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On images taken on Oct. 9, 2019 the Asteroid Terrestrial-Impact Last Alert System (ATLAS) discovered an asteroidal object in Canis Major, which showed cometary activity during the following days. Comet C/2019 T4 (ATLAS) displayed a 1.5" coma of total magnitude 19.0 and a 2" tail in p.a. 110°. It will pass perihelion on June 9, 2022 in the solar distance of 4.25 AU (CBET 4681). Despite the rather large perihelion distance it could become visible in amateur telescopes. Depending on the actual brightness development it could peak at magnitude 15.0 (n=3) or even 14.0 (n=4) in spring 2022. From mid-European locations it should be best visible between March and June 2022, moving northward from Hydra towards Crater and Virgo.
Pre-perihelion the comet showed an activity above average, whereas post-perihelion the activity was average, as is shown by 383 observations from 40 observers (until the start of May 2024). The brightness development is well represented by the following formulae pre-perihelion: m = 0.4 mag + 5×log D + 14.2×log r post-perihelion: m = 4.3 mag + 5×log D + 8.0×log r This yields a maximum brightness of 11.9 mag in mid-April 2022. Until the opening of July 2023 the comet had faded to 13.5 mag, until end of April 2024 to 15.0 mag. Between April 2021 and May 2022 the coma diameter increased from 0.5' (90,000 km) to almost 2' (300,000 km). Between fall 2022 and summer 2023 the apparent diameter was constant at 1.5', as was the absolute coma diameter (325,000 km). In October 2023 it was estimated as 1.1' (290,000 km), in April 2024 as 0.5' (150,000 km). In 2021/22 the coma was significantly condensed (DC 5), but got more diffuse thereafter (spring 2023: DC 2-3). A tail of up to 6' (5 mio. km) length, pointing in southwesterly directions, could be observed between December 2021 and October 2023.
Total Brightness and Coma Diameter (standard time scale)
Total Brightness and Coma Diameter (compressed time scale)
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An asteroidal object of magnitude 21, which was already discovered in the constellation Lyra on Oct. 22, 2019 by the PanSTARRS project, showed a near-parabolic orbit. Therefore attention was paid to the appearance of cometary activity. In 2020 hints of such activity had been reported, but not prior to early April 2021 comet C/2019 U5 (PANSTARRS) clearly showed cometary morphology. Observers reported a 15x10", east-west elongated coma with a total magnitude of 17.2. The comet will reach its mid-range perihelion not until March 29, 2023, when it will get as close as 3.62 AU to the Sun (CBET 4953). Assuming a "new" comet it may get as bright as magnitude 13 at that time. It should be brighter than 16 mag between early 2022 and the end of 2024. During this period it will move through the constellations Hercules, Bootes, Canes Venatici, Coma Berenice, Virgo, Leo, Sextant, Hydra, Antlia, Vela and Puppis. From mid-European latitudes it may remain observable until the end of May 2023.
Based on 336 observations from 40 observers (until start of May 2024) the brightness development can be well described by the formulae pre-perihelion: m = 3.6 mag + 5×log D + 11.5×log r. post-perihelion: m = 4.9 mag + 5×log D + 9.5×log r. The comet peaked at magnitude 12.1 during the second half of March 2023. After the conjunction with the Sun in 2023 it was of magnitude 14.5 in December and of magnitude 15.0 in April 2024. The apparent coma diameter increased from 0.7' at the start of the apparition to the maximum of 2.0' during the second half of March 2023, whereas the absolute diameter expanded from 150,000 km to 225,000 km. In winter 2023/24 and in spring 2024 it measured only 0.6' (120,000 km). Whereas the coma was significantly condensed (DC 4-5) during the first half of 2022 it had grown more diffuse (DC 3) at the opening of 2023. CCD-observers detected a tail up to 9' (9 Mio. km) long, constantly directed towards Northeast.
