By Paul Roggemans, Denis Vida, Damir Šegon, James M. Scott, Jeff Wood

Abstract: The Global Meteor Network recorded an outburst from the A Carinids (842#CRN) during October 13 – 14, 2025. In total, 171 meteors belonging to this meteor shower were observed between 196.0° < λʘ < 204.0° from a radiant at R.A. = 100.9° and Decl.= –55.4°, with a geocentric velocity of 31.5 km/s. In 2023 and 2024, only 15 and 29 possible CRN-meteors were recorded. This case study confirms the existence of this meteor shower with a new solution added to the IAU-MDC working list of meteor showers.

 

1 Introduction

On 13–14 October 2025 some unusually strong activity was spotted near the South Pole (Figure 1). The radiant source was identified as the A Carinids (842#CRN), first reported by Jenniskens (2018) from CAMS southern hemisphere low-light video observations. The night of October 13 on 14, 2020 displayed an outburst (Jenniskens, 2020). Because of enhanced activity observed in 2014 and 2019–2020, with weak activity in between, the shower has been listed as an episodic shower (Jenniskens, 2023). The 2025 outburst confirms this periodic nature. Figure 1 shows the position of the A Carinids radiant which is close to the South Pole and close to the October epsilon-Carinids (OEC#1172).

Figure 1 – Radiant density map (sinusoidal projection) with 1812 radiants obtained by the Global Meteor Network during 13–14 October, 2025. The position of the A Carinids in Sun-centered geocentric ecliptic coordinates is marked with a yellow arrow.

 

2 Shower classification based on radiants

The GMN shower association criteria assume that meteors within 1° in solar longitude, within 4.9° in radiant in this case, and within 10% in geocentric velocity of a shower reference location are members of that shower. Further details about the shower association are explained in Moorhead et al. (2020). Using these meteor shower selection criteria, 171 orbits have been identified as A Carinids.

 

Figure 2 – Dispersion median offset on the radiant position.

 

Figure 3 – The radiant distribution during the solar-longitude interval 196° – 204° in equatorial coordinates.

 

Figure 4 – The radiant drift.

 

Figure 5 – The uncorrected number of shower meteors recorded per degree in solar longitude.

 

Figure 6 – All non-shower meteor radiants in geocentric equatorial coordinates during the shower activity. The pale diamonds represent the shower radiants plots, error bars represent two sigma values in both coordinates.

 

Figure 7 – The reverse of Figure 6, now the shower meteors are shown as circles and the non shower meteors as grayed out diamonds.

 

The shower was independently observed in 2025 by 186 cameras in Australia, Brazil, Chile, New Zealand and South Africa. The shower had a median geocentric radiant with coordinates R.A. = 100.9°, Decl. = –55.4°, within a circle with a standard deviation of ±2.0° (equinox J2000.0). The radiant drift in R.A. is +0.46° on the sky per degree of solar longitude and +0.27° in Dec., both referenced to λʘ = 201.0° (Figures 3 and 4). The uncorrected raw numbers of shower meteors per degree in solar longitude indicate that most CRN-meteors were recorded around λʘ = 201.0° (Figure 5). Figures 6 and 7 show that the A Carinids appeared on top of the sporadic background noise. The median Sun-centered ecliptic coordinates were λ – λʘ = 279.0°, β = –77.5° (Figure 8). The geocentric velocity was 31.5 ± 0.1 km/s. The shower parameters as obtained by the GMN method are listed in Table 1.

 

Figure 8 – The radiant distribution during the solar-longitude interval 196° – 204° in Sun centered geocentric ecliptic coordinates.

 

Figure 9 – Rayleigh distribution fit and Drummond DD criterion cutoff.

 

3  Shower classification based on orbits

Meteor shower identification strongly depends upon the methodology used to select candidate shower members. The sporadic background is almost everywhere present and risks contamination of selections of shower candidates. In order to double check GMN meteor shower detections, another method based on orbit similarity criteria is used. This procedure serves to make sure that no spurious radiant concentrations are mistaken as meteor showers.

