3I/ATLAS is Green After Perihelion

It went through a color change and that appears natural.  this from Avi's newsletter.  we have had falsification on podcasts naming him.,,,,,,,,,.

so far it appears normal and we have see anti tails before

Keep watching.  At least we are seeing all this now.

3I/ATLAS is Green After Perihelion

Avi Loeb

An image of 3I/ATLAS, taken on November 26, 2025 by the Gemini Multi-Object Spectrograph (GMOS) on Gemini North on Maunakea in Hawaii, an observatory funded by the U.S. National Science Foundation (NSF) and operated by NSF’s NOIRLab. This image is composed of exposures taken through four filters — blue, green, orange, and red. The exposures were centered on 3I/ATLAS while the background stars appear as streaks. The teardrop shape of the green glowing halo around 3I/ATLAS features an anti-tail in the direction of the Sun, towards the lower left. (Image Credit: International Gemini Observatory/NOIRLab/NSF/AURA/B. Bolin)

Exactly four weeks after its perihelion, on November 26, 2025, the interstellar object 3I/ATLAS was imaged by the Gemini Multi-Object Spectrograph (GMOS) on the 8.1-meter telescope Gemini North at Maunakea, Hawaii, an observatory funded by the U.S. National Science Foundation (NSF) and operated by NOIRLab. The post-perihelion image, posted here, combines exposures through four filters — blue, green, orange, and red, and its peak brightness is centered on the nucleus 3I/ATLAS. The color of the glowing halo appears green, possibly as a result of diatomic carbon (C2) molecules which emit green light.

A pre-perihelion image, posted here on September 4, 2025, from the twin 8.1-meter telescope Gemini South in Chile, displayed a red color of the glow around 3I/ATLAS. The change in colors from red to green means that the molecular composition of the plume of gas shed by 3I/ATLAS had changed near the Sun.

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ESA’s X-ray space observatory XMM-Newton observed 3I/ATLAS with its European Photon Imaging Camera (EPIC) for 20 hours on December 3, 2025 from a distance of about 284 (+/-2) million kilometers (as reported here). Similarly to the report from JAXA’s XRISM image earlier this week (discussed here), the X-ray glow in this image results from the interaction of the solar wind with the plume of gas surrounding 3I/ATLAS which was known to exist for five months.

Press enter or click to view image in full size

X-ray image of 3I/ATLAS, taken by ESA’s XMM-Newton spacecraft. (Credit: ESA/XMM-Newton/C. Lisse, S. Cabot & the XMM ISO Team)

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Is 3I/ATLAS Related to the longest-duration gamma-ray burst GRB 250702b?

Before my routine jog at sunrise, I was asked about an unusual coincidence reported on video here, between the arrival direction of 3I/ATLAS when it was discovered on July 1, 2025 (RA=272 degrees and Dec= -19 degrees) and the arrival direction of the longest ever (lasting 25,000 seconds or about 7 hours) gamma-ray burst GRB 250702b — which was discovered on July 2, 2025 (RA=285 degrees and Dec=-8 degrees) and reported here. The angular separation between the two directions was 17 degrees on July 2, 2025, corresponding to a chance alignment probability of 0.02. However, the date of July 2, 2025 is not particularly significant since we just happened to discover 3I/ATLAS around that time but 3I/ATLAS was moving through the Oort Cloud of the Solar system for 8,000 years before that. Since there are several hundred gamma-ray bursts per year spread evenly across the entire sky, a chance coincidence of 0.02 between one of them and 3I/ATLAS is not unusual. Such a coincidence is expected to occur many times over a period as long as 8,000 years even if the ultra-long duration of GRB 250702b appears only in a small fraction of the burst population. In fact, we know of another gamma-ray burst that lasted about 4–7 hours on December 9, 2011, GRB 111209A, as reported here. This burst was followed by a supernova, as reported here, and is definitely the result of an exploding star at a luminosity distance of 13.7 billion light years. This means that an ultra-long duration burst occurs as a result of a random cosmic event once per 14 years, during which there is a total of about 4,000 bursts. A 7-hour gamma-ray burst should therefore coincide to within 17 degrees of the arrival direction of 3I/ATLAS once per 670 years. Altogether, there had been a dozen such coincidences while 3I/ATLAS was traveling inside the Solar system over the past 8,000 years and the latest one happened to occur this year. But even during 2025 alone, there had been about 6 gamma-ray bursts of normal duration that coincided to within 17 degrees of the arrival direction of 3I/ATLAS.