BAA Comet Section : Comets discovered in 2018
Updated 2023 October 24
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 comets made in 2018 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.
2007 KP2 [A/ATLAS]
An object was discovered in images taken with the 0.5m Schmidt at Haleakala on April 13
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It was posted on the PCCP as A106HZo.
The object was linked by the MPC with 2007 KP2, an Outer Main-belt Asteroid observed between 2007 April 22
and May 20.
2018 A1 (PanSTARRS)
A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January
6.58. It was placed on the PCCP as P10FSoC. Peter Birtwhistle
confirmed the cometary nature of the discovery.
[CBET 4471, MPEC 2018-A43, 2017 January 11] Astrometry from Nick James and Peter Carson later in January
allowed Nick to compute a revised orbit which suggested that the comet had a
period of around 130 years and was at perihelion at 2.4 au in 2017 October.
This was confirmed in an MPEC that came out a few days later.
2018 A2 (364P/PanSTARRS)
Erwin Schwab reported the recovery of 2013 CU129 to the Central Bureau in remotely obtained
images that he had taken with the 0.8m Schmidt at Calar Alto, Spain, on January 16.92. In the
meantime Gareth Williams of the Minor Planet Centre had identified the comet in incidental
astrometry from Mt Lemmon on January 12.38. As is becomming commonplace, two CBETs were
required to correctly announce the recovery. [CBET 4474, 4475, MPEC 2018-B14, 2018 January 17]
The indicated correction to the prediction by S. Nakano in the ICQ's 2018
Comet Handbook is Delta(T) = +0.02 day.
2018 A3 (ATLAS)
An 18th magnitude comet was discovered in images taken with the 0.5m Schmidt at Mauna Loa on January 10.61
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It had been posted on the PCCP as A105UPd.
[CBET 4476, MPEC 2018-B18, 2018 January 17]. The comet will reach perihelion at 3.3 au in 2019 January.
2018 A4 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on January 12.29.
It had been posted on the PCCP as P10G1vh.
[CBET 4477, MPEC 2018-B19, 2018 January 17] The comet is at perihelion at 2.4 au in 2018
May. It has a period of around 45 years (calculated by Hirohisa Sato) and JPL classify it as a Jupiter-family comet.
The preliminary orbit has a Jupiter MOID of 0.15 au, though there have been no recent close passes.
2018 A5 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on January 13.47. There were pre-discovery PanSTARRS images
from 2017 November and December.
It had been posted on the PCCP as P10G50L.
[CBET 4478, MPEC 2018-B20, 2018 January 17] The comet was at perihelion at 2.7 au in 2017
September. It has a period of 13.4 years and JPL classify it as a Jupiter-family comet.
2018 A6 (Gibbs)
Alex Gibbs discovered a 19th magnitude comet in Mt Lemmon Survey images taken
with the 1.5m reflector on January 15.38. It was placed on the PCCP as ZAA01CF.
[CBET 4479, MPEC 2018-B100, 2018 January 23] Hirohisa Sato suggested that the comet
might be periodic. The comet is at perihelion at 3.0 au in 2019 July and has a
period of around 60 years.
A/2017 AS18 [Mt Lemmon]
The Mt Lemmon Survey discovered an asteroid in images taken with the 1.5m
reflector on January 13, which was posted on the PCCP as ZA398B0. There is currently no evidence for cometary activity.
The asteroid is classified as a Centaur by JPL.
It is at perihelion at 1.7 au in 2018 March and has a period of around 50 years, though unusually JPL do not
give any error bars.
2018 B1 (Lemmon)
An apparently asteroidal object of 19th magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on January 25.14. It was placed on the PCCP
as ZBB6FE2 and follow up observations by astrometrists, including Peter Birtwhistle, showed that it was
slightly diffuse and elongated. With a preliminary orbit, Gareth Williams was then able to find
pre-discovery PanSTARRS images from 2017 January.
[CBET 4484, MPEC 2018-C27, 2018 February 7] The comet is at perihelion at 5.1 au in 2018 March.
A/2018 BJ11 [PanSTARRS]
PanSTARRS discovered an asteroid in images taken with the 1.8m Ritchey-Chretien in
January. The object, classified as an Outer Main-belt Asteroid,
was at perihelion at 3.3 au in 2015 November and has a period of around 9 years.
It was placed on the PCCP as P10GpOj. No cometary activity has been confirmed.
2018 C1 (P/Lemmon-Read)
Mike Read discovered a comet in images taken with the 0.9-m Spacewatch telescope
at Kitt Peak on February 9.29. It was also discovered as an
apparently asteroidal object of 19th magnitude and possible NEO, in Mt Lemmon
Survey images taken with the 1.5m reflector on February 4.42. It was placed on
the PCCP as SW40xg. After posting it was also found in PanSTARRS images
from January 16.42. [CBET 4487, MPEC 2018-C76, 2018 February 11] The comet is
near perihelion at 2.59 au and has a period of around 13 years.
