BAA Comet Section : Comets discovered in 2023
Updated 2023 May 30
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 magnitude parameters [ updated 2023 January 3] of comets that are currently visible
should give a reasonable prediction for
the current brightness. The evidence shows that VEM magnitudes do
not require a correction for aperture. Visual observations however do, and
are therefore now corrected to a standard aperture of 30cm.
The correction is about 0.033 per centimetre. Visual observers using
smaller apertures may find a comet to be brighter than indicated by the
equation. 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 2023 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.
1808 R1 (Pons)
During research for their book on unconfirmed comets, Maik Meyer and Gary Kronk discovered manuscript letters from
Pons to B A von Lindenau at the Seeborg Observatory from 1808 September. These had sufficient information for them to be able to
derive positions and then for Syuichi Nakano to compute an orbit for a previously undocumented comet. This was at perihelion
at 1.1 au in 1808 September and was around 8th magnitude when observed. [CBET 5258, 2023 May 16]
1951 G1 (Groeneveld)
Ingrid Groeneveld of Yerkes Observatory discovered a 15th magnitude comet in 1954 January on a minor planet survey
plate taken with a 0.25m astrograph at the McDonald Observatory, Texas on 1951 April 2.17. In 2018 Maik Meyer
remeasured the original plate, finding that the original measurements had been for equinox 1900 and not as reported in
IAUC 1437 for equinox 1950.
In 2023 Maik Meyer, Gary Kronk and W H Osborn found the comet on
additional plates which had all been taken by H Rubingh and had been digitised. The MPEC says that these were taken for
the comet, but as they pre-date the discovery this is clearly an error. The comet was found on plates taken between
1951 March 31 and April 7. This allowed an orbit to be computed and the designation changed from X/ to C/. The
published orbit is however unbelievably accurate for such a short arc. The comet was at perihelion at 3.6 au in 1951 November.
[MPEC 2023-F18, CBET 5234, 2023 March 16]
1951 G2 = 1952 C1 (Groeneveld-Palomar)
Ingrid Groeneveld of Yerkes Observatory discovered a 16th magnitude comet in 1954 January on a minor planet survey
plate taken with a 0.25m astrograph at the McDonald Observatory, Texas on 1951 April 9.22. In 2018 Maik Meyer and Gary Kronk
remeasured the original plate, finding that the original measurements had been for equinox 1900 and not as reported in
IAUC 1437 for equinox 1950 and also that the sign of the declination was wrong.
Ronald Weinberger found a comet on a Palomar Sky Survey plate taken on on 1952 February 1.42 during a systematic search of the
plates. This was announced on IAUC 3246 [1978 July 18] as X/1952 C1. The plate was remeasured by Reiner Kracht in 2012.
In 2022 Maik Meyer investigated whether some X/ comets could be linked and found that this was possible for these two objects.
He and Gary Kronk then found the comet on
additional plates which had been taken on
1950 June 12, July 5, July 16 and 1951 April 7.
The designation for both objects was changed from X/ to C/.
The comet was at perihelion at 3.6 au in 1950 July.
[MPEC 2023-J76, CBET 5253 quickly replaced by 5254, 2023 May 10]
1971 M1 (Edwards)
Leonard R Edwards discovered a 9th magnitude comet on plates taken with the 0.5 m Baker-Nunn camera at the Mount John Observatory,
Lake Tekapo, New Zealand on 1971 June 19.59.
This was reported on an IAUC a year later, and no further observations were made. In 2023 Maik Meyer and Gary Kronk found the comet on
additional plates taken between 1971 June 20 and July 25 from South Africa which
had been digitised. This allowed an orbit to be computed and a designation
given. The
published orbit is again unbelievably accurate for such a short arc and an ephemeris is given for 2023 with the comet at 32nd magnitude.
The comet was at perihelion at 2.9 au in 1971 December.
[MPEC 2023-F148, CBET 5239, 2023 March 27]
2010 VH95 (P/Catalina)
The Catalina Sky Survey discovered a 19th magnitude asteroid with the 0.68m
Schmidt on 2010 November 7.49. Prediscovery observations were found from 1997 December and 1998 January (Air Force Maui Optical Station)
and 2010 October (Spacewatch). In 2023 Peter Veres of the MPC reported cometary features in images taken with the 0.5 m Schmidt at Rio Hurtado, Chile on
March 14, with archival images showing cometary activity back to January 16.The comet passed 0.10 au from Jupiter in 1937
January, 0.90 au from Jupiter in 2008 August and 0.24 au from Jupiter in 2020
February. It will also pass 0.37 au from Jupiter in 2032 April. [MPEC 2023-F167,
CBET 5240, 2023 March 27]. It has a period of 5.8 years and the most recent
perihelion was at 1.4 au in February. The Jupiter encounters are currently
pumping up the eccentricity and reducing the perihelion distance.
