# perihelion
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ufofeed.bsky.social
Perihelion Asymmetry In The Water Production Rate Of Tthe Interstellar Object 3I/ATLAS

https://www.ufofeed.com/201246/perihelion-asymmetry-in-the-water-production-rate-of-tthe-interstellar-object-3i-atlas/

Representative SWAN full-sky Lyman-α map (2025 Nov 13), showing the simultaneous …
Perihelion Asymmetry In The Water Production Rate Of Tthe Interstellar Object 3I/ATLAS - UFO FEED
3I/ATLAS is an interstellar object whose activity provides critical insights into its composition and origin. However, due to its orbital geometry, the object
www.ufofeed.com
January 27, 2026 at 4:57 AM
paper.bsky.social
[10/30] 216 Likes, 56 Comments, 2 Posts
2601.16983, astro-ph․EP, 23 Jan 2026

🆕Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS

Willem B. Hoogendam, David O. Jones, Bin Yang, Benjamin J. Shappee, James J. Wray, Karen J. Meech, Christopher Ashall, Dhvanil D. Desai,...
The environs of other stellar systems may be directly probed by analyzing the cometary activity of interstellar objects. The recently discovered interstellar object 3I/ATLAS was the subject of an intensive worldwide follow-up campaign in its pre-perihelion approach. Now, 3I/ATLAS has begun its post-perihelion departure from the Solar System. In this letter, we report the first post-perihelion blue-sensitive integral-field unit spectroscopy of 3I/ATLAS using the Keck Cosmic Web Imager on November 16, 2025. We confirm previously reported CN, Fe, and Ni outgassing along with detections of carbon chain molecules $\mathrm{C}_2$ and $\mathrm{C}_3$. We calculate production rates for each species. We find Fe and Ni production rates of $\mathrm{Q_{Fe}} = (9.55\pm3.96)\times10^{25}$ atoms s$^{-1}$, and $\mathrm{Q_{Ni}} = (6.61\pm2.74)\times10^{25}$ atoms s$^{-1}$, resulting in a ratio of $\log(\mathrm{Q_{Ni}} / \mathrm{Q_{Fe}}) = -0.16\pm0.03$, which matches Solar System comets well and continues the pre-perihelion trend of declining $\log(\mathrm{Q_{Ni}} / \mathrm{Q_{Fe}})$ with $r_h$. We investigate the radial distributions of these elemental species and find characteristic $e$-folding radii of 3880$\pm$39 km for Ni, 6053$\pm$68 km for CN, 4194$\pm$45 km for $\mathrm{C}_2$, and 3833$\pm$45 km for $\mathrm{C}_3$. Compared to pre-perihelion measurements, these radii have increased by a factor of $\sim$6.5--7. Our post-perihelion observations reveal that 3I/ATLAS continues to exhibit cometary behavior broadly consistent with Solar System comets.
January 27, 2026 at 12:07 AM
astrobiology.bsky.social
Perihelion Asymmetry In The Water Production Rate Of Tthe Interstellar Object 3I/ATLAS
astrobiology.com/2026/01/peri... #astrobiology #astrochemistry #3IATLAS #interstellar
Perihelion Asymmetry In The Water Production Rate Of Tthe Interstellar Object 3I/ATLAS - Astrobiology
3I/ATLAS is an interstellar object whose activity provides critical insights into its composition and origin
astrobiology.com
January 26, 2026 at 6:19 PM
michael-w-busch.bsky.social
Today on the #arXiv:

Hoogendam et al. 2026, "Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS" - arxiv.org/abs/2601.16983

#3I/ATLAS continues to be a typical comet apart from where it came from. Including the near-solar amounts of iron and nickel.
Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS
The environs of other stellar systems may be directly probed by analyzing the cometary activity of interstellar objects. The recently discovered interstellar object 3I/ATLAS was the subject of an inte...
arxiv.org
January 26, 2026 at 4:40 PM
rollforfocus.bsky.social
ADHD Burst: Perihelion is now available!
Warnings: explicit language, complicated relationship dynamics

Listen at: shows.acast.com/rollforfocus... or anywhere you listen to podcasts!
ADHD Burst: Perihelion | Roll For Focus
shows.acast.com
January 26, 2026 at 1:20 PM
trendlyric.bsky.social
Comet ATLAS Reveals Massive Organic Release Post-Perihelion