2018 C2 (Lemmon)
An asteroidal object of 20th magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on February 5.55. It was placed on the PCCP
as ZC82561, because it had a slightly hyperbolic orbit, but no cometary activity had been detected.
It was therefore given a cometary letter designation with an A/ prefix.
[MPEC 2018-E18, 2018 March 4] On March 22.6 images taken with the 3.6m Canada-France-Hawaii
showed a broad faint tail, though with only a marginal coma. The designation was therefore
changed to C/ [MPEC 2018-F136, CBET 4501, 2018 March 28]
The comet is at perihelion at 2.0 au in 2018 June.
2018 DO4 (Lemmon)
An asteroidal object of 21st magnitude was found in Mt Lemmon Survey images
taken with the 1.5m reflector on February 25.31. It was placed on the PCCP as
ZD9686E, but no cometary activity was detected at the time. [MPEC 2018-F13, 2018
March 16] Cometary activity was subsequently detected in 2019 August and
September and it was then designated as a comet. [CBET 4675, MPEC 2019-T99, 2019
October 6] The comet was at perihelion at 2.4 au in 2019 August and has a
retrograde orbit with a period of around 130 years.
2018 DE4 [A/Lemmon]
An asteroidal object of 21st magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on February 17.43. It was placed on the PCCP
as ZD8BAB2, but no cometary activity has been detected.
[MPEC 2018-E15, 2018 March 4] The asteroid is at perihelion at 2.4 au in 2018 April and has a period
of around 180 years. It is classified as a TransNeptunian Object by JPL.
2018 DF4 [A/Lemmon]
An asteroidal object of 21st magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on February 23.22. It was placed on the PCCP
as ZD92B16, but no cometary activity has been detected.
[MPEC 2018-E16, 2018 March 4] The asteroid is at perihelion at 1.6 au in 2018 October and has a period
of around 1000 years. It is classified as a TransNeptunian Object by JPL.
2018 E1 (ATLAS)
A 17th magnitude comet was discovered in images taken with the 0.5m Schmidt at Haleakala on March 10.23
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. Pre-discovery images from PanSTARRS were found
in data from 2015 August and October and 2016 August to October. It had been posted on the PCCP as A106x1X.
[CBET 4493 and quickly revised on 4494, MPEC 2018-F10, 2018 March 16]. The comet will reach perihelion at 2.7 au in 2018 April and has a
period of around 400 years.
2018 E2 (Barros)
Brazilian amateur astronomer Joćo Ribeiro de Barros discovered a 19th magnitude comet in images taken with
the 0.45m f/2.9 reflector of the SONEAR observatory on March 12.93. [CBET 4495, MPEC 2018-F11, 2018 March 16]
It had been posted on the PCCP as S091272.
The comet was at perihelion at 3.9 au in 2017 December.
2018 EN4 (NEOWISE)
A 20th magnitude object was discovered from the NEOWISE satellite on March 9.09. [MPEC 2018-F12, 2018 March 16]
It had been posted on the PCCP as N00ctza.
The object, originally classified as a Centaur asteroid, was at perihelion at 1.4 au in 2018
June and has a highly inclined orbit with a period of around 80 years. The
orbit has a Jupiter MOID of 0.57 au and a Tisserand invariant of 0.43. As it approached perihelion it
developed cometary activity, and was redesignated as a comet. [MPEC 2018-L53, CBET 4524, 2018 June 11
and CBET 4525 the same day with replacement text]
2018 EF9 (Lemmon)
An asteroidal object of 21st magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on March 9.30. It was placed on the PCCP
as ZE9BC93, but no cometary activity was detected at the time.
[MPEC 2018-F138, 2018 March 28]
Further observations in April, first by NEOWISE and then confirmed from the ground showed a coma
and faint tail, so the object was redesignated as a comet. [CBET 4511, MPEC 2018-H55, 2018 April 20]
The comet is at perihelion at 1.6 au in 2018 May and has a period
of around 12,000 years. The inclination of the orbit is near perpendicular.
It has a Jupiter MOID of 0.24.
Juan Jose Gonzalez found it much
brighter than expected when it reached perihelion, making it 11th magnitude in
his 20cm SCT from his mountain observing site.
2018 F1 (Grauer)
Al Grauer discovered a comet of 19th magnitude in Mt Lemmon Survey images taken with the
1.5m reflector on March 17.35. It was independently discovered a few hours later in PanSTARRS images
[So why isn't it Grauer-PanSTARRS ?] and they also found pre-discovery images from 2017 December 22,
2018 January 17 and March 10.
[CBET 4496, MPEC 2018-F42, 2018 March 19] The comet is at perihelion at 3.0 au in 2018 December. It
has a period of around 5000 years.
