BAA Comet Section : Comets discovered in 2025
Updated 2025 April 29
1743 X1
Maik Meyer and Gary Kronk have derived a new orbit
for 1743 X1 and linked it to 1402 D1 and possibly earlier comets. They predict it will return around 2097. Tail simulation broadly agrees with the
main linkage, but raises some queries as to previous apparitions. Certainty will only come when the comet is recovered.
2007 SA24 (P/Lemmon)
David Rankin discovered a 20th magnitude comet in images taken with the
1.5-m reflector of the Mt Lemmon Survey on .2023 October 10.38. It was quickly
identified with an object of 21st magnitude discovered on 2007 September 25.28 in images
also taken with
the 1.5-m reflector of the Mt Lemmon Survey. It was observed until 2008 February by several observatories.
It seems to have been forgotten about by the MPC and the 2023 recovery was not
given a designation. [MPEC 2025-H103, CBET 5548, 2025 April 24/29]. The comet
was at perihelion at 2.7 au in 2022 December and has a period of 15.5 years.
2009 KF37 [P/Palomar]
There are a few inconsistencies in the MPEC announcing this object. It gives the discovery observation by the PTF as being on 2009
May 27.20. Cometary activity was first detected in an image from 2009 May 25 (which are given in the CBET),
but not reported until 2012 October 16. Pre-discovery LONEOS observations from 2001 were then found. The comet is next
at perihelion at 2.8 au in 2026 January and has a period of 8.3 years. [MPEC 2025-H87, CBET 5543, 2025 April 23/26].
The comet passed 0.95 au from Jupiter in 2012 January.
2010 KG43 [P/WISE-LINEAR]
The WISE spacecraft observed an object on 2010 May 20.54 and followed it until May 21.66. Other observatories followed it during 2010, though
only one reported cometary activity and then in 2012. It was independently found by LINEAR on 2010 August 3.41 and designated as 2010 PT8.
In 2023 Sam Deen found further indications of cometary activity at 2010 return,
which encouraged other observers to check at the next return in 2023. The comet has a period of 13.2 years with perihelion
at 2.9 au in 2023 August. [MPEC 2025-H90, CBET 5545, 2025 April 22/26]
2010 LH155 [P/WISE]
Y. Ramanjooloo found a comet in PanSTARRS imagery on 2024 December 31.60. It was posted on the PCCP as P124Qvg. PanSTARRS then
found pre-discovery images from 2024 November. This was then linked to an object that was observed at Cerro Paranal
in 2018 May and also observed by PanSTARRS. This was then further linked to an object observed by
the WISE spacecraft on 2010 June 14.71 and followed it until June 15.83. The CBET notes that it should have received provisional
designations at both the 2018 and 2024 returns.
The comet has a period of 7.2 years with perihelion
at 2.2 au. The comet passed 0.80 au from Jupiter on 1998 February 19 and 0.96 au on 2023 March 20 .
[MPEC 2025-H69, CBET 5540, 2025 April 22/24]
2012 KA51 [P/Palomar]
This object was discovered on 2012 May 22.16 by the Palomar Transient Factory (PTF) and observed for only a week without being recovered. Sam Deen found many more
unmeasured observations from PANSTARRS which showed it to be in a highly eccentric object with a perihelion of 4.896 au and an aphelion of 959 au.
in all of these observations it appears noticeably elongated (or too faint to make out features anyway). Furthermore, investigating the original PTF
images shows it as rather noticeably fuzzy. This was posted by Sam Deen on the comets-ml in 2021 April 7. It was finally recognised as a comet
by the MPEC in 2025 [MPEC 2025-H88, CBET 5549, 2025 April 23/30]. The comet was at perihelion at 4.9 au in 2011 November.
2017 FL36 (P/PANSTARRS)
Peter VanWylen suggested that 2017 FL36 might be a comet on the comets-ml. This was confirmed with the issue of MPEC 2025-H86 on 2025 April 23.
The comet was discovered by PanSTARRS on 2017 March 18.39 with observers reporting cometary features from 2017 March in 2024 February and May.
The comet is at perihelion at 2.8 au in 2025 August and has a period of 5.0 years. [MPEC 2025-H86, CBET 5551, 2025 April 23/ May 1]
2025 A1 [A/Lemmon]
An object of 21st magnitude was discovered on January 2.28 in images taken with
the 1.5-m reflector of the Mt Lemmon Survey. It was placed on the PCCP as CCMJ452.