A reference orbit is required to start an iterative procedure to approach a mean orbit, which is the most representative orbit for the meteor shower as a whole, removing outliers and sporadic orbits (Roggemans et al., 2019). Three different discrimination criteria are combined in order to have only those orbits which fit the different criteria thresholds. The D-criteria that we use are these of Southworth and Hawkins (1963), Drummond (1981) and Jopek (1993) combined. Instead of using a single cutoff value for the threshold of the D-criteria, these values are considered in different classes with different thresholds of similarity. Depending upon the dispersion and the type of orbits, the most appropriate threshold of similarity is selected to locate the best fitting mean orbit as the result of an iterative procedure.

The Rayleigh distribution fit indicates that a very small cutoff value is required with DD < 0.035 (Figure 9). The use of D-criteria requires caution as the threshold values differ for different types of orbits. Because of the very small cutoff of the threshold values of the D-criteria, only three classes were plotted:

  • Medium: DSH < 0.1 & DD < 0.04 & DJ < 0.1;
  • High: DSH < 0.075 & DD < 0.03 & DJ < 0.075.
  • Very high: DSH < 0.05 & DD < 0.02 & DJ < 0.05.

This method resulted in a mean orbit with 101 related orbits that fit within the similarity thresholds with DSH < 0.075, DD < 0.03 and DJ < 0.075, recorded October 10 – 18, 2025. The plot of the radiant positions in equatorial coordinates, color-coded for different D-criteria thresholds, has its radiant at 99.7° in Right Ascension and –55.1° in declination (Figure 10). A slightly more tolerant threshold of the D-criteria with DSH < 0.10, DD < 0.04 and DJ < 0.1 results in 126 orbits that fit these threshold values, but with a risk of including contamination with sporadics. Both solutions are mentioned in Table 1.

Figure 10 – The radiant distribution during the solar-longitude interval 196° – 207° in equatorial coordinates in 2025, color-coded for different threshold values of the DD orbit similarity criterion.

 

The dense concentration just left below from the CRN radiants are the October epsilon-Carinids (OEC#1172), an annual shower. Most likely both meteoroid streams are components with a common origin. Near the upper-right corner another concentration of radiants is visible. These are the Caelids (CAE#837).

Looking at the Sun-centered geocentric ecliptic coordinates (Figure 11), the radiant appears stretched in Sun centered longitude because of its position close to the ecliptic South Pole. The dense concentration just left from the CRN radiant is again the OEC radiant. A case study about the October epsilon-Carinids has been published in another report (Roggemans et al., 2026).

Figure 11 – The radiant distribution during the solar-longitude interval 196° – 207° in Sun-centered geocentric ecliptic coordinates, color-coded for different threshold values of the DD orbit similarity criterion.

Figure 12 – The percentage of OEC meteors relative to the total number of meteors recorded by cameras at the Southern Hemisphere. Orange is the result for the GMN shower classification, blue for the D-criteria threshold method.

If we look at the ratio CRN-meteors to non-CRN-meteors recorded by GMN at the Southern Hemisphere (Figure 12) in 1.5°-time bins in solar longitude in steps of 0.25°, the moving average (dotted line), indicates that best rates occurred around λʘ = 200.0. However, the best rates may have occurred later and missed by the fact that most GMN cameras at the Southern Hemisphere are installed in Australia and New Zealand with rather little or no coverage at other longitudes. A short duration peak like observed in 2020 at λʘ = 200.9° (Jenniskens, 2020) has not been recorded in 2025.

The results obtained from both shower association methods are in good agreement although both methods identified 116 meteors in common with different additional meteors in each sample. 55 CRN-meteors were identified based on the radiant method but not selected by the orbit method with DSH < 0.1 & DD < 0.04 & DJ < 0.1. Only ten orbits were identified as CRN-orbits but not identified by the radiant based method, six of these were recorded after λʘ = 204.0°.

The radiant classification method has searched only the 2025 GMN data as no significant activity was found in previous years. The orbit classification method applied on previous years found only 17 orbits in 2023 and 29 orbits in 2024 that fit the thresholds DSH < 0.075, DD < 0.03 and DJ < 0.075. This shows that there is a modest annual activity. The much higher activity recorded in 2025 cannot be explained by the expansion of the GMN camera network and definitely concerns an outburst.