Quick Summary Comet C/2023 A3 (ATLAS) has dramatically changed its activity after its closest approach to the Sun (perihelion), exhibiting a massive release of organic molecules. This unexpected behavior challenges conventional…
Comet ATLAS Reveals Massive Organic Release Post-Perihelion
Quick Summary Comet C/2023 A3 (ATLAS) has dramatically changed its activity after its closest approach to the Sun (perihelion), exhibiting a massive release of organic molecules. This unexpected behavior challenges conventional understanding of cometary evolution. What Happened Following its perihelion passage, Comet ATLAS surprised astronomers by transitioning from a relatively quiet state to an exceptionally active one. Observations confirmed it ejected a vast amount of complex organic compounds, a significant departure from typical cometary outbursts.
www.trendlyric.com
January 26, 2026 at 12:46 PM
astroarxiv.bsky.social
Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS. Willem B. Hoogendam et. al. https://arxiv.org/abs/2601.16983
Figure 1 Figure 2 Figure 3 Figure 4
January 26, 2026 at 9:44 AM
astrophep-bot.bsky.social
Hoogendam, Jones, Yang, Shappee, Wray, Meech, Ashall, Desai, Hinkle, Hoffman, Medler, Pfeffer, Zhao: Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS https://arxiv.org/abs/2601.16983 https://arxiv.org/pdf/2601.16983 https://arxiv.org/html/2601.16983
January 26, 2026 at 6:41 AM
krxiv-astro-ph.bsky.social
Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS
https://arxiv.org/pdf/2601.16983
Willem B. Hoogendam et al.
https://arxiv.org/abs/2601.16983
arXiv abstract link
arxiv.org
January 26, 2026 at 4:31 AM
exocourier.bsky.social
[2601.16983] Willem B. Hoogendam et al.: Post-Perihelion Integral Field Spectroscopy of the Interstellar Comet 3I/ATLAS. link
January 26, 2026 at 3:04 AM
bethanylaurel.bsky.social
Nah, Perihelion from the Murderbot Diaries.
January 25, 2026 at 10:26 PM
therlkorbel.bsky.social
Perihelion from Halo? More like a toilet paper role?
January 25, 2026 at 8:46 PM
zzzyzzyva.bsky.social
4. Kepler used the Harmonic Law to connect the, then, known planetary motions into a grand "cosmic symphony," where the angular velocities of planets at their fastest (perihelion) and slowest (aphelion) points corresponded to musical intervals. www.youtube.com/watch?v=zwZz...
January 25, 2026 at 8:23 PM
3i-atlas.bsky.social
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased

https://www.ufofeed.com/200353/spherex-re-observation-of-interstellar-object-3i-atlas-in-december-2025-detection-of-increased-post-perihelion-activity-refractory-coma-dust-and-new-coma-gas-species/

…
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species - UFO FEED
In December-2025, the NASA SPHEREx spacecraft re-observed ISO 3I/ATLAS post-perihelion, finding a much more active object compared to August-2025 SPHEREx
www.ufofeed.com
January 25, 2026 at 11:00 AM
3i-atlas.bsky.social
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased

https://www.ufofeed.com/200353/spherex-re-observation-of-interstellar-object-3i-atlas-in-december-2025-detection-of-increased-post-perihelion-activity-refractory-coma-dust-and-new-coma-gas-species/

…
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species - UFO FEED
In December-2025, the NASA SPHEREx spacecraft re-observed ISO 3I/ATLAS post-perihelion, finding a much more active object compared to August-2025 SPHEREx
www.ufofeed.com
January 25, 2026 at 11:00 AM
ufofeed.bsky.social
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased

https://www.ufofeed.com/200353/spherex-re-observation-of-interstellar-object-3i-atlas-in-december-2025-detection-of-increased-post-perihelion-activity-refractory-coma-dust-and-new-coma-gas-species/

…
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species - UFO FEED
In December-2025, the NASA SPHEREx spacecraft re-observed ISO 3I/ATLAS post-perihelion, finding a much more active object compared to August-2025 SPHEREx
www.ufofeed.com
January 25, 2026 at 10:57 AM
bethanylaurel.bsky.social
Perihelion, because it is an asshole.
therlkorbel.bsky.social R. L. Korbel @therlkorbel.bsky.social · 2d
Sci-fi ships pile mass around reactors for radiation shielding, but that's heavy and costly for interstellar hauls. Avatar's ISV nails it. A long spindle separates the crew from the engines. Distance as a free shield.