2014 OL465 (P/PanSTARRS)
Observations of a 22nd magnitude asteroidal object discovered by PanSTARRS 2014 July 25.43
were published on a MPS in 2022 March. There were also pre-discovery PanSTARRS observations
from 2012 March, published in 2023 February. Follow-up observations from ATLAS showed the
object to be brighter than expected and further observations in April and May showed a
coma and tail. It was therefore redesignated as a comet. It was at perihelion at 3.4 au
in 2023 February and has a period of 10.1 years.
[MPEC 2023-K66, CBET 5262, 2023 May 20]
2023 A1 (Leonard)
Gregory Leonard discovered a comet of 19th magnitude in images taken with the 1.5-m
reflector of the Mt Lemmon Survey on 2023 January 9.54.
It was placed on the PCCP as C8T3Z82.
[MPEC 2023-B66, CBET 5204, 2023 January 22]. The comet is at perihelion at 1.8 au in 2023 March.
2023 A2 (SWAN)
On January 26 Vladimir Bezugly reported on the comets-ml a possible faint comet
in SWAN images that he'd discovered on January 15 in images dating back to
January 6. A team of amateurs then went into action, confirming the comet and
eventually tracking it down in STEREO H1 images, which gave better astrometry.
Ground based imagers including Michael Mattiazo were able to locate it and only
then was it posted on the PCCP, which gave a preliminary designation of SWAN23A
and a discovery date of February 1.9. The comet was at perihelion at 0.9 au in January and was around
13th magnitude. It was formally confirmed on February 23 with the issue of
MPEC 2023-D49 and CBET 5226. The comet will fade, but might be observable in a dark sky
from southern hemisphere locations towards the end of the first week of March.
If the comet had returned to perihelion in early June it would have made a close
pass to the Earth later in the month, passing less than 0.05 au from us and
perhaps reaching naked eye visibility. The orbit MOID from Earth is 0.037
au. There is therefore the possibility
of a meteor shower from the comet in late June.
2023 A3 (Tsuchinshan-ATLAS)
The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered an 18th magnitude asteroidal object
in images taken with the 0.5 m Schmidt at Sutherland, South Africa on February 22.08. It was posted on the PCCP as A10SVYR
and follow up observations suggested that it was a comet. These enabled pre-discovery observations by ZTF on
December 22 to be found. The comet was linked to "isolated tracklet file" observations from Purple Mountain
Observatory on January 9.90, which had been posted on the NEOCP as one of X80918
or X80988, but with no follow up had been assumed lost
on January 30, when the object was removed.
[MPEC 2023-D77, CBET 5228, 2023 February 28/29]. The comet is at perihelion at 0.4 au in 2024 September.
The comet could become a visual telescopic object in 2024 February and will still be a telescopic
object for UK observers when lost in the summer twilight in June. If SOHO is still operational
it will pass through the C3 field as a bright object between about October 6 and 12. It
quickly emerges into the evening sky, when it could be an easily visible object with a tail. It
could remain a binocular object into December and a telescopic object into 2025. The MPC and CBAT
magnitude parameters make different assumptions and we should wait for more VEM observations
before making excitable predictions. The comet could turn out to be a
small one and disintegrate at perihelion.
2023 B1 (P/PanSTARRS)
PanSTARRS 2 discovered an 18th magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
January 21.48. It was placed on the PCCP as P21D3Eu. There were prediscovery images with ATLAS-HKO
on January 13 and Xingming Observatory #3, Nanshan on January 19. Alan Fitzsimmons suggests that it may
be a Centaur asteroid that is undergoing an outburst.
[MPEC 2023-B118, CBET 5209, 2023 January 25/26] The comet is at perihelion at 6.1 au in 2023 June and has a period
of around 20 years. It may have passed around 1 au from Jupiter in 1930
October.
2023 B2 (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 Sutherland, South Africa on January 21.97. It was posted on the PCCP as A10Scue.
There were pre-discovery PanSTARRS 1 images from 2022 November 16.
[MPEC 2023-C44, CBET 5217, 2023 February 7]. The comet is at perihelion at 1.7 au in 2023 March.
2023 B3 (P/PanSTARRS)
PanSTARRS 2 discovered an 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
January 23.43. It was placed on the PCCP as P21Ddk2.
[MPEC 2023-D10, CBET 5222, 2023 February 17] The comet was at perihelion at 4.0 au in 2020 August and has a period
of around 10 years. It passed around 0.12 au from Jupiter in 2005 April. The failure to discover it when
nearer to perihelion and the lack of any archival observations suggests that it may be in outburst.
2023 C1 (P/Jahn)
In mid March German amateur astronomer Jost Jahn discovered a comet in images he had taken with the 0.6m ROTAT
telescope of the Universitaet Tuebingen located at the Observatoire de Haute Provence on February 14.94. This
was reported to the MPC and posted on the PCCP as Lienen. The MPC then quickly found isolated tracklets from 2021
October and 2023 February. With a better orbit, additional images were soon found extending the arc back to 2016. A
PanSTARRS image on 2016 February 10.56 was used to give the designation 2016 C3.