Total Brightness and Coma Diameter (standard time scale)
Total Brightness and Coma Diameter (compressed time scale)
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On images taken on May 6, 2020 the PanSTARRS project discovered a comet of magnitude 20.2 in the constellation Draco. Comet C/2020 K1 (PANSTARRS) showed a miniscule coma of diameter about 1" and a 2" tail pointing towards Northeast. The comet will pass perihelion on May 9, 2023 at the solar distance of 3.07 AU, expected to reach 13 mag around this date (CBET 4779, MPECs). However, it will be positioned in the far-southern sky during the most interesting months. It should be brighter than 16 mag between April 2022 (located in the southern part of Hercules) and April 2024 (constellation Pictor). At mid-European locations the comet will disappear above the southwestern evening horizon already at the end of October 2022. At this time it will be positioned in the southern parts of Ophiuchus, expected to be of magnitude 15.
Based on 267 observations from 35 observers the comet showed a break in the brightness development pre-perihelion. Until 280 days prior to perihelion (Aug. 1, 2022) the activity was above average, but during the next 280 days the activity was zero! Post-perihelion the comet faded steadily and in an average manner. The appropriate brightness parameters are t < -280d: m0 = 2.4 mag / n = 5.3 -280d < t < 0d: m0 = 10.4 mag / n = 0 t > 0d: m0 = 5.6 mag / n = 4 Thus the comet peaked at 12.4 mag at the opening of June 2023. Until mid-September 2023 the comet had faded to 14.0 mag, until end of January 2024 to 14.5. Between April and June 2022 the coma diameter increased from 0.5' (110,000 km) to 1.4' (200,000 km). These values was hold until August. In fall 2022 the diameter decreased to 1.1', which corresponds with a constant absolute coma diameter of 200,000 km. In spring 2023 the coma measured 1.3', corresponding to 160,000 km. It had shrunk to 0.6' by mid-September 2023 and to 0.5' (100,000 km in both cases) by January 2024. Surprisingly the degree of condensation decreased from the start of the apparition to fall 2022 from DC 5 to DC 3, where it remains since then. Reports of tail observations had been very rare.
Total Brightness and Coma Diameter (standard time scale)
Total Brightness and Coma Diameter (compressed time scale)
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An asteroidal object of magntiude 19, which was already discovered on Apr. 21, 2021 by the ATLAS-Team in the constellation Canis Major showed faint cometary signatures during follow-up observations. Until October 2021 additional observations clearly confirmed the cometary nature. Comet C/2021 G2 (ATLAS) will pass perihelion on Sep. 9, 2024 at the solar distance of 4.98 AU, expected to reach magnitude 15.0 in spring 2024 and 2025 (CBET 4988/5057). It should be brighter than 16 mag between November 2023 and August 2025. During this period it moves through the constellations Hydra, Corvus, Virgo and Libra. From mid-European latitudes it will appear in December 2024 above the southeastern morning horizon, and will change into the evening sky in May 2025.
At the start of May 2024 116 observations from 8 observers can be used for a preliminary analysis. However, one observer is disproportionately represented in the current database, which makes the statements somewhat uncertain. So far the comet has developed according to the brightness parameters
m0 = 2.8 mag / n = 4.5.
Thus it should have peaked at 13.9 mag at the opening of May 2024 and should reach a secondary maximum of 14.1 mag in mid-April 2025. In December 2023 the coma diameter measured only 0.5' (125,000 km), but was estimated at 1.2' (225,000 km) at the beginning of May 2024. During the same period the degree of condensation appears to have increased slightly from DC 4 to DC 5. Since the start of the apparition a tail, up to 2' (3 mio. km) long, was observed, constantly pointing towards WSW.
