By Damir Šegon, Denis Vida and Paul Roggemans
Abstract: A new meteor shower on a retrograde Halley-type comet orbit (TJ = –0.69) has been detected by the Global Meteor Network during an outburst that lasted about 3.5 hours on August 26–27, 2025 (153.61° < λʘ < 153.75°). Meteors belonging to the new shower were observed between 145° < λʘ < 155° from a radiant at R.A. = 47.6° and Decl.= +11.4° in the constellation of Aries, with a geocentric velocity of 68.5 km/s. The new meteor shower has been listed in the Working List of Meteor Showers under the temporary name-designation: M2025-Q1.
Introduction
The GMN radiant map for August 26–27, 2025 shows a clear concentration of related radiants in the constellation of Aries. 33 meteors of this meteor shower were observed by the Global Meteor Network low-light video cameras on 2025 August 26 – 27 in about 30 hours with an outburst of a so far dormant unknown meteor shower that lasted 3.5 hours (Figure 1). The shower was independently observed by cameras in 19 countries (Belgium, Bulgaria, Czechia, Germany, France, Greece, Croatia, Hungary, Italy, South Korea, Luxembourg, the Netherlands, New Zealand, Romania, Russia, Slovenia, Slovakia, United Kingdom and the United States).
The shower had a median geocentric radiant with coordinates R.A. = 47.5°, Decl. = +11.5°, within a circle with a standard deviation of ±0.4° (equinox J2000.0) see Figure 2. The radiant drift in R.A. is +0.34 deg on the sky per degree of solar longitude and +0.06 in Dec., both referenced to λʘ = 153.5° (Figures 3 and 4). The median Sun-centered ecliptic coordinates were λ – λʘ = 254.8°, β = –6.0° (Figure 5). The geocentric velocity was 68.3 ± 0.2 km/s.
This possible new meteor shower was reported to the IAU MDC and added under the temporary identification 2025-Q1.
Figure 1 – Heat map with 3296 radiants obtained by the Global Meteor network on August 26–27, 2025. A distinct concentration is visible in Sun-centered geocentric ecliptic coordinates which was identified as a new meteor shower with the temporary identification M2025-Q1.
Figure 2 – Dispersion on the radiant position.
Figure 3 – The radiant drift.
Figure 4 – The radiant distribution during the solar-longitude interval 152.3° – 153.8° in equatorial coordinates.
Figure 5 – The radiant distribution during the solar-longitude interval 152.3° – 153.8° in Sun centered geocentric ecliptic coordinates.
First detection
The GMN shower association criterion assumes that meteors within 1° in solar longitude, within 3° in radiant, 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). This is a rather strict criterion since meteor showers often have a larger dispersion in radiant position, velocity and activity period. Using these meteor shower selection criteria, 33 orbits have been associated with the new shower in the GMN meteor orbit database and the mean orbit has been listed in Table 1.
Another search method
Another method has been applied to check this new meteor shower discovery. The starting point here can be any visually spotted concentration of radiant points or any other indication for the occurrence of similar orbits. The method has been described before (Roggemans et al., 2019). The main difference with the method applied in Section 2 is that three different discrimination criteria are combined in order to have only those orbits which fit different thresholds of these criteria. The D-criteria that we use are these of Southworth and Hawkins (1963), Drummond (1981) and Jopek (1993) combined. Instead of using a cutoff value for the threshold of the D-criteria these values are considered in different classes with different thresholds of similarity. Depending on 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 outburst occurred during the solar-longitude interval 152.3° – 153.8° and only this time interval has been considered for the first detection. To check for the presence of meteor shower members outside this interval a sample of the orbit database from λʘ = 140° until λʘ = 155.3°, the latest data available at the time of this analysis, has been used for the shower search.
To generate an initial reference orbit to approach the most likely representative orbit for this new meteor shower, all orbits with 253° < λg – λʘ < 263°, –9° < β < –3° and 64 km/s < vg < 72 km/s were selected. This sample counted 165 orbits which included the concentration caused by the new shower outburst. The mean orbit for this selection was used as a reference orbit to start an iterative procedure to approach the most likely mean orbit for the new meteor shower in this sample. The iteration was started with DSH < 0.20, DD < 0.08 and DJ < 0.20 as thresholds to filter out sporadic contamination. The procedure converged at a mean orbit valid for DSH < 0.05, DD < 0.02 and DJ < 0.05 as threshold values.