4 Orbit and parent body

Looking at the diagram of inclination versus longitude of perihelion, we can see a dense concentration (Figure 13).  The concentration on the lefthand side of the CRN-points are the October epsilon-Carinids and the concentration near the upper-left are the October 6-Draconids (OSD#745), which were active 10 days later than listed in the MDC working list of meteor showers.

Figure 13 – The diagram of the inclination i versus the longitude of perihelion Π color-coded for different classes of D criteria thresholds, for λʘ between 196° and 207°.

 

Figure 14 – The diagram of the eccentricity e versus the longitude of perihelion Π color-coded for different classes of D criteria thresholds, for λʘ between 196° and 207°.

 

The diagram in Figure 14 shows the distribution in longitude of perihelion and eccentricity. The concentration to the left from the CRN-meteors are the October epsilon-Carinids, and the concentration in the upper left consists mainly of the October Ursae Majorids (OCU#333).

Figure 15 shows the concentration in eccentricity and inclination. The cloud left of the CRN-meteors are meteors identified by the radiant method as OEC and some weaker activity sources.

 

Figure 15 – The diagram of the eccentricity e versus the inclination i color-coded for different classes of D criteria thresholds, for λʘ between 196° and 207°.

 

 

Table 1 – Comparing solutions derived by two different methods, GMN-method based on radiant positions and the orbit association method for DD < 0.04 and DD < 0.03 in 2025, 2023–2024 and 2023–2025.

2025 2023–2024 2023–2025
GMN DD < 0.04 DD < 0.03 DD < 0.04 DD < 0.03 DD < 0.04 DD < 0.03
λʘ (°) 201.0 200.4 200.3 198.4 198.2 200.1 200.1
λʘb (°) 196.0 196.2 197.0 196.2 196.2 196.2 196.2
λʘe (°) 204.0 205.3 205.2 204.7 201.8 205.7 204.8
αg (°) 100.9 99.7 99.7 98.0 97.9 99.0 98.7
δg (°) –55.4 –55.1 –55.1 –57.1 –57.2 –55.5 –55.5
Δαg (°) +0.46 +0.59 +0.49 +0.15 –0.20 +0.48 +0.44
Δδg (°) +0.27 +0.21 +0.19 +0.09 +0.08 +0.30 +0.22
vg (km/s) 31.5 31.4 31.4 30.5 30.4 31.1 31.2
Hb (km) 97.2 99.0 99.4 98.6 99.3 99.1 99.3
He (km) 83.1 83.2 83.2 81.8 81.4 83.2 83.0
Hp (km) 89.3 90.9 92.8 89.6 91.1 91.1 91.4
MagAp 0.0 0.0 –0.2 –0.4 –0.4 –0.1 –0.1
λg (°) 120.03 116.6 116.5 114.1 113.7 115.0 114.7
λg – λʘ (°) 279.03 276.7 275.6 275.9 274.8 275.4 274.7
βg (°) –77.53 –77.6 –77.5 –79.6 –79.8 –78.2 –78.2
a (A.U.) 3.018 2.96 2.97 3.14 3.18 3.00 3.01
q (A.U.) 0.996 0.996 0.996 0.997 0.997 0.996 0.996
e 0.670 0.664 0.665 0.682 0.686 0.669 0.669
i (°) 52.6 53.0 53.1 50.8 50.7 52.2 52.3
ω (°) 357.7 358.5 358.6 359.0 359.1 359.1 359.4
Ω (°) 20.4 20.6 20.6 18.6 18.5 20.1 20.0
Π (°) 18.12 19.1 19.2 17.6 17.6 19.1 19.4
Tj 2.41 2.44 2.43 2.38 2.36 2.43 2.42
N 171 126 101 78 47 210 132

 

Figure 16 – Comparing the mean orbits for the solutions for the A Carinids (blue) and the October epsilon-Carinids (red) based on the radiant identification, close-up at the inner Solar System. (Plotted with the Orbit visualization app provided by Pető Zsolt).