Total Brightness and Coma Diameter
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On Dec. 2, 2021 Alain Maury and Georges Attard discovered a slightly diffuse 19 mag object near the border of the consteallations Puppis/Pyxis. During the following weeks and months several observers reported cometary morphology. Early May 2022 comet C/2021 X1 (Maury-Attard) displayed a 9" coma of total magnitude 17.2 and a 10" tail in p.a. 100°. The comet will pass perihelion on May 27, 2023 in the solar distance of 3.23 AU (CBET 5119) and should peak at a maximum brightness of 14.5 mag in late summer 2023 (after reaching 15.0 mag in Dec. 2022). It should be brighter than 16 mag between October 2022 and end of 2023. During this interval it will move through the constellations Canis Mayor, Lepus, Eridanus, Cetus and Pisces towards the border of Pegasus/Aquarius. It will be near opposition in Pisces, well-placed for mid-European locations.
For the analysis 98 observations from 19 observers could be used. The observations can be represented rather well by the brightness parameters
m0 = 8.3 mag / n = 3.
Thus the comet reached a first maximum of 14.7 mag during the second half of December 2022 and peaked at 14.3 mag in mid-September 2023. The very last observations seem to hint towards a rapid decline in activity. The diameter of the medium-condensed (DC 4) coma increased until September 2023 from 0.4' (60,000 km) to 1.2' (130,000 km), but decreased to 0.7' (90,000 km) until November 2023. A tail could be detected by CCD observers during the entire apparition. It reached a length of 15' in fall 2023, which would correspond to an absolute length of about 30 mio km. This is quite implausible, so it is much saver to assume a significant curvature of the tail.
Total Brightness and Coma Diameter
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An 18 mag asteroidal object, discovered by the ATLAS team on Mar. 7, 2022 in the constellation Antlia showed cometary morphology in the course of follow-up observations. Comet C/2022 E2 (ATLAS) showed a highly condensed 7" coma of total magnitude 18.0, but no tail. The comet will pass perihelion on Sep. 15, 2024 at the solar distance of 3.67 AU, expected to reach magnitude 13 (CBET 5109). It should be brighter than 16 mag between March 2021 and January 2026. During this interval it will move through the constellations Hydra, Cancer, Gemini, Lynx (perihelion), Camelopardalis, Cassiopeia, Lacerta and Pegasus. Thus it will be well-placed for mid-European locations during the most interesting months.
Up to the start of May 2024 the comet has shown a fairly steady brightness development, as demonstrated by 191 observations from 35 observers. This can be represented quite well with the parameters
m0 = 5.4 mag / n = 3.5.
This results in a first maximum of 13.3 mag in mid-February 2024 and a maximum brightness of 12.8 mag at the end of November 2024. The coma diameter measured 0.4' (90,000 - 100,000 km) for many months, but starting in October 2023 it increased noticeably, reaching 1.3' (200,000 km) at the beginning of March 2024. So far the coma has shown a constant degree of condensation of DC 4-5. Since the start of the apparition a tail of up to 3' (3 mio. km) length can be detected. The orientation of the tail initially turned from ESE to SSE, only to turn back to SE by May 2024.
Total Brightness and Coma Diameter
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On June 10, 2022 the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) - team discovered a comet near the border of the constellations Cygnus/Lyra. Comet C/2022 L2 (ATLAS) showed a strongly condensed 8" coma of total magnitude 18.5m, but no tail. The comet will pass perihelion on Mar. 17, 2024 at the solar distance of 2.76 AU, expected to reach magnitude 13.0 (CBET 5136). Between May 2023 and January 2025 it should be brighter than 16 mag. During this period it will move through the constellations Hercules, Serpens, Libra, northern Centaurus (maximum brightness), Hydra (opposition loop), Antlia, Vela and Puppis. From mid-European locations the comet should be observable until the opening of October 2023 (then at magnitude 15.5) in the midnight and evening sky, and then again between December 2023 and February 2024 (then at magnitude 13.5) in the morning sky. In April 2024 its altitude is below 10° and in early May it will disappear completely.
