Images of 3I/Atlas have been released from ESA's ExoMars Trace Gas Orbiter captured between the 1st and 7th October , an attempt to image the object by ESA's Mars Express seems not to have captured much but scientists are still examining the data .... we await with anticipation the results from NASA's Mars Reconnaissance Orbiter which are delayed due to the US government shutdown... hopefully this doesn't affect the plan to send out Juno to take a parting look at the curious object.
![[Image: ExoMars_Trace_Gas_Orbiter_observes_comet...rticle.gif]](https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2025/10/exomars_trace_gas_orbiter_observes_comet_3i_atlas_gif/26909471-1-eng-GB/ExoMars_Trace_Gas_Orbiter_observes_comet_3I_ATLAS_GIF_article.gif)
Quote:CaSSIS could not distinguish the nucleus from the coma, because 3I/ATLAS was too far away. Imaging this kilometre-wide nucleus would have been as impossible as seeing a mobile phone on the Moon from Earth.
But the coma, measuring a few thousand kilometres across, is clearly visible. The coma is created as 3I/ATLAS approaches the Sun. The Sun’s heat and radiation is bringing the comet to life, causing it to release gas and dust, which collects as this halo surrounding the nucleus.
The full size of the coma could not be measured by CaSSIS because the brightness of the dust decreases quickly with distance from the nucleus. This means that the coma fades into the noise in the image.
Typically, material from the coma is swept into a long tail, which can grow up to millions of kilometres long as the comet moves closer to the Sun. The tail is much dimmer than the coma. We can’t see the tail in the CaSSIS images, but it may become more visible in future observations as the comet continues to heat up and release more ice.
https://www.esa.int/Science_Exploration/...t_3I_ATLAS