2018 F2 (366P/Spacewatch)
2005 JN was recovered with the 1.0m f/4.4 reflector at the ESA Optical Ground Station at Tenerife on
March 17.18. It was 20th magnitude.
2018 F3 (Johnson)
Jess Johnson discovered a comet of 20th magnitude in Mt Lemmon Survey images taken with the
1.5m reflector on March 20.27. It was placed on the PCCP
as ZFAB135.
[CBET 4500, MPEC 2018-F137, 2018 March 28] The comet was at perihelion at 2.5 au in 2017 August.
2018 F4 (PanSTARRS)
PanSTARRS discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
March 17.53. It was placed on the PCCP as P10HIgx but no cometary activity was confirmed at the time.
The object was classified as a Hyperbolic Asteroid by JPL.
Evidence for a cometary nature came in April, when follow up images showed a coma and tail. [MPEC 2018-
H21, CBET 4508, 2018 April 17]. The comet is at perihelion at 3.4 au in 2019 December and has a current eccentricity of 1.0015 in a near
perpendicular orbit.
The Jupiter MOID is 0.60, but the object is not currently near the planet. It
could be a candidate for a second interstellar object as the latest orbit
remains strongly hyperbolic.
Taras Prystavski reported on comets-ml that there were
two components in images taken on 2020 September 12. On September 18
Man-To Hui reported that images suggested suggested that the separation had
occurred at least two months previously. The breakup was confirmed in MPEC 2020-S77 [2020 September 19]. It gives
orbits for the two components, but these are based on a five day arc only and are
probably physically unrealistic, with perihelion dates differing by seven
months, perihelion distances by 1.5 au and inclinations by 10 degrees. As
expected as soon as the additional positions were included in the orbital
determination [CBET 4852, 2020 September 19] the differences disappeared.
Syuichi Nakano suggests that the separation of the two components probably
occurred around the time of perihelion.
2018 H1 (367P/Catalina)
Erwin Schwab recovered 2011 CR42 during remote observations with the Calar Alto 0.8m Schmidt
on April 17.01. No tail or coma was detected in total exposures of 600s.
2018 H2 (P/PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on April 16.53. There were pre-discovery PanSTARRS images
from 2017 November.
It had been posted on the PCCP as P10Hq33.
[CBET 4512, MPEC 2018-H93, 2018 April 26] The comet was at perihelion at 2.0 au in 2018
January. It has a period of 9.2 years and JPL classify it as a Jupiter-family comet.
2018 HT3 (P/NEOWISE)
A 19th magnitude object was discovered from the NEOWISE satellite on 2018 April 22.96.
The object was at perihelion at 0.5 au in 2018
April and seemed to be a typical NEO. It was found to be cometary at the 2023 return.
2018 K1 (Weiland)
Henry Weiland discovered a 17th magnitude comet in images taken with the 0.5m Schmidt at Mauna Loa on May 25.54
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) program. Pre-discovery images from PanSTARRS were found
in data from 2017 November 6 and 2018 May 24. It had been posted on the PCCP as A1072Wf.
[CBET 4518, MPEC 2018-K117, 2018 May 31]. The comet was at perihelion at 1.8 au in 2018 April and has a
period of around 160 years.
2018 KJ3 (Lemmon)
An asteroidal object of 20th magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on May 17.41. It was placed on the PCCP
as ZKA8FB3, but no cometary activity was detected at the time.
[MPEC 2018-K116, 2018 May 31] When observed in August with the 3.6-m Canada-France-Hawaii Telescope it showed a clear tail
and coma. [MPEC 2018-P84, 2018 August 13] The comet is at perihelion at 3.6 au in 2019 September and has a
retrograde orbit with a period of around 2000 years.
A/2018 KH3 [Lemmon]
An asteroidal object of 21st magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on May 16.43. It was placed on the PCCP
as ZKA7A2D, but no cometary activity has been detected.
[MPEC 2018-K115, 2018 May 31] The asteroid was at perihelion at 3.7 au in 2017 May and has a
period of around 1000 years. It is classified as a Trans Neptunian Object by JPL.
A/2018 KA4 [PanSTARRS]
PanSTARRS discovered an asteroid in images taken with the 1.8m Ritchey-Chretien
on
May 23. The object, classified as a Mars-crossing Asteroid, was at perihelion
at 1.6 au in 2018 June and has a period of around 3.9 years.
It was placed on the PCCP as P10HxLa. No cometary activity has been confirmed.
A/2018 KB4 [PanSTARRS]
PanSTARRS discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on
May 26.57. The object, classified as a Apollo Asteroid,
was at perihelion at 1.0 au in 2018 April and has a period of around 3.3 years.
It was placed on the PCCP as P10Hy2h. No cometary activity has been confirmed.