There were pre-discovery images from Mt Lemmon (2024 October 28, November 14),
PanSTARRS (November 2, 27) and Kitt Peak-Bok (December 20).
[MPEC 2025-A108, 2025 January 6]. No cometary activity has been detected to date.
The object is at perihelion at 5.4 au in 2027 March.
2025 A2 (P/PANSTARRS)
PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
January 7.42. It was placed on the PCCP as P125uch. There were pre-discovery images from DECam on
2024 November 27, 28 and 30, Mt Lemmon on December 1 and 27 and PanSTARRS on December 23, 27, 31 and
2025 January 2.
[MPEC 2025-A162, CBET 5494, 2025 January 11] The comet was at perihelion at 3.4 au in 2024 October and has
a period of around 11 years. The comet passed 0.3 au from Jupiter in 2022
October.
2025 A3 (Tsuchinshan)
Zhijian Xu reported the discovery of a comet in survey images taken on January 5.82
using the 1.04-m f/1.8 Schmidt telescope at the
Xuyi Observatory of Purple Mountain Observatory (Tsuchinshan) in the course of
the "China Near Earth Object Survey Telescope" (CNEOST) search program. The
object was initially submitted as an asteroidal target by the CNEOST automated
system but was then found to show cometary feature. Zhijian then contacted the
Kottomia Observatory in Egypt for confirmatory observations. The comet was posted on
the PCCP as X85042 and PanSTARRS found pre-discovery observations from December 25, 28, 29
and January 4. [MPEC 2025-A178, CBET 5495, 2025 January 15]. The comet is at perihelion at 5.6 au
in 2026 January and has a period of about 33 years.
2025 A4 (PANSTARRS)
PanSTARRS 2 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
January 3.63. It was placed on the PCCP as P2225WF. There were pre-discovery images from Mt Lemmon on December 21.
[MPEC 2025-B11, CBET 5496, 2025 January 18] The comet was near perihelion at 3.8 au and has
a period of around 35 years, with an uncertainty of about a year.
2025 A5 (P/Catalina)
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.
2025 A6 (Lemmon)
An object of 22nd magnitude was discovered on January 3.34 in images taken with
the 1.5-m reflector of the Mt Lemmon Survey. It was placed on the PCCP as CCNG6P2.
There were pre-discovery images from PanSTARRS on November 12, 28, December 2, 6, 22, 23, 30.
[MPEC 2025-D55, CBET 5508, 2025 February 21/22].
The comet is at perihelion at 0.5 au in 2025 November and has a period of over 1000 years.
The comet could reach 10th magnitude in late
October, or possibly brighter if the initial magnitudes correspond to a nuclear magnitude.
During October it rapidly switches from a morning object at the start of the month, to an early evening
one at the end.
2025 A7 [A/Lemmon]
An object of 20th magnitude was discovered on January 6.49 in images taken with
the 1.5-m reflector of the Mt Lemmon Survey. It was placed on the PCCP as CCPHVR2.
There were pre-discovery images from PanSTARRS on 2024 December 2.
[MPEC 2025-D151, 2025 February 24]. No cometary activity has been detected to date.
The object is at perihelion at 2.9 au in 2025 March.
2025 B1 (PANSTARRS)
PanSTARRS 2 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
January 20.24. It was placed on the PCCP as P225G7o. There were pre-discovery images from Mt Lemmon on December 24 and January 3.
[MPEC 2025-B77, CBET 5497, 2025 January 23] The comet is at perihelion at 3.5 au in 2025 June.
2025 B2 (Borisov)
Gennady Borisov discovered a 20th magnitude comet in images taken with the MARGO 0.5-m f/1.9
reflector at Nauchnij, Crimea on January 20.78. It was placed on the PCCP as
gb00784 and quickly confirmed by other astrometrists. There was a pre-discovery image by PanSTARRS on January 8.29.
[MPEC 2025-C153, CBET 5501, 2025 February 9/10] The comet is at perihelion at 8.2 au in 2026 September.
The discovery is eligible for the Edgar Wilson Award.
