Updated 2025 March 21
On 2024 December 8, Roberto Haver reported (comets-ml) having detected a tail in images taken on December 2. Alan Hale confirmed the tail on December 21. A month later the MPC issued MPEC 2025 A-142 [2025 January 8] CBET 5489 gives more details of the original discovery and the 2024 re-discovery. It was at perihelion in 2024 December.
PanSTARRS 1 accidentally recovered 2019 Y3 on 2025 January 7.22 at 19th magnitude. It was briefly posted on the PCCP as P125u6N, then removed without people noticing. Further reports also made it to the PCCP as A11hRte (January 20), A11hVVH (January 21) and C44DR81 (February 3). Michael Jaeger also made an independent recovery on January 29.8 that was reported to the CBET. [MPEC 2025-C161, CBET 5504, 2025 February 11/12] The recovery indicates a correction of Delta(T) = +1.37 days to previous predictions. The comet reaches perihelion at 0.9 au in March. The comet will pass 0.34 au from the earth on 2025 March 18 and 0.33 au from Jupiter on 2033 July 4. The comet passed 0.072 au from Venus in 1958 and 0.11 au from Jupiter in 1926. It is an intrinsically faint object that is only predicted to reach 16th magnitude during the approach, which is favourable for northern hemisphere observers.
2019 A8 was accidentally recovered in images taken images taken with the 1.5-m reflector of the Mt Lemmon Survey on January 24.39 at 21st magnitude. Michael Jaeger et al also made an independent recovery on February 22. [MPEC 2025-D234, CBET 5516, 2025 February 27/28] The relatively short arc, combined with a close approach to Jupiter gave rise to a Delta(T) of +49.2 days for the time of perihelion compared to previous predictions. The comet made close approaches of 0.3 au to Jupiter in 2009 November and 2021 November. It now has a period of 6.3 years and is at perihelion at 2.1 au in 2025 March.
Sam Deen subsequently found pre-discovery images from PanSTARRS taken on 2014 July 4.58, with other images from NEOWISE on January 31 and the CFHT on July 18. The comet was designated 2014 N4 for the return. He then found images from Suburu taken on 2017 January 21.23, 23 and 26, and 2016 December 23 and the comet was designated 2017 B6 for this return. He also found images taken by the CFHT on 2004 August 19, but for some reason it was not given a designation at this return. [MPEC 2025-D238, 2025 February 28]. Further details are given in a CBET, including that the comet passed 0.011 au from Venus in 1997 July and 0.079 au from Venus in 2020 December. [CBET 5520, 2025 March 11]. The next close approach to Venus is not until 2060.
Sam Deen commented on the comets-ml that the magnitude was quite variable, but none of the images were clear enough to detect any cometary activity. The observations gave a deterministic orbital solution going back to around 1800 and forwards to around 2200, and a very chaotic and very quasi-hilda-esque orbital evolution all the while. It spent between 1796 and 1979 (nearly two centuries) with a perihelion further than Jupiter's semimajor axis in a 29P-type gateway comet orbit, and the solution confirms that in 2054 it will become a more 'classical' quasi-hilda. He also noted that there were suggestions of non-gravitational effects, confirming the cometary nature.
When observing a comet please try to forget how bright you think the comet should be, what it was when you last viewed it, what other observers think it is or what the ephemeris says it should be.
The order given here is provisional and based on the logical sequence of linked orbits. The final numbering scheme does not seem to follow this logical pattern.
Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk