jet detection on interstellar comet 3I/ATLAS with the Two-meter Twin Telescope
ATel #17445; M. Serra-Ricart (Light Bridges, IAC, ULL), J. Licandro (IAC, ULL), M. R. Alarcon (IAC, ULL)
on 15 Oct 2025; 19:45 UT
Distributed as an Instant Email Notice Comets
Credential Certification: Miquel Serra-Ricart (mserra@iac.es)
We report a faint jet detected in deep g-band images of the interstellar comet 3I/ATLAS, also known as C/2025 N1 (ATLAS), obtained with the Two-meter Twin Telescope at Teide Observatory during the night of 2 August 2025 (UT). Between 21:18 and 00:16 UT, a total of 159 individual exposures of 50s each in the g band were acquired and co-added following the apparent motion of the object and centered on the comet optocenter.
A Laplace-filtered image of the central coma of 3I/ATLAS, obtained following the method described by Serra-Ricart & Licandro (2015, ApJ, 814, 49), shows a faint jet at a position angle (PA) of 286.9+- 0.9 degrees (purple line), coincident with the broad, sunward-directed plume detected in visible images along PA = 280 +- 10 degrees (ATel #17350).
The PA of the detected jet was measured at a projected distance of 6000 km from the comet optocenter (indicated by the red lines). The projected velocity vector of the comet (blue arrow) and the antisolar direction (yellow arrow) are also shown, together with the image orientation and a distance scale.
jet image of 3I/ATLAS
https://drive.google.com/file/d/1PpZNdfsWIiMvkGME8dCr810xu47ClDQd/view?usp=sharing
jet image of 3I/ATLAS