2018 L1 (P/PanSTARRS)
A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on June 3.28. It was placed on the PCCP as P10HyFo. [CBET
4521, MPEC 2018-L36, 2018 June 8] The comet has a period of around 7.0 years and is at perihelion at 1.9 au in 2018 November.
2018 L2 (ATLAS)
A 16th magnitude comet was discovered in images taken with the 0.5m Schmidt at
Mauna Loa on June 6.33
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It had been posted on the PCCP as A1077xy.
[CBET 4522, MPEC 2018-L37, 2018 June 9]. The comet will reach perihelion at 1.7
au in 2018 December. It was much brighter than expected when observed by
JJ Gonzalez in early October and already 10th magnitude.
2018 L3 (368P/NEAT)
2005 R1 was recovered in images taken at the European Space Agency's Optical Ground Station at Teneriffe
with the 1.0m reflector on June 13.19. It was 19th magnitude. The indicated correction to the prediction
by S. Nakano in the ICQ's 2018 Comet Handbook is Delta(T) = -0.07 day. [CBET 4526, MPEC 2018-L76, 2018 June 14]
2018 L4 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on June
8.51. It was placed on the PCCP as P10HIxG.
[CBET 4527, MPEC 2018-M83, 2018 June 22] The comet has a
period of around 11 years and is at perihelion at 1.7 au in 2018 July.
2018 L5 (P/Leonard)
Greg Leonard discovered a comet of 19th magnitude in Mt Lemmon Survey images taken with the
1.5m reflector on June 14.42. It was placed on the PCCP
as ZLB3D4B.
[CBET 4528, MPEC 2018-N04, 2018 July 1] The comet was at perihelion at 2.3 au in 2018 May
and has a period of around 6.9 years.
2018 M1 (Catalina)
A 17th magnitude comet was discovered by the Catalina Sky Survey with the 0.68m Schmidt on June 25.43.
[CBET 4529, MPEC 2018-N05, 2018 July 2] It had been posted on the PCCP as ZM2A6E9.
The comet was at perihelion at 1.3 au and has a period of around 100 years.
A/2018 MO8 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
June 16.27. The object, classified as a Centaur,
is at perihelion at 5.0 au in 2018 December and has a period of around 60 years.
It was placed on the PCCP as P10HTOF. No cometary activity has been confirmed.
A/2018 MP8 [PanSTARRS]
PanSTARRS discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on
June 16.51. The object, classified as a Trans Neptunian Object,
was at perihelion at 3.8 au in 2018 February and has a period of around 6000 years.
It was placed on the PCCP as P10HUAa. No cometary activity has been confirmed.
2018 N1 (NEOWISE)
A 16th magnitude cometary object was discovered from the NEOWISE satellite on July 2.37. [MPEC 2018-N18
CBET 4531, 4532, 2018 July 6] It was posted on the PCCP as N00ddem. The comet is at perihelion at 1.3 au in 2018
August. Although not predicted to come with in visual range, it might appear brighter
to visual observers - this suggestion was evidently correct, as there are
reports that the comet is around 11 - 12 magnitude.
2018 N2 (ASASSN)
The All-Sky Automated Survey for Supernovae (ASASSN) discovered a 16th magnitude comet with the "Cassius" 14cm telescope at Cerro Tololo on
July 7.39. [CBET 4534, MPEC 2018-O1, 2018 July 16] The comet reached perihelion at 3.1 au in 2019
November, when it was 11th magnitude.
A/2018 NZ14 [Lemmon]
An asteroidal object of 20th magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on July 5.40. It was placed on the PCCP
as ZNB9415, but no cometary activity was detected.
The asteroid was at perihelion at 1.4 au in 2018 June and has a
period of around 4.3 years. It is classified as a Mars-crossing Asteroid by JPL.
2018 O1 (ATLAS)
A 19th magnitude object was discovered in images taken with the 0.5m Schmidt at Mauna Loa on July 22.55
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. Pre-discovery images from the 1.2m Schmidt at Palomar were found
in data from earlier in July. Confirmation took some time because some larger telescopes did not see cometary features.
Other observers, including Peter Birtwhistle, were able to distinguish a difference from stars. It had been posted on the PCCP as A107IQ9.
[CBET 45xx, MPEC 2018-Q22, 2018 August 17]. The comet is near perihelion at 1.6 au in 2018 April and has a
period of around 150 years.
2018 P1 (369P/Hill)
Erwin Schwab reported the recovery of 2010 A1 in
images taken with the 1.0m reflector at the European Space Agency's Optical
Ground Station at Teneriffe on August 10.18. [CBET 4538, MPEC 2018-P80, 2018 August 13]
The MPEC says "The 2018 prediction by B. G. Marsden on MPC 94681
required a correction in T of +0.39 days." A better phrasing might be
"The prediction for the 2018 return by B. G. Marsden on MPC 94681 required a correction in T of +0.39 days."
