxen
timberwind.bsky.social
July 16, 2024 at 2:35 AM
astrafoxen.bsky.social
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
megschwamb.bsky.social Meg Schwamb @megschwamb.bsky.social · Sep 10
Silvia Protopapa talks about first JWST methane gas detection on dwarf planet Makemake. Third large KBO body with volatile release (Pluto and Triton - it's a captured dwarf planet orbiting Neptune are the other two). This is either an expanding coma or a bound atmosphere! Wow! #EPSCDPS2025
September 10, 2025 at 6:30 PM
Reposted by astrafoxen
spacewhalerider.com
Mimas science is serious business
September 9, 2025 at 2:29 PM
Reposted by astrafoxen
astrochara.bsky.social
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.
September 9, 2025 at 2:51 AM
astrafoxen.bsky.social
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)
Size and color comparison of the largest trans-Neptunian objects (TNOs) and dwarf planets of the Solar System. Newly named TNOs are highlighted in yellow. Starting from the top row, going from left to right: 1st row: Pluto & Charon, Eris & Dysnomia, Haumea & 2 moons, Makemake, Gonggong & Xiangliu 2nd row: Quaoar & Weywot, Orcus & Vanth, Sedna, Salacia, Mani, Aya 3rd row: Varda & Ilmare, Chiminigagua (formerly 2013 FY27), Achlys, Ixion 4th row: Varuna, Goibniu (formerly 2004 GV9), Ritona, Uni & Tinia (formerly 2002 UX25), Gǃkúnǁʼhòmdímà & Gǃòʼé ǃHú, Rumina (formerly 2005 RM43) 5th row: 2014 UZ224, 2010 JO179, 2005 QU182, Xewioso (formerly 2002 XW93). Saturn's moon Enceladus is shown for scale.
September 1, 2025 at 6:22 PM
astrafoxen.bsky.social
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... ☄️
August 29, 2025 at 12:07 AM
Reposted by astrafoxen
melina-iras07572.bsky.social
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...
Two sources with equal brightness
August 28, 2025 at 5:04 PM
Reposted by astrafoxen
melina-iras07572.bsky.social
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...
An image of two point-sources. The one on the left is brighter.
August 28, 2025 at 5:39 AM
astrafoxen.bsky.social
EEEEE LOOK AT IT :DDD
cosmos4u.bsky.social cosmos4u.bsky.social @cosmos4u.bsky.social · Aug 28
Whoa, the interstellar comet 3I/ATLAS clearly has a tail now! A raw image taken minutes ago with the GMOS instrument on Gemini South and shared live during the Shadow the Scientists event - I raised the contrast slightly.
August 28, 2025 at 3:02 AM
Reposted by astrafoxen
astrokiwi.bsky.social
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
VLT observations of interstellar comet 3I/ATLAS II. From quiescence to glow: Dramatic rise of Ni I emission and incipient CN outgassing at large heliocentric distances
We report VLT spectroscopy of the interstellar comet 3I/ATLAS (C/2025 N1) from $r_{\rm h}\!\simeq\!4.4$ to $2.85$ au using X-shooter (300-550 nm, $R\!\simeq\!3000$) and UVES (optical, $R\!\simeq\!35k-...
arxiv.org
August 27, 2025 at 1:38 AM
Reposted by astrafoxen
megschwamb.bsky.social
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...
NASA’s Webb Space Telescope Observes Interstellar Comet - NASA Science
NASA’s James Webb Space Telescope observed interstellar comet 3I/ATLAS Aug. 6, with its Near-Infrared Spectrograph instrument. The research team has been
science.nasa.gov
August 25, 2025 at 10:28 PM
astrafoxen.bsky.social
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"
NASA’s Webb Space Telescope Observes Interstellar Comet - NASA Science
NASA’s James Webb Space Telescope observed interstellar comet 3I/ATLAS Aug. 6, with its Near-Infrared Spectrograph instrument. The research team has been
science.nasa.gov
August 25, 2025 at 10:09 PM
Reposted by astrafoxen
hbhammel.bsky.social
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'.
The images shows two panels with spectroscopy of interstellar comet 3I/ATLAS. SPHEREx 0.75-5.0 μm 2-pixel radius aperture spectrophotometry (left) and solar spectrum corrected reflectance (right) for 3I. Red arrows denote possible significant background contamination due to known background sources. The arrows start at the measured flux+1σ. For the reflectance, the NASA-IRTF/SpeX 0.7-2.5 μm spectrum (green) is overlaid. The two sets of measurements are consistent, and characterized by a slightly rising slope from 0.7-1.0 μm, a flat regime from 1.0-1.5 μm, a shallow absorption at 1.5 and 2.1 μm, and a strong falloff starting at 2.4 μm. The SPHEREx spectrophotometry stays low from 2.5-5.0 μm, with a huge uptick at 4.3 μm due to CO2 gas emission. Also overlaid for comparison is the average “cliff” KBO spectrum of dePra+ 2025 (pink). The image shows three measurements of interstellar object 3I/ATLAS with SPHEREx at 3.0, 4.26, and 4.7 μm. showing H2O, CO2, and CO gas comae from left to right respectively. The object is undetected in H2O and CO, with 2-pixel radius preliminary conservative upper limits of 0.45 and 0.99 mJy. By contrast, a bright CO2 coma with central PSF flux = 33mJy that extends out to at least 30-pixel (=348,000 km) was found. This observed minimum size for the CO2 coma corresponds to ~700,000-second mean lifetime at vgas = 0.48 km/sec. The reported photodissociation lifetime for CO2 at 1au is 135hrs = 486,000 seconds (Huebner+1992), which scales by 1/r2 to ~4,670,000 seconds at 3.2au.
August 25, 2025 at 6:02 PM
Reposted by astrafoxen
melina-iras07572.bsky.social
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...
A bright point source in the center with a dim source on the right
August 18, 2025 at 8:04 AM
Reposted by astrafoxen
melina-iras07572.bsky.social
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...
August 23, 2025 at 12:34 PM
astrafoxen.bsky.social
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
August 23, 2025 at 1:59 AM
astrafoxen.bsky.social
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
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.
July 30, 2025 at 8:03 PM
astrafoxen.bsky.social
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)
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
July 22, 2025 at 3:30 AM