The CBAT also asked Sam Deen to check and he found DECam images back to 2013 November.
[MPEC 2023-F123, CBET 5236, 5237, 2023 March 24] The comet was at perihelion at 2.6 au in 2022 October and has a period
of 7.6 years.
2023 C2 (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 1.25. It was posted on the PCCP as A10SuBN.
[MPEC 2023-F141, CBET 5238, 2023 March 26/27]. The comet is at perihelion at 2.4
au in 2024 November. The comet could reach 13th magnitude around the time
of perihelion, when it is at high southern declination.
2023 E1 (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 Sutherland, South Africa on March 1.00. It was initially posted on the NEOCP as A10TcmV,
but tranferred to the PCCP with a discovery date of 2022 December 25.5 when Peter Veres of the Minor Planet Centre linked it to
an isolated tracklet from February 26 by ATLAS (Chile). He was then able to link it to additional tracklets from Mt Lemmon (February 4),
PanSTARRS (January 22) and finally Kitt Peak-Bok (December 25) and show that the orbit was highly eccentric. Follow-up astrometry then
showed cometry features.
[MPEC 2023-E59, CBET 5233, 2023 March 12]. The comet is at perihelion at 1.0 au in 2023 July and has a period of around 85 years. It
will pass 0.4 au from the Earth in 2023 August, but is intrinsically faint and is not predicted to be brighter than 14 magnitude.
2023 F1 (PanSTARRS)
PanSTARRS 1 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
March 27.60. It was placed on the PCCP as P11Ebg3. There were prediscovery images with PanSTARRS 2
on March 18.
[MPEC 2023-H184, CBET 5247, 2023 April 26] The comet is at perihelion at 1.7 au in 2023 June.
2023 F2 (PanSTARRS)
Hanjie Tan discovered a Meyer group comet in SOHO C3 images on March 21. Karl Battams and Hanjie Tan measured positions from
March 21.00 to 21.61 from which Bill Gray computed a parabolic orbit. Despite the very short arc, the MPC decided to produce
a hyperbolic orbit, something not justified by the data. The comet was at perihelion at 0.034 au when observed.
[MPEC 2023-K46, 2023 May 18].CBET 5261 [2023 May 19] also recommends
disgregarding the MPC orbit.
2023 G1 (P/NEOWISE-SWAN)
On April 16 Rob Matson discovered an object in SWAN images taken between April 5 and 15. Michael Mattiazzo confirmed it with a ground
based observation on April 18. Follow up by the amateur community fairly quickly established a link with 2018 HT3, an Apollo asteroid
discovered by NEOWISE on 2018 April 22.96. PanSTARRS observations from 2012 September, October and 2013
June were subsequently found. The
object was recovered in 2022 November by Spacewatch II. Sam Deen noted that it might be visible in SWAN imagery from 1997 August,
2002 September, 2007 October, 2012 December and 2018 January. It was also visible in STEREO images from 2012 November.
The comet is past perihelion but
approaching Earth. It is estimated at around 13th magnitude and
won't get any brighter but the elongation will improve. It is at high southern
declination. This object probably won't receive the above designation as the MPC use a different logic to that used by Brian Marsden
who devised the system.
2023 H1 (PanSTARRS)
PanSTARRS 2 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
April 17.35. It was placed on the PCCP as P21EEX6.
[MPEC 2023-J101, CBET 5256, 2023 May 12] The comet is at perihelion at 4.5 au in 2024 November.
2023 H2 (Lemmon)
A possible NEO candidate of 21st magnitude was discovered on 2023 April 23.28 in images taken with the 1.5-m
reflector of the Mt Lemmon Survey. It was placed on the PCCP as C95VDX2. Subsequently other astrometrists reported
that it had cometary features. There were pre-discovery PanSTARRS images from March 26 and April 18.
[MPEC 2023-K122, CBET 52xx, 2023 May 24]. The comet is at perihelion at 0.9 au in 2023 October. After
perihelion it passes 0.2 au from the Earth when it may reach 10th magnitude. It will then be in the
evening sky and moving rapidly south.
2023 H3 (PanSTARRS)
PanSTARRS 2 discovered a 21st magnitude comet in images taken with the 1.8 m Ritchey-Chretien on
April 28.40. It was placed on the PCCP as P21EXHF.
There were pre-discovery PanSTARRS observations from March 16, 31, April 15 and
21. [MPEC 2023-K195, CBET 5267, 2023 May 30] The comet is at perihelion at 5.2 au in 2024 February and
has a period of around 50 years. If the orbit is correct Syuichi Nakano notes
that the comet would have passed 0.005 au from Uranus in 1938 November, before
which the comet had perihelion at 6.2 au in 1924 October and a period of 66
years.
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 very 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