2018 P2 (370P/NEAT)
Erwin Schwab reported the recovery of 2001 T3 in
images taken with the 1.0m reflector at the European Space Agency's Optical
Ground Station at Teneriffe on August 10.20. [CBET 4539, MPEC 2018-P81, 2018 August 13]
The prediction for the return by Gareth Williams on MPC 94679
required a correction in T of -1.16 days.
2018 P3 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on August 8.54.
It had been posted on the PCCP as P10IPdp.
[CBET 4548, MPEC 2018-Q34, 2018 August 19] The comet was at perihelion at 1.8 au in 2018
October. It has a period of around 5.2 years and JPL classify it as a Encke-type comet.
2018 P4 (P/PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on August 8.50.
It had been posted on the PCCP as P10IRIJ.
[CBET 4549, MPEC 2018-Q35, 2018 August 19] The comet is at perihelion at 3.7 au in 2018
November. It has a period of around 17 years and JPL classify it as a Jupiter-family comet.
2018 P5 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on August 11.45.
It had been posted on the PCCP as P10IX2S.
[CBET 4550, MPEC 2018-Q36, 2018 August 19] The comet is at perihelion at 4.6 au in 2019
February. It has a period of around 45 years and JPL classify it as a Jupiter-family comet.
The preliminary orbit has a Jupiter MOID of 0.21 au, though there have been no recent close passes.
2018 P6 (372P/McNaught)
Gareth Williams recovered 2008 O2 (P/McNaught) in astrometric data submitted by PanSTARRS
(PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 8.50) and
the Gaia-GBOT team (images taken with the 2.6m Ritchey-Chretien at Cerro Paranal on September 6.13).
The comet was apparently stellar in appearance. [CBET 4554, MPEC 2018-S01, 2018 September 16]
The prediction for the return by Gareth Williams on MPC 94681
required a correction to T of -0.52 days.
2018 PB [A/ATLAS]
An object was discovered in images taken with the 0.5m Schmidt at Haleakala on August 1
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It was posted on the PCCP as A107Q4R.
It is a Mars-crossing Asteroid with a period of 3.6 years and a perihelion distance of 1.6 au in 2018 July.
No cometary activity has been confirmed.
2018 PH10 [A/PanSTARRS]
An object was discovered in images taken with the 1.8m Ritchey-Chretien on August 9
by the PanSTARRS team. It was posted on the PCCP as P10ISme.
It is a Mars-crossing Asteroid with a period of 4.7 years and a perihelion distance of 1.5 au
in 2019 February. No cometary activity has been confirmed.
2018 PL28 [A/PanSTARRS]
A 22nd magnitude object was discovered in images taken with the 1.8m Ritchey-Chretien on August 7.54
by the PanSTARRS team. It was posted on the PCCP as P10IJXB.
It is a Centaur with a period of around 90 years and a perihelion distance of 2.7 au
in 2017 July. It approached Jupiter to 0.5 au in 2016 February. No cometary activity has been confirmed.
2018 R1 (371P/LINEAR-Skiff)
Erwin Schwab reported his recovery of 2001 R6 in
images taken with the 1.0m reflector at the European Space Agency's Optical
Ground Station at Teneriffe on September 7.09. The comet was not recovered at the 2010 return.
The correction to T compared to the 2013 MPEC prediction is +0.36 days.
[CBET 4552, MPEC 2018-R59, 2018 September 8]
2018 R2 (373P/Rinner)
Jean-Francois Soulier (0.3m Newtonian f/4 reflector at Maisoncelles, September 9.03) and Krisztian Sarneczky
(0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly), September 14.11) independently recovered 2011 W2.
The prediction for the return by Gareth Williams on MPC 102105 required a correction to T of -0.43 days.
[CBET 4555, MPEC 2018-S03, 2018 September 16]
2018 R3 (Lemmon)
An apparently asteroidal object of 19th magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on September 7.16. It was placed on the PCCP as ZRBBF83 and
follow up observations by astrometrists showed that it was
slightly diffuse and elongated. With a preliminary orbit, Gareth Williams was then able to find
pre-discovery PanSTARRS images from 2018 August.
[CBET 4556, MPEC 2018-S04, 2018 September 16] The comet was at perihelion at 1.3 au in 2019
June, when it reached 10th magnitude.
2018 R4 (Fuls)
D Carson Fuls discovered a 19th magnitude comet in images taken with the Catalina Sky Survey 0.68m Schmidt on September 9.31.
There were pre-discovery images from August in Purple Mountain Observatory data.
[CBET 4557, MPEC 2018-S05, 2018 September 16] It had been posted on the PCCP as ZR393C1.
The comet was at perihelion at 1.7 au in 2018 March.
