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An astronomer from the USA captured several images of the interstellar comet 3I/ATLAS in the early morning hours. It was not visible to us before.
3I/ATLAS before disappearing behind the sun
(Image: International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist; Image Processing: J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab))
The interstellar comet 3I/ATLAS has reappeared from behind the sun and can once again be observed from Earth. This was announced by astronomer Qicheng Zhang from the Lowell Observatory in the USA on his microblogging page. He has since published two images of the celestial body, which he took over the weekend.
Under ideal conditions, 3I/ATLAS should therefore be visible in the early morning, though so far only as a diffuse small spot. It won't look particularly impressive, Zhang explained to the science magazine Livescience, but at least all that's needed now is a clear sky and a very low horizon in the east.
3I/ATLAS was discovered in early July by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile, hence its name. The interstellar comet is actually only the third visitor in our solar system discovered during its passage. In recent weeks, from Earth's perspective, it was behind the sun on its trajectory through the solar system; its closest approach to our star had to be observed by probes operating throughout the solar system. This was particularly important because during this approach, it loses a significant amount of material, which provides insights into its composition.
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Before Zhang's images clearly showed that 3I/ATLAS is again visible from Earth, he pointed out a peculiarity in a still-unreviewed research paper. Observations with various measuring devices have shown that the comet brightened much faster during its approach to the sun than is known for comets from the Oort Cloud at the edge of the solar system. He and his colleague Karl Battams have no explanation for this, and only further observations can help. Therefore, it is not yet possible to accurately predict how the object will behave in the future. The brightness is due to gas and dust being pushed out of the comet by the sun, which reflect light.
(mho)