What is your fave sci-fi ship and why? #SFF #scifi #worldbuilding
January 25, 2026 at 3:40 AM
ca-nb.bsky.social
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species

https://www.newsbeep.com/ca/431092/

(Top Insets) SPHEREx 0.75-5.0μm imaging of 3I/ATLAS taken on 08-to-15-Dec2025. The …
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species - Canada News Beep
In December-2025, the NASA SPHEREx spacecraft re-observed ISO 3I/ATLAS post-perihelion, finding a much more active object compared to August-2025 SPHEREx
www.newsbeep.com
January 24, 2026 at 10:40 PM
astroarxiv.bsky.social
Perihelion Asymmetry in the Water Production Rate of the Interstellar Object 3I/ATLAS. Hanjie Tan (1) et. al. https://arxiv.org/abs/2601.15443
Figure 1 Figure 2 Figure 3 Figure 4
January 24, 2026 at 10:03 PM
ie-news.bsky.social
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species

https://www.europesays.com/ie/301903/

(Top Insets) SPHEREx 0.75-5.0μm imaging of 3I/ATLAS taken on 08-to-15-Dec2025. The …
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species - Ireland
In December-2025, the NASA SPHEREx spacecraft re-observed ISO 3I/ATLAS post-perihelion, finding a much more active object compared to August-2025 SPHEREx
www.europesays.com
January 24, 2026 at 9:15 PM
nz-nb.bsky.social
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species

https://www.newsbeep.com/nz/250029/

(Top Insets) SPHEREx 0.75-5.0μm imaging of 3I/ATLAS taken on 08-to-15-Dec2025. The …
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species - New Zealand News Beep
In December-2025, the NASA SPHEREx spacecraft re-observed ISO 3I/ATLAS post-perihelion, finding a much more active object compared to August-2025 SPHEREx
www.newsbeep.com
January 24, 2026 at 8:30 PM
pisiku.bsky.social
Max Richter - Perihelion

youtube.com/watch?v=7tTC...
Richter: Perihelion
YouTube video by Max Richter - Topic
youtube.com
January 24, 2026 at 8:13 PM
techdna.bsky.social
SPHEREx Reobservation of Interstellar Object 3I/ATLAS in December 2025: Increased Post-Perihelion Activity, Flame-Retardant Coma Dust, and Detection of New Coma Gas

(Top inset) SPHEREx 0.75-5.0μm imaging of 3I/ATLAS taken from December 8th to 15th, 2025. The 6.3 ft x 6.3 ft cutout contours are 5,…
SPHEREx Reobservation of Interstellar Object 3I/ATLAS in December 2025: Increased Post-Perihelion Activity, Flame-Retardant Coma Dust, and Detection of New Coma Gas
(Top inset) SPHEREx 0.75-5.0μm imaging of 3I/ATLAS taken from December 8th to 15th, 2025. The 6.3 ft x 6.3 ft cutout contours are 5, 20, and 50 times the background noise. Color bars are displayed in MJy/sr. The celestial north and east directions (black arrows) are shown, along with the antivelocity (dashed blue) and antisun (solid red) directions. In December 2025, the NASA SPHEREx spacecraft reobserved ISO 3I/ATLAS after perihelion and found a much more active object compared to the SPHEREx preperihelion observation in August 2025, and significant evidence of development into a cometary body that had completely sublimated all ice.
yojanasewa.com
January 24, 2026 at 7:39 PM
astrobiology.bsky.social
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species
astrobiology.com/2026/01/sphe... #astrobiology #astronomy #interstellar #3IATLAS
SPHEREx Re-Observation of Interstellar Object 3I/ATLAS in December 2025: Detection of Increased Post-Perihelion Activity, Refractory Coma Dust, and New Coma Gas Species - Astrobiology
he NASA SPHEREx spacecraft re-observed ISO 3I/ATLAS post-perihelion
astrobiology.com
January 24, 2026 at 7:12 PM
drnereide.bsky.social
After perihelion, the trajectory became hyperbolic, and the comet may be ejected from the Solar System, reaching 200 AU from the Sun by the year 2237.

Further reading

➡️ www.nasa.gov/blogs/watch-...

➡️ science.nasa.gov/earth/earth-...

4/4
Ancient Oort Cloud Comet to Make First Documented Pass By Earth in Mid-October - NASA
An ancient celestial traveler will make its first close pass by Earth in mid-October. Mark those calendars – because it might not be back. The Oort Cloud comet, called C/2023 A3 Tsuchinshan-ATLAS, was...
www.nasa.gov
January 24, 2026 at 3:54 PM