2018 R5 (Lemmon)
An apparently asteroidal object of 19th magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on September 8.23. It was placed on the PCCP as ZR82175 and
follow up observations by astrometrists showed that it was
slightly diffuse and elongated. With a preliminary orbit, Gareth Williams was then able to find
pre-discovery PanSTARRS images from 2018 July and August.
[CBET 4559, MPEC 2018-S38, 2018 September 18] The comet is at perihelion at 3.6 au in 2019
January and has a period of around 110 years.
2018 S1 (374P/Larson)
Krisztian Sarneczky and Robert Szakats
(0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly)) recovered 2007 V1 on September 18.00.
The prediction for the return by Gareth Williams on MPC 102104 required a correction to T of -1.17 days.
[CBET 4558, MPEC 2018-S31, 2018 September 18]
2018 S2 (TESS)
An asteroidal object of 19th magnitude was found in TESS (Transiting Exoplanet Survey Satellite) images released in 2022 but taken on
2018 September 23.78. It was posted on the PCCP as LTMMK8P in 2022 August as it had a cometary orbit.
Kevin Ly (El Monte, California) helped
by Sam Deen, then found pre-discovery images from 2017 August in "SkyMapper" data from the 1.35-m telescope at Siding
Spring, from 2017 October in data from the 2.65-m Ritchey-Chretien reflector at Cerro Paranal and in DECam images with the
Cerro Tololo 4-m reflector between 2017 August and 2019 March. These showed cometary activity.
[MPEC 2022-Q126, CBET 5163, 2022 August 26]. The comet was at perihelion at 5.5 au in 2018 November and has a period of 54 years.
2018 S3 (TESS)
Sam Deen noted cometary activity in prediscovery images taken on September 9
with the
DECam on the 4-m Cerro Tololo reflector of an asteroidal object of 19th magnitude found in TESS
(Transiting Exoplanet Survey Satellite) images released in 2022 but taken on
2018 September 22.39. He then found further images of the object back to 2014 February. It was posted on the PCCP as LTKzzDH in 2022 August
as it had a cometary orbit. There it languished until 2023 February, when an orbit was finally published.
[MPEC 2023-D54, CBET 5229, 2023 February 24/March 1]. The comet was at perihelion at 8.0 au in 2016 June.
A/2017 SQ13 [Mt Lemmon]
The Mt Lemmon Survey discovered an asteroid in images taken with the 1.5m
reflector on September 21.39, which was posted on the PCCP as ZS9F67C. There is currently no evidence for cometary activity.
The asteroid is classified as a TNO by JPL.
It was at perihelion at 3.0 au in 2018 August and has a perpendicular orbit with a period of around 2000 years.
2018 T1 (375P/Hill)
Krisztian Sarneczky (0.6m Schmidt and 1.02m Ritchey-Chretien at the University of Szeged, Piszkesteto Station (Konkoly)) recovered 2006 D1 on October 5.10.
The prediction for the return by Gareth Williams on MPC 94682 required a correction to T of -0.22 days.
[CBET 4560, MPEC 2018-T62, 2018 October 6]
A/2017 TL6 [Mt Lemmon]
The Mt Lemmon Survey discovered an asteroid in images taken with the 1.5m
reflector on October 5.30, which was posted on the PCCP as ZTAAD63. There is currently no evidence for cometary activity.
The asteroid is classified as a Centaur by JPL.
It is at perihelion at 1.7 au in 2018 December and has a retrograde orbit with a period of around 25 years.
2018 U1 (Lemmon)
An apparently asteroidal object of 20th magnitude was found in Mt Lemmon Survey images taken with the
1.5m reflector on October 27.19. It was placed on the PCCP
as ZU8D586 and follow up observations by astrometrists, including Peter Birtwhistle
and Werner Hasubick, showed that it was
slightly diffuse.
Gareth Williams notes on the MPEC: This object was reported as a new NEO and was moved to the PCCP when the
orbit looked cometary. Early reports from some observers using small
telescopes implied that the object was, in fact, a comet, but these reports
were not confirmed at the time by observers using large telescopes. Responding
to a query from the MPC, W. Ryan (H01, 2.4-m reflector) remarked that his
Oct. 27 images showed a subtle cometary appearance, and that the Nov. 19 images
had a PSF ~ 1.5 times that of field stars and a slightly elongated coma or tail
in P.A. 35.
[CBET 4574, MPEC 2018-W42, 2018 November 20] The comet is at perihelion at 5.0 au in 2021 November.
2018 V1 (Machholz-Fujikawa-Iwamoto)
Don Machholz visually discovered a 10th magnitude comet on November 7.53 with a 0.47m reflector from Colfax, CA. This was his 12th discovery,
with 746 hours of searching since his last. Two Japanese CCD imagers also discovered the comet, with Shigehisa Fujikawa (Kan'onji, Kagawa, Japan),
finding it in images taken on November 7.82 and Masayuki Iwamoto (Awa, Tokushima, Japan) in images taken on November 7.84.