An unusual brightness development of this comet is indicated by 104 observations from 13 observers (mostly obtained via CCD). This can only be meaningfully described by a very small activity factor, whereby the parameters
m0 = 12.8 mag / n = 0
are the most plausible. Thus the comet should have reached its maximum brightness of about 14.0 mag at the beginning of April 2024. The coma diameter was estimated at 0.4' (55,000 km) over a longer period, reaching a maximum of 0.8' (75,000 km) at the end of April 2024. The degree of condensation was DC 3-4 most of the time, but may have risen to DC 5 in April 2024. Since the start of the apparition a short tail has been observed, pointing towards ENE for most of the time, which reached a maximum length of 6' (2 mio. km).
Total Brightness and Coma Diameter
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On July 4, 2022 the PANSTARRS team discovered a comet of magnitude 20 in the constellation Sagittarius. Comet C/2022 N2 (PANSTARRS) showed a condensed 2" coma and a 3" tail in p.a. 260°. It will pass perihelion at the solar distance of 3.84 AU on Aug. 3, 2025, expected to peak at magnitude 14.5 in October/November 2025 (CBET 5148). At discovery it was still at a distance of 9.5 AU from the Sun! Between April 2025 and February 2026 it should be brighter than 16 mag. During this period it moves from central Pisces northeastward to the region near the border of the constellations Aries/Taurus. Thus the observing conditions are optimal for mid-European locations during the time the comet is brightest.
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On Feb. 1, 2023 the ATLAS team discovered a 19th magnitude asteroidal object near the border of the constellations Centaurus/Vela, which showed cometary morphology in follow-up observations. Comet C/2023 C2 (ATLAS) exhibited a 9" coma of total magnitude 19.0 with a central condensation. The comet will pass perihelion at the solar distance of 2.37 AU on Nov. 16, 2024 and should reach a maximum brightness of 13.5-14.0 mag in August 2024 (CBET 5240). It should be brighter than 16 mag between March 2024 and July 2025. During this period it moves through the constellations Apus, Triangulum Australis, Norma (maximum brightness), Scorpius, Sagittarius (perihelion), Capricornus, Aquarius, Pegasus, Andromeda and Cassiopeia. From central European locations the comet can be sighted just above the southwestern evening horizon between November 2024 (14.0 mag) and January 2025 (14.5 mag) during the first period. It then reappears over the eastern morning horizon in March 2025 (15.0 mag), slowly gaining altitude during the following months, thereby steadily fading.
According to the still small number of observations (until the start of May 2024) so far the comet has developed according to the predictions. Based on only 24 observations from 4 observers (with one observer overrepresented) the brightness develops according to the parameters
m0 = 9.0 mag / n = 3,
yielding a maximum brightness of 13.7 mag in August 2024. The coma diameter was estimated at 0.5' in April 2024.
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The PANSTARRS team discovered another comet on Sep. 7, 2023 near the border of the constellations Pisces/Andromeda. Comet C/2023 R1 (PANSTARRS) showed a 1.5" coma of total magnitude 19.5. It will not pass its mid-distance perihelion at the solar distance of 3.57 AU until Apr. 14, 2026 (then expected to be of magnitude 15) and should peak at 14 mag in June 2026 (CBET 5293). It should be brighter than 16 mag between July 2025 and October 2026, when it will move through the constellations Pegasus, Vulpecula, Sagitta, Aquila (perihelion), Scutum, Serpens Cauda, Ophiuchus, (maximum brightness), Serpens Caput and Libra. From Central European locations it can be followed until September 2026 - with the exception of the period from mid-December 2025 to the end of January 2026.