Figure 17 – 101 A Carinid orbits and their mean orbit as seen in the ecliptic plane. (Plotted with the Orbit visualization app provided by Pető Zsolt).

Figure 18 – 101 A Carinid orbits and their mean orbit as seen on top of the ecliptic plane. (Plotted with the Orbit visualization app provided by Pető Zsolt).

 

The Tisserand’s parameter relative to Jupiter, Tj (= 2.41) identifies the orbit as of a Jupiter Family Comet type orbit. Figure 16 compares the orbits of the A Carinids with the October epsilon-Carinids. The CRN meteoroid stream intersects the Earth orbit at its ascending node, hitting the planet from deep south of the ecliptic. The position of the descending node in the ecliptic plane is relatively close to the orbit of Jupiter. The CRN orbit is higher inclined to the ecliptic than the OEC orbit. Apart from the inclination, both streams differ mainly in longitude of perihelion with about 10°.

All 101 CRN-orbits recorded in 2025 that fit within DSH < 0.075, DD < 0.03 and DJ < 0.075 have been plotted in Figure 17 as seen in the ecliptic plane and in Figure 18 projected on the ecliptic plane. Despite the very strict D criteria cutoff values, the slightest uncertainty at the encounter with the Earth results in a large dispersion at the aphelia. In reality, the meteoroid stream will be more compact at its aphelion. The plotted dispersion is mainly due to measurement uncertainties.

A parent-body search of the top 10 results in candidates with a threshold for the Drummond DD criterion value lower than 0.16 (Table 2). Asteroid 2010 HY22 with DD < 0.086 looks like the most plausible candidate but orbit integrations are required to assess if there is a relationship. Jenniskens (2023) mentions 2009 SG18 as a possible, but uncertain, source, although this object does not appear in the top ten candidates found by GMN.

Table 2 – Top ten matches of a search for possible parent bodies with DD < 0.16

Name DD
2010 HY22 0.086
2010 LG64 0.107
2020 VM1 0.108
2022 RX3 0.119
2017 UZ42 0.13
2018 VG1 0.139
2019 WF1 0.14
(89830) 2002 CE 0.15
2019 UQ7 0.156
2016 XP23 0.158

 

5 Past years’ activity

The only video meteor observations known for the A Carinids are CAMS observations from 2019–2021 published by Jenniskens (2023). A search through historic visual meteor observations indicates that this shower has been observed in the past, but that it was not distinguished from the October epsilon-Carinids. The oldest records were by Cuno Hoffmeister (1948) with his observations in 1937 in Namibia, when some radiants were established from solar longitude 200.1° to 203.6° at R.A. 95°– 99° and decl. –53° to –55°. None of the later meteor observers in Australia, New Zealand, South Africa or South American observers from Bolivia, Brazil, Argentina, Columbia and Chile report any activity from this source. In Australia it was not detected by Maurice Clark’s group (WA), V. Williams (Parramatta NSW, 1880s) and R. Shinkfield (Adelaide SA, 1920s to 1970s) either. Michael Buhagiar and his group recorded it on several occasions during the period 1971 to 1977. In Buhagiar’s shower list he records a weak shower at an average radiant at R.A. 91° and Decl. –64°. This was identified from six plotted radiants. Buhagiar describes the shower as active from 14 until 21 October with a maximum on 15 October. Further observations were recorded by Darryl Skelsey in 1972 and 1973 at Colo NSW. The radiant on 16 October 1972 was at RA 108° and Decl.  –58° and on 12 October 1973 at RA 97° and Decl. –56°. The shower has been observed on several occasions by WAMS/NAPOMS over the period 1981 – 1997 with a total of 9 plotted radiants providing a mean radiant position of RA 97° and Decl. –52° The shower was listed as the alpha-Carinids #222 in the Southern Hemisphere Meteor Stream List (Wood, 1990). This gives an activity period from 7 to 18 October with a maximum ZHR of 3–4 meteors per hour on 13 October.

