A recent study using the Hubble Space Telescope has provided new insights into comet 3I/ATLAS. The data reveals a diffuse glow ahead of the comet’s motion towards the Sun, defying the expected trail of gas and dust typical of comets.
Two research papers published online recently shed light on the object’s properties. The first paper analyzed the spectrum of 3I/ATLAS taken by the SOAR Telescope in Chile during its closest approach to the Sun. The results show no discernible gas emission from common comet molecules, raising questions about the underlying mechanisms driving its early onset coma.
The second study focuses on images captured by the Hubble Space Telescope on July 4-5, 2025. Contrary to expectations, these images reveal a comet with a small nucleus surrounded by a vast dust cloud, rather than the expected tail of gas and dust. The researchers propose that a forward glow could be explained if the nucleus does not spin rapidly.
According to data from ground-based telescopes, 3I/ATLAS has a rotation period of approximately 16 hours and 8 minutes. During this time, the dayside surface cools faster than expected, causing the evaporated dust to cross significant distances – up to 10,000 kilometers in just half of its rotation period.
The mystery surrounding 3I/ATLAS’s behavior raises further questions about the comet’s nature and potential explanations for its unusual glow. Upcoming data from the Webb telescope may help unravel the object’s details, shedding light on the underlying mechanisms driving its anomalous emission.
Source: https://avi-loeb.medium.com/hubble-space-telescope-shows-a-diffuse-glow-ahead-of-3i-atlas-b32e6075d7ac