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Just three days later, on Sep. 10, 2023, the PANSTARRS team succeeded in discovering a comet near the border of the constellations Cetus/Eridanus. Comet C/2023 R2 (PANSTARRS) presented a highly condensed 8" coma of total magnitude 20.0 and a 5" tail in p.a. 150°. The comet will pass perihelion at the solar distance of 0.91 AU on Aug. 12, 2024, expected to peak at magnitude 13.0 during those days (CBET 5301). It should be brighter than 16 mag between mid-May and end of October 2024. During this period it will move through the constellations Taurus, Orion, Monoceros, Canis Minor, Cancer/Hydra, Sextans (perihelion), Leo, Virgo and Serpens Caput. Unfortunately, the comet will experience elongations of less than 24° during this period, so will be a challenging object.
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On their images taken on Nov. 5, 2023 with two 28cm-SC and CMOS cameras at the Hakos Astrofarm, the Spanish amateur Jordi Camarasa and the Swedish amateur Grzegorz Duszanowicz discovered a comet of magnitude 18.5, showing a tail, in the constellation Horologium. Follow-up observations of comet C/2023 V4 (Camarasa-Duszanowicz) showed a strongly condensed, 8" coma of total magnitude 18.5 and a 0.3' long curved tail in p.a. 340°. The comet will pass perihelion at the solar distance of 1.12 AU on May 30, 2024, but will then unfortunately be on the opposite side of the sun relative to Earth and therefore difficult to observe. The comet is expected to peak at magnitude 14.0-14.5 in June 2024 (CBET 5315). It should be brighter than 16 mag between March and August 2024. During this period it will move through the constellations Cetus, Aries, Perseus, Auriga, Lynx, Ursa Major and Canes Venatici. For Central European locations it is positioned very low above the western to northwestern evening horizon until mid-June. It then begins to rise, reaching a maximum altitude of 30° at the end of July.
Based on only one dozen observations (at the start of May 2024) it seems that the comet is brighter and shows a faster development, according to the still rather uncertain parameters
m0 = 8.5 mag / n = 6
During the first week of March 2024 the brightness was estimated at about 13.5 mag, the coma diameter at about 0.7'. If the comet should continue to follow these brightness parameters, it will peak at magnitude 11 mag at the opening of June 2024.
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On Feb. 14, 2024, an asteroidal object with an estimated total magnitude of 16.5-17.0 was discovered in the constellation Ara in the course of the ATLAS project. During the following days it was recognized as a comet. Comet C/2024 C4 (ATLAS) showed a highly condensed, 25" coma of total magnitude 15.8, and a 30" tail in p.a. 227°. The comet had already passed perihelion at a solar distance of 1.47 AU on Jan. 30, 2024 when it should have been of magnitude 16.0 (CBET 5354, various MPECs). Between the start of February and the end of April the comet should have been brighter than 16 mag, with peak brightness expected at 15.2 mag at the start of April, because the comet will still be approaching Earth until mid-April. During this period it will move in a northerly direction through the constellations Ara, Scorpius, Ophiuchus and Serpens. For Central European locations it will appear above the southern morning horizon during the first week of March, thereafter rapidly gaining altitude during the following weeks, thereby fading slowly.
Based on only 10 observations the brightness parameters can be very roughly determined as
m0 = 11.5 mag / n = 6.
The comet appears to have reached a maximum brightness of about 14.5 mag in March 2024, thereafter fading to 16.5 mag by the beginning of May. The extremely diffuse coma reached a diameter of about 0.8'.
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On Mar. 3, 2024, Kacper Wierzchos discovered a comet with the 1.5m reflector on Mt. Lemmon. The comet, positioned in the constellation Draco, had a highly condensed, 4" coma of total magnitude 20.0-20.5 and a 6" tail in p.a. 320°. At a distance of 8 AU at discovery comet C/2024 E1 (Wierzchos) will not pass perihelion at a solar distance of 0.56 AU until Jan. 21, 2026, then predicted to peak around magnitude 7 (CBET 5364). However, at this time the comet will be on the opposite side of the Sun relative to Earth, thus being positioned close to the Sun, making observations very difficult. It should be brighter than 16 mag between June 2025 and July 2026. During this period it will move through the constellations Draco, Hercules, Corona Borealis, Hercules, Ophiuchus, Serpens, Sagittarius (perihelion), Microscopium, Grus, Phoenix, Sculptor, Cetus, Eridanus, Taurus and Gemini. From Central European locations it can be seen in the evening sky until the end of November 2025 (then only 11 mag) and then again between the end of February (about 8 mag) and mid-May 2026 (about 13 mag).
