Detection of a Low-Brightness Tail in A/2025 Y1

ATel #17593; M. Serra-Ricart (Light Bridges, IAC, ULL), J. Licandro (IAC, ULL), M. R. Alarcon (Light Bridges, IAC, ULL)
on 12 Jan 2026; 21:39 UT
Distributed as an Instant Email Notice Comets
Credential Certification: Miquel Serra-Ricart (mserra@iac.es)

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Asteroidal object A/2025 Y1 has been extensively monitored since its discovery on 2025 December 12 using the imaging capabilities of the Two-Meter Twin Telescope (TTT) at the Observatorio del Teide (IAC, Tenerife, Spain). We report the detection of a faint tail associated with A/2025 Y1. Deep optical images obtained on 2026 January 11 using TTT3 show a low-surface-brightness tail visible in the stacked data (see attached figure). Standard reduction procedures (bias subtraction, flat-fielding, and stacking) were applied. The tail extends up to 4 arcsec from the optocenter (red cross in the attached image) and has a measured position angle of PA = 291d +/- 1d, consistent with the projected antisolar direction (PsAng = 292d). The morphology and orientation of the feature are consistent with a weak dust tail produced by low-level activity. Further observations are encouraged to confirm the persistence and evolution of this feature. TTT3 is a 2 m f/6 Ritchey-Chretien telescope currently in its commissioning phase. Images from TTT3 were acquired using COLORS, a 2k x 2k camera mounted at the Nasmyth-2 focus and equipped with a back-illuminated BEX2-DD CCD, yielding a field of view of 7.85 x 7.85 arcmin and a plate scale of 0.23 arcsec per pixel. TTT is operated by Light Bridges in Tenerife, Canary Islands (Spain). The observation time rights (DTO) used for this research were consumed in the PEI “PERHELIO26”. This research used storage and computing capacity in ASTRO POCs EDGE computing center at Tenerife under the form of Indefeasible Computer Rights (ICR). Figure 1. Stacked image of A/2025 Y1 obtained on 2026 January 11. The antisolar direction is indicated by the yellow arrow, and the projected velocity vector is shown by the red arrow. North is up, east is to the left. The blue line represents the position angle (PA) of the tail.

TTT3 image with detected faint tail