2025 B3 (P/PANSTARRS)
2019 A8 was accidentally recovered in 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.
2025 C1 (P/ATLAS)
The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered an 18th magnitude object
in images taken with the 0.5 m Schmidt at Haleakala on February 2.63. It was posted on the NEOCP as A11izBV. Alan Hale
suggested that it showed some cometary nature on the comets-ml and this was soon confirmed. It was then transferred to
the PCCP until the orbit was published. [MPEC 2025-C158, CBET 5502, 2025 February 10]. It seems likely that the comet
was discovered in outburst as it brightened by a magnitude 24 hours after discovery
and there were no prediscovery observations. The comet was near perihelion at 2.7 au
and has a period of around 8.5 years, though this is uncertain by about 17 days.
The orbit has a Jupiter MOID of 0.25 au.
2025 D1 (Groeller)
Hannes Groeller discovered a comet of 20th magnitude on February 20.33 in images taken with
the 2.25-m Bok reflector at Kitt Peak. It was placed on the PCCP as C11KVH5.
Sam Deen soon found pre-discovery images from Kitt Peak (2018 June 6, 7, 9, 18, 2019 February 9, 12), CFHT (2022 February 2)
and Suburu (2022 May 30) all showing cometary features.
[MPEC 2025-D83, CBET 5509, 2025 February 22/24].
The comet is at perihelion at 14.1 au in 2028 May. Sam Deen noted on the comets-ml that this is a record perihelion
distance, which was previously held at 11.4 au by 2003 A2 (Gleason). He also said:
Perihelion distance aside, the 2018 images I've found of it establish it as a member of the very exclusive club of comets active beyond 20
au as well (2010 U3, 2014 UN271, 2017 K2, and 2019 E3). I have no idea how far out it was truly active because the 2018 images (taken by the 2.5-m Bok telescope) are the earliest publicly available archival images of its location. PANSTARRS may be able to push this date a bit further back, but regardless activity at 21.3
au from the Sun is very impressive indeed.
This comet is correspondingly dynamically new as well - the incoming barycentric aphelion is 56,600 +/- 4200
au using the observations I have. Unfortunately despite its very unusual (if not entirely unique) nature among comets, its high perihelion distance means it's not going to be getting very bright: considering its very slow magnitude slope from 2018-2025 I sincerely doubt it will get brighter than magnitude 20 as it passes perihelion in 2028. Of course, it will stay bright enough for targeted observations for many decades, so plenty of time to figure out more about this strange object.
2025 D2 (P/PANSTARRS)
PanSTARRS 2 discovered a 22nd magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
February 22.33. It was placed on the PCCP as P226VEQ. There were pre-discovery images from Mt Lemmon on
February 4, 19.
[MPEC 2025-D149, CBET 5510, 2025 February 24] The comet is at perihelion at 7.2 au in 2028 January and has
a period of somewhere around 30 years.
2025 D3 (P/PANSTARRS)
PanSTARRS 2 discovered a 22nd magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
February 22.43. It was placed on the PCCP as P2265Dx. There were pre-discovery images from PanSTARRS on
2024 December 30, 2025 January 6, February 6 and 7.
[MPEC 2025-D211, CBET 5513, 2025 February 26/27] The comet was at perihelion at 3.0 au in 2024 July and has
a period of around 8 years.
2025 D4 (P/ATLAS)
The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude object
in images taken with the 0.5 m Schmidt at Rio Hurtado, Chile on February 24.31. It was posted on the NEOCP as A11jANL.
Pre-discovery images were quickly found from PanSTARRS (2023 December 10, 14, 18, 23, 2024 January 5, February 6,
March 29, April 27, May 8, 22, 26, 2025 January 6) and ATLAS from the day before discovery.
[MPEC 2025-D235, CBET 5514, 2025 February 27/28]. The comet was near perihelion at 3.3 au and has a period of
around 27 years.
2025 D5 (PANSTARRS)
PanSTARRS 2 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
February 28.54. It was placed on the PCCP as P227rjs. There were pre-discovery images from Mt Lemmon on
February 20.
[MPEC 2025-E99, CBET 5519, 2025 March 5/6] The comet is at perihelion at 2.0 au in 2025 May.
The CBET gives the orbit as parabolic, which accords with the present
uncertainty. The MPC gives a long period orbit, whilst JPL call it a hyperbolic
comet.
2025 D6 (ATLAS)
The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude object
in images taken with the 0.5 m Schmidt at Rio Hurtado, Chile on February 26.27. It was posted on the NEOCP as A11jIls.
The cometary nature was reported by astrometrists.
[MPEC 2025-F22, CBET 5527, 2025 March 20]. The comet was at perihelion at 2.5 au in 2024 December.