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An asteroidal object of magnitude 19, discovered by the ATLAS team on Apr. 5, 2024 near the borders of the constellations Apus/Pavo/Octans showed a cometary morphology in the course of detailed observations. Comet C/2024 G3 (ATLAS) showed a significantly condensed coma of diameter approximately 5" and of total magnitude 18.5 and a 7" tail in p.a. 300°. It will pass perihelion at the solar distance of only 0.09 AU on Jan. 13, 2025, when it should peak at magnitude 2 if it follows a standard development (CBET 5384). However, its absolute magnitude appears to be well below the Bortle limit, meaning that it could possibly disintegrate while approaching the Sun. In addition, the comet will stay north of the ecliptic plane for only seven days, as its parabola is oriented almost perpendicular to the ecliptic and it approaches the Sun from the South and will disappear towards the South thereafter. In the case it will not disintegrate the comet should be brighter than 16 mag between mid-August 2024 and mid-June 2025. During this period it will move through the constellations Centaurus, Lupus, Scorpius, Sagittarius (perihelion), Capricornus, Piscis Austrinus, Grus, Phoenix, Eridanus and Horologium. The comet cannot be observed from Central European locations during this period.
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On Jan. 3 the first comet of 2024 was discovered by the ATLAS project. The comet was located near the borders of the constellations Volans/Pictor/Carina, showing an 8" coma of total magnitude 18.5 and a 5" tail in p.a. 300°. Comet C/2024 A1 (ATLAS) will pass perihelion at the solar distance of 3.88 AU on June 13, 2025, but will then be positioned very close to the Sun (CBET 5333). It should peak at 15.5 mag in February 2025. The comet should be brighter than 16 mag between December 2024 and April 2025 and again between October 2025 and January 2026. During the first period it will move through the constellations of Puppis, Canis Major and Monoceros, during the second period through the eastern part of the constellation Lynx. From Central European locations it will be observable at moderate altitudes in the morning sky at first during the first period, but will move into the evening sky (at higher altitudes) during the course of this first visibility. During the second visibility it will be at higher altitudes in the morning sky.
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Comet 32P/Comas Sola (P=9.73a) will pass perihelion at the solar distance of 2.02 AU on Apr. 20, 2024, but will come closest to Earth on Nov. 30, 2023. As a result the comet is expected to peak at magnitude 14.0 at the beginning of February 2024. The comet should be brighter than 16 mag between October 2023 and August 2024. During this period it will move through the constellations Aries, Taurus, Auriga, Gemini, Cancer and Leo. From central European locations the comet will appear in the night sky at first, but will change to the evening sky in December 2023 and will disappear above the Northwestern horizon in February 2024.
Despite a maximum brightness of only 14.0 mag in the second half of January 2024, 75 observations from 24 observers can be used for the analysis, most of which are CCD observations. The brightness development can be described well with the parameters
m0 = 7.3 mag / n = 6.7.
The coma diameter increased from 0.4' (30,000 km) at the beginning of the apparition to the maximum of 1.3' (100,000 km) in January/February 2024. The number of estimates of the degree of condensation is very small, but they seem to indicate a decrease from DC 7 to DC 3 during the apparition. A tail of up to 2-3' (1.25 mill. km) length was detected throughout the apparition. It was directed towards the WSW until the end of November, thereafter towards the East.