This method resulted in a mean orbit with 41 related orbits that fit within the similarity threshold with DSH < 0.125, DD < 0.05 and DJ < 0.125, recorded 2025 August 18–28. 21 of these orbits were recorded during the short time interval 152.3° < λʘ < 153.8°. The plot of the radiant positions in equatorial coordinates, color coded for different D-criteria thresholds, shows a large dispersion for the threshold values larger than DD < 0.05 (Figure 6) with a dense concentration of radiants that fit DSH < 0.125, DD < 0.05 and DJ < 0.125 or better.
Figure 6 – The radiant distribution during the solar-longitude interval 140° – 155° in equatorial coordinates, color coded for different values of the DD orbit similarity criterion.
Figure 7 – The radiant distribution during the solar-longitude interval 140° – 155° in Sun-centered geocentric ecliptic coordinates, color coded for different values of the DD orbit similarity criterion.
Looking at the Sun-centered geocentric ecliptic coordinates the radiant drift caused by of the Earth moving on its orbit around the Sun is compensated and a more compact radiant becomes visible (Figure 7). The sky is densely covered with sporadic radiants in this region, so there is a lot of risk for contamination with sporadics when identifying meteor showers. There is another strong concentration visible at λg – λʘ = 250° and β = –20° identified as the nu Eridanids (NUE#337) which have their main activity one week later.
Figures 8 and 9 show that the selected meteors, identified as members of the new meteor shower do not affect the evenly distribution of the sporadic radiant background.
The diagram with the inclination against the longitude of perihelion (Figure 10) shows a strong concentration for the selected orbits with a lot dispersion for the orbits that fit the more tolerant threshold values for the D-criteria.
Figure 8 – The M2025-Q1 radiants for DD < 0.05 during the solar-longitude interval 140° – 155° in Sun-centered geocentric ecliptic coordinates, with the sporadic radiants marked in grey.
Figure 9 – The sporadic radiants during the solar-longitude interval 140° – 155° in Sun-centered geocentric ecliptic coordinates, with M2025-Q1 radiants marked in grey for DD < 0.05.
Figure 10 – The diagram of the inclination i against the longitude of perihelion Π color coded for different classes of D criterion threshold.
The concentration of radiants is outstanding when we limit the orbit sample plotted in Figures 7 and 10 to the time interval 153° < λʘ < 154° (Figures 11 and 12), the very high threshold points remain. The orange dots with 0.06 < DD < 0.04 in Figures 7 and 10 are most probably related to this outburst but occurred before and after the outburst and appear more dispersed.
Figure 11 – The radiant distribution during the solar-longitude interval 153° – 154° in Sun-centered geocentric ecliptic coordinates, color coded for different values of the DD orbit similarity criterion.
Figure 12 – The diagram of the inclination i against the longitude of perihelion Π color coded for different classes of D criterion thresholds during the solar-longitude interval 153° – 154°.
Orbit and parent body
The final mean orbits obtained by the two methods are listed in Table 1. There are five orbits from previous years among the 33 orbits used to define 2025-Q1. Five of these 33 orbits fail to fit the D criteria thresholds with DSH < 0.125, DD < 0.05 and DJ < 0.125 for their own mean orbit. The alternative shower identification method using the D-criteria thresholds found 41 orbits, 19 of which occurred before or after the interval 153° < λʘ < 154°. 21 identical meteors were classified as new shower members by both methods. Six meteors used by the first method were not detected by the second method. The second method identified three orbits as shower members that were not detected by the first method apart from the 17 meteors recorded before or after the outburst. Despite the differences in the composition of the orbit selections, the resulting mean orbits are in good agreement, mainly defined by the 21 orbits in common. Figure 13 shows the two orbits plotted in the solar system with 2025-Q1 as reported to the IAU MDC, while DD < 0.05 includes 17 outliers recorded before and after the outburst and three meteors during the outburst that were not included in the M2025-Q1 selection. The apparent large difference in aphelia is due to the slightly higher average velocity and therefore larger value for the eccentricity e.