[CBET 4569, 2018 November 8] Despite the CBET being issued on November 8,
the MPEC giving the orbit issued on November 11 stated that the MPC was not
informed about the Japanese discovery until November 10.55. [CBET
4572, MPEC
2018-V151, 2018 November 11]. The comet is nearing perihelion at 0.4 au in
early December and should brighten. The orbit has an Earth MOID of 0.11 au. The comet will remain in the
early morning sky until the end of the month, when it will switch to the early
evening. It's elongation from the Sun is likely to remain small. In the event the comet
has not brightened much since discovery.
2018 V2 (ATLAS)
A 19th magnitude object was discovered in images taken with the 0.5m Schmidt at Mauna Loa on November 2.53
by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. Suggested as an NEO candidate, a weak coma
was reported from PanSTARRS 1 images (according to the MPEC though only PanSTARRS 2 positions are given in the MPEC
and mentioned in the CBET so this is presumably a typographical errror) on November 6, before
the discovery of 2018 V1. It had been posted on the PCCP as A109AGz.
[CBET 4578, MPEC 2018-X10, 2018 December 1]. The comet was at perihelion at 2.5 au in 2018 November and has a
period of 130 years. An updated orbit was published on MPEC 2019-Q03 [2019
August 16], which (wrongly) names the comet as Trujillo-Sheppard.
2018 V3 (A/PanSTARRS)
A 22nd magnitude object was discovered in images taken with the 1.8m
Ritchey-Chretien on November 12.40 by the PanSTARRS team. It was posted on the
PCCP as P20KiDU. [CBET 4579, MPEC 2018-X12, 2018 December 1] It is in a long
periodic orbit with a perihelion distance of 1.3 au in 2019 September.
Alan Hale reports that he did not detect any cometary appearance in images.
2018 V4 (Africano)
Brian Africano discovered a comet of 20th magnitude in Mt Lemmon Survey images taken with the
1.5m reflector on November 4.43. It was placed on the PCCP as ZVAIB24.
[CBET 4579, MPEC 2018-X13, 2018 December 1] The comet is at perihelion at 3.2 au in 2019 March.
2018 V5 (P/Trujillo-Sheppard)
Chad Trujillo discovered a comet of 22nd magnitude in images taken by Scott Sheppard with the 8.2m Subaru telescope on Mauna Kea on November 6.52.
It was placed on the PCCP as K899708. There were pre-discovery PanSTARRS images from 2017 September, October, November and 2018 August.
[CBET 4607, MPEC 2019-C18, 2019 February 3] The comet was at perihelion at 4.7 au in 2018 October and has a period of around 27 years.
2018 VN2 (P/Leonard)
Greg Leonard discovered a comet of 19th magnitude in Mt Lemmon Survey images taken with the
1.5m reflector on November 5.38. Gareth Williams notes on the MPEC:
This object was reported as a comet by G. J. Leonard (G96, 1.5-m reflector)
on Nov. 5. He noted a 3"-5" coma and a broad 8" tail in P.A. 280-290, as seen
in 4 co-added 30s exposures. Due to the ADES work currently underway at the
MPC, the object was not moved to the PCCP, and it was later designated as a
non-NEO minor planet.
[CBET 4573, MPEC 2018-W18, 2018 November 18] The comet was at perihelion at 2.1 au in 2018 June
and has a period of around 8.2 years.
2018 VL10 [A/PanSTARRS]
A 21st magnitude object was discovered in images taken with the 1.8m Ritchey-Chretien on November 9.50
by the PanSTARRS team. [MPEC 2018-W87, 2018 November 30] It was posted on the PCCP as P20KdRI.
It is an Outer Main-belt Asteroid with a period of 9.9 years and a perihelion distance of 1.4 au
in 2018 December. No cometary activity has been confirmed. It has a
Jupiter MOID of 0.08 au.
2018 W1 (Catalina)
A 20th magnitude object was discovered by the Catalina Sky Survey with the 0.68m Schmidt on November 16.20.
[CBET 4580, MPEC 2018-X14, 2018 December 1] It had been posted on the PCCP as ZW01220.
The object is at perihelion at 1.4 au in 2019 May and has a period of around 100 years.
No cometary activity was confirmed, so it was given a cometary style A/ designation.
On December 15 MPEC 2018-X136 and CBET 4582 reported that a coma had been detected in images taken with the CFHT on
December 8, so it was then given a C/ designation.
2018 W2 (Africano)
Brian Africano discovered a comet of 18th magnitude in Mt Lemmon Survey images taken with the
1.5m reflector on November 27.53. It was discovered at almost the same time by
Hannes Groeller in images taken by the Catalina Sky Survey with the 0.68m
Schmidt on November 27.51, but his report arrived after the one from Mt Lemmon.