Total Brightness and Coma Diameter
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Comet 207P/NEAT (P=7.65a), which approached Earth to within 0.22 AU on Mar. 5, 2024, was observed between the opening of the year and the start of April 2024. Based on 48 CCD observations by 11 observers the brightness development can be well represented by the parameters
m0 = 17.0 mag / n = 2,
resulting in a maximum brightness of 13.8 mag at the beginning of March 2024. The apparent coma diameter measured 0.4' at the start of the apparition, reached a maximum of 1.1' at the end of February 2024 and shrank to 0.8' by the end of the apparition. In consequence the absolute coma diameter measured only 8,000 km at the start of the apparition, but it quickly increased to 18,000 km afterwards (this value remained constant until the end of the apparition). The coma was moderately condensed (DC 4).
Total Brightness and Coma Diameter
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Based on only 26 CCD observations by 10 observers comet 226P/Pigott-LINEAR-Kowalski (P=7.31a) reached a maximum brightness of about 15.0 mag in mid-January 2024, thereby showing a maximum coma diameter of 0.8'. The brightness estimates cannot be represented by a standard formula, but indicate a further increase in activity until at least 70 days after perihelion, which means that the apparent brightness changed only slightly after perihelion. The comet will be too close to the Sun for further observations in the coming months.
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Comet 227P/CATALINA-LINEAR (P=6.37a) reached a maximum brightness of 15.0 mag at the end of February 2024, as 27 CCD observations by 11 observers show. The brightness parameters can only be determined with greater uncertainty, as the variance in the solar distance was very small. The most plausible values are
m0 ≈ 17.0m / n ≈ 2.
The diameter of the coma only increased from 0.3' (10,000 km) at the beginning of the apparition to 0.6' (25,000 km) at the time of perihelion, but it appears to have been noticeably condensed. A constantly SE-oriented tail of up to 1' (100,000 km) length was observed around perihelion.
Total Brightness and Coma Diameter
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Comet 473P/NEAT (P=22.50a), which passed perihelion at a solar distance of 1.40 AU on Feb. 26, 2024, reached magnitude 12.5 at the end of February 2024! However, only 15 observations from 6 observers can be used for a very rough analysis. Despite this tiny sample, a different brightness development pre- and post-perihelion seems to be significant. The observations can be represented with the following parameters:
pre-perihelion: m0 ≈ 4.0m / n ≈ 20
post-perihelion: m0 ≈ 7.5m / n ≈ 10
The coma diameter was about 2-3'. A tail was not published. The comet should become fainter than 16 mag by the end of May.
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Comet P/2011 NO1 (Elenin) was rediscovered on Nov. 18, 2023, but was initially confused to be a minor planet, for which was given the designation 2023 WM26. Maik Meyer was the first to recognize that this comet had indeed been rediscovered, thus it later got the permanent designation 479P/Elenin. On Dec. 23 the comet exhibited a highly condensed, 5" coma with a total magnitude of 19.5. The comet will pass perihelion on May 5, 2024 at a distance of 1.24 AU, expected to reach magnitude 14 (CBET 5340). It should be brighter than 16 mag between March and June. During this period, it will pass through the constellations Canis Minor, Monoceros and Hydra (south of Corvus). From Central European locations it can be seen in the evening sky until the beginning of May.
The observations of this comet, published up to the start of May 2024, are very inconsistent. A total of 56 observations (mostly by CCD) by 12 observers show a dichotomy in the brightness estimates, which systematically differ by about 2.5 mag. Thus I have to present two solutions, whereby the hope remains that additional observations will show the more plausible development. In any case, the comet has a high activity factor, which is about n=20 for both solutions. The absolute magnitudes are m0=10.0 mag (solution 1) and m0=12.5 mag (solution 2). This means that the comet should have peaked at 11.0 mag or 13.5 mag at the beginning of May 2024. The coma diameter has so far increased from 0.6' (17,000 km) to 1.3' (35,000 km), whereby the coma is moderately condensed (DC 3). A tail has not yet been observed.
Total Brightness and Coma Diameter
Andreas Kammerer