Table 1 – Comparing the new meteor shower, derived by two different methods, M2025-Q1 the orbital parameters as initially derived, the parameters under DD < 0.05 were derived from the method described in Section 3, (*) is the solution for the outburst interval 153°–154° in solar longitude.
| M2025-Q1 | DD < 0.05 | DD < 0.05(*) | |
| λʘ (°) | 153.5 | 153.7 | 153.7 |
| λʘb (°) | 152.3 | 145.0 | 153.0 |
| λʘe (°) | 153.9 | 155.0 | 154.0 |
| αg (°) | 47.5 | 47.0 | 47.6 |
| δg (°) | +11.5 | +11.4 | +11.5 |
| Δαg (°) | +0.34 | +0.78 | +1.00 |
| Δδg (°) | +0.06 | +0.22 | +0.35 |
| vg (km/s) | 68.3 | 68.7 | 68.7 |
| λg (°) | 48.3 | 47.8 | 48.4 |
| λg – λʘ (°) | 254.8 | 254.8 | 254.6 |
| βg (°) | –6.0 | –6.0 | –6.0 |
| a (A.U.) | 12.7 | 20.0 | 26.6 |
| q (A.U.) | 0.804 | 0.816 | 0.806 |
| e | 0.937 | 0.959 | 0.970 |
| i (°) | 168.7 | 168.8 | 168.7 |
| ω (°) | 54.7 | 52.5 | 53.9 |
| Ω (°) | 333.5 | 331..5 | 333.7 |
| Π (°) | 28.2 | 27.8 | 27.6 |
| Tj | –0.69 | –0.82 | –0.89 |
| N | 33 | 41 | 22 |
Figure 13 – Comparing the mean orbit based on the shower identification according to the two methods, blue is for M2025-Q1 and red for the alternative shower search method with DD < 0.05 in Table 1. (Plotted with the Orbit visualization app provided by Pető Zsolt).
Figure 14 shows the orbits in the inner solar system. The dust of M2025-Q1 crosses the Earth orbit at its ascending node, hitting the Earth almost head-on from below the ecliptic plane.
The Tisserand’s parameter Tj identifies the orbit as of a Halley comet type in this case with a retrograde orbit. A parent-body search top 10 includes candidates with a threshold for the Drummond DD criterion value lower than 0.25 but none of which can be associated with any certainty (Table 2).
Figure 14 – Comparing the mean orbits in the inner solar system, blue is for M2025-Q1 and red for the other shower search method with DD < 0.05 in Table 1. (Plotted with the Orbit visualization app provided by Pető Zsolt).
Table 2 – Top ten matches of a search for possible parent bodies with DD < 0.25.
| Name | DD |
| C/1698 R1 | 0.111 |
| C/2020 R4 (ATLAS) | 0.129 |
| C/1946 K1 (Pajdusakova-Rotbart-Weber) | 0.13 |
| C/1893 N1 (Rordame-Quenisset) | 0.133 |
| C/1862 N1 (Schmidt) | 0.162 |
| C/1864 N1 (Tempel) | 0.178 |
| C/1917 H1 (Schaumasse) | 0.184 |
| C/1999 S4 (LINEAR) | 0.211 |
| C/1947 S1 (Bester) | 0.219 |
| C/2002 T7 (LINEAR) | 0.222 |
Activity in past years
A search in older GMN orbit data resulted in 93 possible orbits with DD < 0.06, most of them at solar longitudes before or after the 2025 outburst. Six in 2020, 15 in 2021, 18 in 2022 with one during the outburst interval, 26 in 2023 with two during the outburst interval and 28 orbits in 2024 with 7 during the outburst interval. No other meteor orbit datasets were checked. The activity in the past years indicates that M2025-Q1 may display weak annual activity between solar longitudes 140° and 165°.
Conclusion
The discovery of a new meteor shower with a radiant in the constellation of Aries based on thirty-two meteors during August 26–27, 2025 has been confirmed by using two independent meteor shower search methods. The resulting mean orbits for both search methods are in good agreement. All meteors appeared during the solar-longitude interval 145° – 155°, with most events in less than 3.5 hours during an outburst on 26–27 August (λʘ = 153.61°–153.75°). Orbits of this meteor shower were detected in previous years. Meanwhile this new meteor shower was independently reported by the meteor camera network in Belarus and Ukraine using UFOOrbit with four paired meteors between solar longitude 153.67° and 153.73° (Harachka and Aitov, 2025).
Acknowledgment
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).
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