The object was placed on the PCCP as ZW8B74D.
[CBET 4580, MPEC 2018-X23, 2018 December 3] The comet was at perihelion at 1.5 au in 2019 September.
It brightened quite rapidly and reached 9th magnitude in late September. It is fading rapidly and has moved south so is
no longer visible from the UK.
A/2018 WB1 [Mt Lemmon]
The Mt Lemmon Survey discovered an asteroid in images taken with the 1.5m
reflector on 2018 November 19.16. An orbit was published on MPEC 2018-W56 [2018 November 27]
An object was discovered by PanSTARRS 1 on 2019 August 9.5 and posted on the PCCP as P10Qxrp. This was then
linked to the previously discovered object. [MPEC 2019-P97, 2019 August 13]
There is currently no evidence for cometary activity.
The asteroid is classified as a Centaur by JPL.
It was at perihelion at 2.2 au in 2018 November and has a retrograde orbit with a period of 20 years. It has a
Jupiter MOID of 0.24 au.
A/2018 W3 [A/DECam]
The orbit for this object was published in MPEC 2022-Q17 [2022 August 18]. The discovery observation is
credited to Cerro Tololo-DECam using the 4.0-m f/2.7 CTIO reflector on November 29.33, when it was 21st
magnitude. DECam also imaged it in 2018 February. THe vast majority of observations come from TESS,
between 2020 July and 2021 June. Sam Deen found the object in images taken at Cerro Paranal with the
2.65-m Ritchey-Chretien on 2019 December 19 and 22. No details are given on the MPEC. The asteroid is
in a near parabolic orbit with perihelion at 4.3 au in 2021 April. It should still be around 19th magnitude.
2018 X1 (376P/LONEOS)
Erwin Schwab reported the recovery of 2005 GF8 in
images taken with the 1.0m reflector at the European Space Agency's Optical
Ground Station at Teneriffe on December 4.25. The correction to the prediction by B. G.
Marsden on MPC 54823 is delta-T = -1.4 days. [CBET 4581, MPEC 2018-X49, 2018 December 6]
2018 X2 (Fitzsimmons)
Alan Fitzsimmons (a noted British comet enthusiast and professional astronomer) discovered a 19th magnitude comet in images taken with the ATLAS
(Asteroid Terrestrial-impact Last Alert System) 0.5m Schmidt at Haleakala on December 8.47. It had been posted on the PCCP as A10azqg.
[CBET 4583, MPEC 2018-X135, 2018 December 15]. The comet is at perihelion at 2.1 au in 2019 July.
2018 X3 (PanSTARRS)
A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m
Ritchey-Chretien on December 12.46. There were pre-discovery images from PanSTARRS 2 taken in October and November.
It had been posted on the PCCP as P10Ksrl.
[CBET 4584, MPEC 2018-Y23, 2018 December 17] The comet was near perihelion at 2.7 au and has a period of
about 44 years. JPL classify it as a Halley-type comet.
2018 Y1 (Iwamoto)
Masayuki Iwamoto (Awa, Tokushima, Japan) discovered another comet in images taken on December 18.84 with a 10-cm
f/4.0 Pentax SDUF II telephoto lens and a Canon EOS 6D camera. The comet was around 13th magnitude with a well condensed coma.
It had been posted on the PCCP as IF032. [CBET 4588, MPEC 2018-Y52, 2018 December 20]
The preliminary
orbit suggests that the comet might have been discoverable by a southern hemisphere survey telescope earlier in the year.
It then passed through solar conjunction and has just emerged into the morning sky. The comet
was approaching
perihelion in early February at 1.3 au and passed 0.3 au from the Earth on
February 12. Kevin Hills and Nick James contributed astrometry. It
became visible from the UK in mid January and was a large and diffuse object.
2018 Y2 (P/Africano)
Brian Africano discovered a comet of 19th magnitude in Mt Lemmon Survey images
taken with the 1.5m reflector on December 31.29. There were pre-discovery images
from December 10 and 17. The object was placed on the PCCP as ZYAF0D0. [CBET
4590, MPEC 2019-A20, 2019 January 2] The comet was at perihelion in 2019 January at 3.9 au and has a period
of around 20 years.
2018 YW [A/PanSTARRS]
A 22nd magnitude asteroid was discovered in images taken with the Pan-STARRS 1 1.8m Ritchey-Chretien on December 17.63
by the PanSTARRS team.
It is a Apollo asteroid with a period of 7.5 years and a perihelion distance of 0.9 au
in 2019 February. It is an NEO with an Earth MOID of 0.18 au and it passes 0.33 au away on 2019 January 19. It has
been suggested that it may be an inactive comet.
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 used to give 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