6 Conclusion

The Global Meteor Network observations confirm the existence of the minor meteor shower known as the A Carinids (CRN#842), which displayed an outburst in 2025. The orbit parameters obtained by GMN are in good agreement with those derived by Jenniskens (2023) based on CAMS low-light video cameras, except for the eccentricity and the Sun-centered ecliptic longitude. The shower has been noticed by visual meteor observers as a weak activity source in the 20th century.

Acknowledgments

This report is based on the data of the Global Meteor Network (Vida et al., 2020a; 2020b; 2021) which is released under the CC BY 4.0 license. We thank all 825 participants in the Global Meteor Network project for their contribution and perseverance. A list with the names of the volunteers who contribute to GMN has been published in the 2024 annual report (Roggemans et al., 2025). The following 229 cameras recorded A Carinids that made this study possible: AU0001, AU0002, AU0003, AU000A, AU000B, AU000C, AU000D, AU000E, AU000F, AU000G, AU000L, AU000Q, AU000R, AU000S, AU000T, AU000U, AU000V, AU000W, AU000X, AU000Y, AU000Z, AU0010, AU001A, AU001B, AU001D, AU001E, AU001F, AU001K, AU001P, AU001Q, AU001R, AU001S, AU001U, AU001V, AU001W, AU001X, AU001Y, AU001Z, AU0021, AU0028, AU0029, AU002B, AU002C, AU002D, AU0030, AU003E, AU003G, AU003J, AU0042, AU0043, AU0046, AU0047, AU0048, AU004J, AU004K, AU004L, AU004Q, BR000M, BR000Q, BR000T, BR000Y, BR001M, BR001T, BR001U, BR002A, BR002C, CL0002, CL0003, NZ0001, NZ0002, NZ0003, NZ0004, NZ0007, NZ0008, NZ000A, NZ000B, NZ000C, NZ000D, NZ000F, NZ000G, NZ000H, NZ000K, NZ000L, NZ000M, NZ000N, NZ000P, NZ000Q, NZ000R, NZ000S, NZ000T, NZ000U, NZ000V, NZ000W, NZ000X, NZ000Y, NZ000Z, NZ0010, NZ0011, NZ0012, NZ0013, NZ0014, NZ0015, NZ0016, NZ0017, NZ0018, NZ0019, NZ001A, NZ001C, NZ001E, NZ001G, NZ001H, NZ001L, NZ001N, NZ001P, NZ001Q, NZ001R, NZ001S, NZ001V, NZ001Y, NZ001Z, NZ0020, NZ0021, NZ0022, NZ0023, NZ0024, NZ0025, NZ0026, NZ0027, NZ0029, NZ002B, NZ002C, NZ002D, NZ002E, NZ002F, NZ002G, NZ002H, NZ002J, NZ002K, NZ002L, NZ002N, NZ002P, NZ002Q, NZ002R, NZ002S, NZ002T, NZ002U, NZ002V, NZ002W, NZ002X, NZ002Y, NZ002Z, NZ0030, NZ0032, NZ0033, NZ0034, NZ0035, NZ0036, NZ0037, NZ0038, NZ0039, NZ003A, NZ003B, NZ003C, NZ003E, NZ003G, NZ003H, NZ003K, NZ003N, NZ003Q, NZ003R, NZ003S, NZ003T, NZ003V, NZ003W, NZ003Y, NZ003Z, NZ0040, NZ0041, NZ0042, NZ0044, NZ0045, NZ0046, NZ0049, NZ004A, NZ004B, NZ004C, NZ004D, NZ004E, NZ004H, NZ004J, NZ004L, NZ004M, NZ004N, NZ004R, NZ004S, NZ004T, NZ004U, NZ004V, NZ004W, NZ004X, NZ004Y, NZ004Z, NZ0051, NZ0059, NZ005A, NZ005B, NZ005C, NZ005D, NZ005E, NZ005F, NZ005G, NZ005J, NZ005K, NZ005L, NZ005M, NZ005N, NZ005Z, NZ0061, NZ0063, NZ0065, NZ0066, NZ0067, NZ0068, NZ0069, ZA0002, ZA0006, ZA0007, ZA0008, ZA000C.

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