BAA Comet Section : Comets discovered in 2025
Updated 2025 January 19
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.
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