The interstellar object 3I/ATLAS has a structure of three jets that exhibit periodic oscillations, according to a recent analysis based on images of Telescópio Espacial Hubble captured between November 30 and December 27, 2025, after the object’s perihelion. The most prominent jet, directed in the opposite direction to Sol, demonstrates a wobble with a period of 7.20 hours, with an angular variation of approximately 20 degrees. The total brightness variability follows this movement, recording a period of 7.136 hours and an amplitude of around 30%. Astrônomos interpret these patterns as precession or nutation of the nucleus’s attitude, resulting from misalignment between the axis of rotation and the nucleus’s axes of symmetry.
The axis of rotation maintains an alignment close to the solar direction, within 20 degrees, which contributes to the stability observed in the jets. Apenas About 1% of the object’s total brightness comes from the reflection of sunlight by the core, estimated to be 2.6 kilometers in diameter. Most of the luminosity derives from cometary activity in jets of gas and dust.
Three jet configuration
The jets exhibit distinct position angles (PA) with specific oscillation amplitudes. Jet 1 has a PA of 55 degrees with an amplitude of 12.8 degrees. Jet 2, oriented in the solar direction, registers a PA of 290 degrees with an amplitude of 20 degrees. Jet 3 shows a PA of 170 degrees with an amplitude of 12.6 degrees.
The anti-solar jet at PA 290 degrees concentrates the most evident wobble, with a cycle of 7.2 hours. Essas measurements derive from image processing that reveals the symmetry and morphological evolution of the jets.
The variations in the jets alternate between collimated and fan shapes throughout each oscillation cycle. Essa transition explains the non-sinusoidal variability in total brightness.
Interpretation of precession
The characteristic periodicity of about 7.1 hours is related to the rotation of the nucleus out of alignment with its main axes of symmetry. The movement of precession and nutation generates quasi-periodic wobbles in the jets. Essa dynamics affect the amplitudes and phases of the oscillations as the morphology of the jets evolves.
Aligning the rotation axis with the solar direction facilitates the formation of stable structures, such as the extended anti-tail jet. Complementary Observações indicate that multiple jets contribute to balancing the object’s rotation.
Details of post-perihelion observations
Processed Hubble images highlight the morphological transition in the jets. Brightness variability tracks changes between narrow and scattered jets. Esses patterns occur in synchrony with the measured angular oscillations.
The analysis reinforces that the phenomenon results from natural physical processes in the rotating core. The estimated core diameter supports the predominance of jet emission over surface reflection.
Core rotational dynamics
The misalignment between rotation axis and core symmetry produces observable quasi-periodic variability. The jets act as sensitive indicators of this misalignment, exhibiting consistent angular excursions. The sensitivity to collimation of the jets explains variations in the light curve.
Previous research has detected similar modulations in pre-perihelion phases, with periods close together. The current post-perihelion configuration confirms the persistence of these behaviors.
Symmetrical structure observed
The three-jet system maintains approximately 120 degrees separation in the sky. Essa geometry appears in processing filters that remove the symmetrical glow of the coma. The anti-solar jet supplements the structure with a greater extension in the solar direction.
The oscillations occur in a coordinated manner, suggesting dynamic interaction between the jets. The dominant period of 7.1 hours unifies the observed variations.
The interstellar object 3I/ATLAS continues to exhibit unique features in its cometary activity as it moves away from Sol.