2025 E1 (PANSTARRS)
PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
March 2.43. It was placed on the PCCP as P127ExT. There were pre-discovery images from PanSTARRS on January 3, 4, 25.
[MPEC 2025-E58, CBET 5518, 2025 March 3/4] The comet is at perihelion at 4.0 au in 2026 September.
2025 F1 (ATLAS)
The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude
comet
in images taken with the 0.5 m Schmidt at Rio Hurtado, Chile on March 22.04. It was posted on the
PCCP as A11kNtD.
The cometary nature was confirmed by astrometrists.
[MPEC 2025-G03, CBET 5534, 2025 April 1]. The intriniscally faint comet is at perihelion at 1.1 au in 2025 April.
2025 F2 (SWAN)
In an email to the comets-ml on April 1 Michael Mattiazzo reported a comet in SWAN images between March 22 and 29.
The estimated magnitude was between 10 and 11. Amateur observers then attempted ground based confirmation, with
Qicheng Zhang reporting success on April 2. Michael Mattiazzo was then able to find the comet in an image he
had taken on March 30. Many observers were then able to get the comet on the morning of April 3. Despite this, the
comet was not posted on the PCCP as of the morning of April 3. It was however
later posted on the NEOCP with a discovery date of April 3.1. The MPC did not formally recognise the comet
until April 8, when they essentially confirmed the orbit determined by amateurs five days earlier.
[MPEC 2025-G102, CBET 5538, 2025 April 8/9] The CBET is one of the longest that I can recall and notes that Vladimir Bezugly had
also informed the CBAT about the comet on March 29, with Rob Matson informing them on March 31. PanSTARRS were able to find
pre-discovery images from 2024 September 3, 9, 24, 27, October 4, 6. Sam Deen found images from 2024 September 8 in DECam data.
The MPEC assigns the discovery date to March 22.50. The comet is at perihelion at 0.3 au on May 1 and it is in a very long
period orbit.
The comet was predicted to brighten rapidly, though remaining at a relatively
small solar elongation, however the nucleus disintegrated and it became no brighter than around 9th magnitude.
It was initially a morning object, but then
become visible in the evening from around April 22. UK observers will loose it after May 1.
2025 H1 (P/NEAT)
Sam Deen found a probable recovery of 2003 QX29 in DECam images from 2024 September 1.
It was accidently recovered in images taken with the 1.5-m reflector of the Mt Lemmon Survey on April 23.45 at 20th
magnitude and posted on the PCCP as CD876E2. Pre-recovery images
from PanSTARRS on 2024 July 1 were then found. The previously published orbit required a correction of Delta(T) = -2.25 days.
The comet is at perihelion at 4.2 au in 2025 August and has a period of 22.6 years. [MPEC 2025-H183, CBET 5547, 2025 April 28]
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 equations for the light curves of comets that are currently visible
use only the raw observations and should give a reasonable prediction for
the current brightness. If the comet has not yet been observed or has
gone from view a correction for aperture is included, so that telescopic
observers should expect the comet to be fainter than given by the equation.
The correction is about 0.033 per centimetre. Values for the r parameter
given in square brackets [ ] are assumed. The form of the light curve is
either the standard m = H0 + 5 log d + K0 log r or the linear brightening
m = H0 + 5 log d + L0 abs(t - T + D0) where T is the date of perihelion,
t the present and D0 an offset, if L0 is +ve the comet brightens towards
perihelion and if D0 is +ve the comet is brightest prior to perihelion.
Observations of new comets in 2025 are given in ICQ format.
Full details of recently discovered objects will not appear until they are
available on the CBAT web pages. The actual accuracy of preliminary orbits is often
(nearly always) much worse than the published
accuracy implies. In part this is because
each orbital solution is treated as a mathematical construct and does not take account of observational
error. JPL does publish the errors,
whereas the MPECs do not.
Ephemerides of current comets are available on the CBAT
ephemeris page and positions of newly discovered comets are on the
NEO confirmation page.
More information on LINEAR. A list of comets
discovered by selected search programs.
The Northumberland refractor
is the telescope that was used in the search for Neptune.
It now has a 0.30-m f20 doublet lens which gives a stellar limiting magnitude of around
15 at the zenith on good nights.
The Thorrowgood refractor was
built in 1864 and has a 0.20-m f14 doublet lens.
Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk